Novel lactic acid bacteria, dairy products using the strain thereof, and methods for producing the same.

Abstract

To provide a novel lactic acid bacterium strain that is usable as a starter useful for production of dairy products, especially natural cheese, allows reduction of the production time in cheese production, and enables the produced cheese to retain a large number of live bacteria.SOLUTION: A lactic acid bacterium being Lactococcus cremoris strain 210 (Accession No.: NITE P-04049) or Lactococcus cremoris strain 215 (Accession No.: NITE P-04050).SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to starter lactic acid bacteria for dairy product manufacturing, which are fermentation microorganisms necessary for the production of dairy products such as natural cheese. [Background technology]

[0002] In recent years, the consumption of natural cheese in Japan has been on the rise, and consequently, the production of domestic cheese has also increased. Natural cheeses develop a wide variety of flavors, textures, and consistency depending on the manufacturing process. Major factors influencing the taste include milk quality, milk processing methods, cheese starters (bacteria such as lactic acid bacteria, filamentous fungi, and yeast), enzymes, and ripening conditions. In Europe, these factors have been combined and modified over a long history, resulting in the production of cheeses that suit the tastes of people in each country and region, which has led to the diversity of cheeses we see today. In recent years, along with the spread of natural cheeses as mentioned above, natural cheeses with diverse flavors and textures have also appeared on the market in Japan, but the variety is still smaller compared to Europe. One of the important factors that determine the taste of natural cheese is the cheese starter, such as lactic acid bacteria, used during production. In the cheese manufacturing process, the starter that contributes to lactic acid fermentation (main starter) produces lactic acid in the early stages of production, lowering the pH of the raw milk, suppressing the growth of spoilage bacteria, and promoting the coagulation of milk proteins by rennet. On the other hand, the auxiliary starter, which is used in conjunction with the main starter, does not particularly affect the initial stages of cheese manufacturing, but during the cheese's maturation period, it breaks down proteins and lipids, promoting maturation and creating unique flavors such as taste, aroma, and texture. Both the main starter and the auxiliary starter are commercially available in powder form, freeze-dried from high concentrations of live bacteria, for convenience and hygiene reasons.

[0003] Currently, most cheese starters used in natural cheese production in Japan are imported from overseas. The lactic acid bacteria used in commercially available imported cheese starters are isolated and identified from strains that have been passed down through generations by traditional cheese makers. These cheese starters, either individually or in combination, are widely distributed globally because they provide stable lactic acid production and enable the production of high-quality cheese. However, because there are only a limited number of global starter manufacturers, the options for changing the starter to characterize a cheese are extremely limited. Furthermore, while the lactic acid production capacity and rate of lactic acid bacteria used in commercially available cheese starters are stable, this makes it difficult to shorten the production time in cheese manufacturing. Furthermore, the lactic acid bacteria that make up commercially available cheese starter are 1 x 10⁶ on the first day of production. 9 The bacterial concentration increases to about cfu / g, but it decreases rapidly from about one month into maturation. Although cheese is a food from which lactic acid bacteria can be ingested, there was a problem that the number of viable lactic acid bacteria contained in cheese decreased rapidly as the maturation period lengthened. Although there have been reports on lactic acid bacteria useful for natural cheese production (e.g., Patent Documents 1-3), no reports have yet been published that can solve the above-mentioned problems. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Special Publication No. 2004-507265 [Patent Document 2] Japanese Patent Publication No. 2017-221231 [Patent Document 3] Japanese Patent Publication No. 2019-047831 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention aims to provide a novel lactic acid bacteria strain that can be used as a starter for dairy products, particularly natural cheese production, thereby shortening cheese production time and exhibiting high survival rate in the produced cheese. [Means for solving the problem]

[0006] The inventors diligently conducted research to solve the above problems and selected lactic acid bacteria with high milk fermentation ability from the lactic acid bacteria library held by the National Agriculture and Food Research Organization. As a result of investigating the characteristics of these selected lactic acid bacteria in relation to cheese production, it was found that the cheese production time could be shortened and the number of viable bacteria in the produced cheese was increased, thus completing the present invention.

[0007] The present invention is summarized in the following terms: 1. Lactic acid bacteria that are Lactococcus cremoris strain 210 (accession number: NITE P-04049) or Lactococcus cremoris strain 215 (accession number: NITE P-04050). 2. The lactic acid bacteria described in 1., characterized in that it is used for the manufacture of dairy products. 3. The lactic acid bacteria described in 1., characterized by being used as a cheese starter culture. 4.1. to 3. Dairy products containing lactic acid bacteria as described in any one of these items. Cheese containing the lactic acid bacteria described in any one of items 5.1 to 5.3. A method for producing dairy products, characterized by using lactic acid bacteria described in any one of sections 6.1 to 6.3. A method for producing cheese, characterized by using lactic acid bacteria described in any one of sections 7.1 to 7.3. [Effects of the Invention]

[0008] The novel lactic acid bacteria in this invention have excellent lactic acid production capabilities, and when used as a starter in dairy product manufacturing, particularly cheese manufacturing, it is possible to shorten the time required for the curd molding process. Furthermore, the cheese obtained through this cheese manufacturing process has the advantage of having a high number of viable bacteria, making it possible to develop new foods for consuming lactic acid bacteria.

Brief Description of the Drawings

[0009] [Figure 1] It is a graph showing the pH change every hour from the start of fermentation at a growth temperature of 30°C for 7 species of lactic acid bacteria in Confirmation Test 1 of the properties of the novel lactic acid bacterial strain of Example 4. [Figure 2] It is a graph showing the pH change every hour from the start of fermentation at a growth temperature of 40°C for 7 species of lactic acid bacteria in Confirmation Test 1 of the properties of the novel lactic acid bacterial strain of Example 4. [Figure 3] It is a graph showing the salt sensitivity of 7 species of lactic acid bacteria in Confirmation Test 2 of the properties of the novel lactic acid bacterial strain of Example 5. [Figure 4] It is a graph showing the low-temperature growth ability of 7 species of lactic acid bacteria in Confirmation Test 2 of the properties of the novel lactic acid bacterial strain of Example 5. [Figure 5] It is a graph showing the high-temperature growth ability of 7 species of lactic acid bacteria in Confirmation Test 2 of the properties of the novel lactic acid bacterial strain of Example 5. [Figure 6] It is a graph showing the time (minutes) for 3 species of lactic acid bacteria to reach pH 5.0 in Confirmation Test 1 of the lactic acid production ability of the novel lactic acid bacterial strain of Example 6. [Figure 7] It is a graph showing the time (minutes) for 6 test groups to reach pH 5.6 in Confirmation Test 2 of the lactic acid production ability of the novel lactic acid bacterial strain of Example 7. [Figure 8] It is a graph showing the viable count in cheese produced by the novel lactic acid bacterial strain of Example 8 for Gouda cheese produced using 3 test groups as starters, for each aging period (0, 1, 30, 60, 90, 180, 360 days). [Figure 9] It is a graph showing the time (minutes) for 4 test groups to reach pH 5.6 in Confirmation Test 3 of the lactic acid production ability of the novel lactic acid bacterial strain of Example 10. [Figure 10] It is a graph showing the change in moisture content in cheese on the 1st, 30th, 60th, 90th, and 180th days after aging of the obtained Gouda cheese in Confirmation Test 3 of the lactic acid production ability of the novel lactic acid bacterial strain of Example 10. [Figure 11]This graph shows the changes in the fat content of the Gouda cheese obtained in the lactic acid production ability confirmation test 3 of the novel lactic acid bacteria strain of Example 10, on day 1, day 30, day 60, day 90, and day 180 after maturation. [Figure 12] This graph shows the changes in pH values ​​in the Gouda cheese obtained in the lactic acid production ability confirmation test 3 of the novel lactic acid bacteria strain of Example 10, on days 1, 30, 60, 90, and 180 after maturation. [Figure 13] This graph shows the changes in the number of viable bacteria in the Gouda cheese obtained in the lactic acid production ability confirmation test 3 of the novel lactic acid bacteria strain of Example 10, on day 1, day 30, day 60, day 90, and day 180 after maturation. [Figure 14] This graph shows the changes in the amount of free amino acids (μmol / g) in the Gouda cheese obtained in the confirmation test 3 of the lactic acid production ability of the novel lactic acid bacteria strain of Example 10, after 90 days of aging. [Figure 15] This graph shows the change in the amount of free glutamic acid (μmol / g) in the Gouda cheese obtained in the confirmation test 3 of the lactic acid production ability of the novel lactic acid bacteria strain of Example 10, after 90 days of aging. [Figure 16] This graph shows the glutamic acid concentration (μmol / g) in the Gouda cheese obtained in the lactic acid production ability confirmation test 3 of the novel lactic acid bacteria strain of Example 10, at 1 day, 30 days, 60 days, 90 days, and 180 days after maturation.

[0010] This invention relates to 210 strains of Lactococcus cremoris (accession number: NITE P-04049) and 215 strains of Lactococcus cremoris (accession number: NITE P-04050) selected from the lactic acid bacteria library held by the National Agriculture and Food Research Organization (NARO). The present invention will be described in detail below.

[0011] <Novel Lactobacillus Strain> The novel lactic acid bacteria of the present invention, Lactococcus cremoris strain 210 (accession number: NITE P-04049) and Lactococcus cremoris strain 215 (accession number: NITE P-04050), are lactic acid bacteria selected from the lactic acid bacteria library held by the National Agriculture and Food Research Organization (NARO). Lactococcus cremoris strain 210 was isolated from pickled daikon radish, and Lactococcus cremoris strain 215 was isolated from pickled mizuna greens. These lactic acid bacteria strains have been deposited with the Patent Microorganism Depositary Center of the National Institute of Technology and Evaluation (NITE), with accession numbers NITE P-04049 and NITE P-04050, respectively (deposit date: December 20, 2023). As will be described later, the two novel lactic acid bacteria strains of the present invention have excellent characteristics, including high lactic acid production capacity during cheese production and the ability to survive in cheese for an extremely long period during the maturation process.

[0012] <Cheese production> Cheese production is divided into two stages: curd forming and aging. The curd forming process involves separating the components of raw milk into solids and water (whey) using acidification, enzymatic reactions, and heating, and then removing the whey to solidify the milk. Lactic acid bacteria used in the starter are essential biological ingredients in cheese production, as they are involved in the acidification of the raw milk and part of the enzymatic reactions. Their basic role is to lower the pH of the raw milk by breaking down lactose and producing lactic acid, thereby preventing the growth of harmful microorganisms, and to assist the action of rennet, a coagulating enzyme, in promoting coagulation and separation from the curd. The time required for curd formation, the first step in cheese production, is greatly influenced by the lactic acid production capacity of the starter. Therefore, using a starter with poor lactic acid production capacity will result in slower syneresis and a longer curd formation time. The maturation process involves storing the molded curd at a constant temperature and humidity. During this process, enzymes originally present in the raw milk, as well as rennet and intracellular and extracellular enzymes released into the curd through the autodigestion of starter lactic acid bacteria, promote the breakdown of casein and milk fat, and the production of aromatic compounds, creating the unique texture and flavor of the cheese. In particular, the molding process involves 1 x 10 9 Lactic acid bacteria that proliferate to levels exceeding cfu / g are a major source of enzymes, and a sufficient concentration of these bacteria is required. The changes in the viable cell counts of the main starter bacteria, co-starter bacteria, and non-starter bacteria that are accidentally introduced from the environment, which form the viable microbiota of aged cheese, depend on the characteristics of the constituent strains. For example, the typical cell count changes of Lactococcus lactis and Lactococcus cremoris, which constitute the main starter, are highest during the curd forming process, gradually decrease from about one month of aging, and become about 1 / 1,000 of that after three months. As the main starter bacteria decrease, the source of enzymes that work in aging shifts to co-starter bacteria and non-starter bacteria. In particular, in cheese production that does not use co-starters or mold starters, the contribution of the main starter bacteria is significant even in the aging process, and the changes in their cell count and enzyme activity directly affect the final quality of the cheese. Natural cheese is recognized as a food that allows you to ingest live lactic acid bacteria, but hard and semi-hard cheeses require a maturation period of at least 3-4 months to develop the unique qualities of each cheese type and reach their optimal eating stage. Therefore, the number of bacteria derived from the main starter in cheese at its optimal consumption stage is 1 x 10⁻⁶. 6 Many of them are at or below the CFU / g level.

[0013] The two novel lactic acid bacteria strains of the present invention were selected for their properties that make them suitable for use as a main starter culture. When these two novel lactic acid bacteria strains are used as a main starter culture, they exhibit excellent lactic acid production capabilities during the curd molding process in cheese production, resulting in a remarkably superior effect of shortening the time required for cheese production. Furthermore, the two novel lactic acid bacteria strains of the present invention possess lactic acid production capacity comparable to that of the standard Lactococcus cremoris strain at optimal growth temperatures, and can grow at temperatures higher and lower than the upper limit of growth temperature for the standard Lactococcus cremoris strain, while maintaining high lactic acid production capacity. Furthermore, it can grow even at a 5% sodium chloride salt concentration, which is insufficient for the proliferation of typical Lactococcus cremoris. The two novel lactic acid bacteria strains of the present invention can grow at 10°C, a temperature often used for cheese maturation, and at a salt concentration of 2% sodium chloride, which is approximately the same as the salt concentration of cheese. The number of viable bacteria in cheese produced using these two lactic acid bacteria strains as the main starter is 1 × 10⁶, which is about the same as when using existing or commercially available starters in the cheese molding process. 9 It increases to cfu / g and remains at 1 x 10 over a long period during the maturation process, which is carried out at 10°C. 9 It exhibits the excellent effect of maintaining an extremely high bacterial count exceeding cfu / g. In cheese production, either of the two novel lactic acid bacteria strains of the present invention may be used, or both strains may be used in combination.

[0014] <Cheese manufacturing method> This invention relates to a method for producing dairy products using two novel strains of lactic acid bacteria, and more particularly to a method for producing cheese. For example, we will briefly describe a method for producing cheese using one or both of the two new lactic acid bacteria strains. The origin of the milk used as a raw material is not limited; cow's milk, goat's milk, sheep's milk, buffalo milk, donkey's milk, etc., can be used, but cow's milk or goat's milk is preferred among these. Cheese production involves adding one or two of two novel lactic acid bacteria strains as the main starter to raw milk for cheese production to induce lactic acid production, creating acidity and flavor compounds. Rennet is then added to curdle the milk. Next, whey is removed from the curd through cutting and cooking operations. The curd is then placed in a mold and pressed to remove the whey and shape it. After shaping, salt is added to impart saltiness and shelf life, and water activity is adjusted as needed. Except for fresh cheese, aging is performed, and the cheese can be produced in the same manner as known cheese production methods.

[0015] <Cheese> The cheese produced using the two novel lactic acid bacteria strains of the present invention is not particularly limited. Cheese is broadly classified into natural cheese and processed cheese, but the two novel lactic acid bacteria strains of the present invention are suitable for the production of natural cheese and have excellent lactic acid production ability in milk fermentation, making them suitable for the production of fresh cheeses such as cottage cheese and mozzarella cheese. Furthermore, because they have the characteristic of reaching and maintaining a high number of viable bacteria in cheese curd, they are also suitable for the production of aged cheeses such as Gouda cheese, Cheddar cheese, and Camembert cheese.

[0016] <Fermented dairy products> Fermented dairy products produced using the two novel lactic acid bacteria strains of the present invention are not particularly limited. Examples of fermented milk products include fermented milk, dairy lactic acid bacteria beverages, and lactic acid bacteria beverages. The two novel lactic acid bacteria strains of the present invention are suitable for the production of these products because they have excellent lactic acid production capabilities in milk fermentation. Furthermore, it is possible to impart a different flavor from that of Streptococcus thermophilus and Lactobacillus delbruickii subspecies bulgaricus, which have been widely used in the production of these products in the past. For example, in milk fermentation using the two novel lactic acid bacteria strains of the present invention, the lactic acid bacteria rapidly produce lactic acid from the start of fermentation, lowering the pH to around 5. However, once the pH reaches 4.4-4.5, it does not drop any further, and the fermented milk does not become excessively sour (see Figure 1). The following briefly describes a method for producing fermented dairy products using one or both of the two new lactic acid bacteria strains. The origin of the milk used as a raw material is not limited; cow's milk, goat's milk, sheep's milk, buffalo milk, donkey's milk, etc., can be used, but cow's milk or goat's milk is preferred among these. The manufacturing method involves adding one or both of the two novel lactic acid bacteria strains to pasteurized raw milk and fermenting it for 8 to 12 hours at the optimal temperature for lactic acid bacteria growth. Sweeteners, fruit juice, gelatin, etc., may be added to enhance palatability. Furthermore, by using a blender or similar device to homogenize the mixture, it is possible to produce drinkable or frozen fermented milk.

[0017] As described above, the two novel lactic acid bacteria strains of the present invention, Lactococcus cremoris strain 210 (isolated from pickled daikon radish) and Lactococcus cremoris strain 215 (isolated from pickled mizuna greens), exhibit high salt tolerance and can grow under a salt concentration of 5% sodium chloride. They can also grow at low temperatures of 10°C. Based on these findings, the two novel lactic acid bacteria strains of the present invention are also useful as starters for plant-based fermented foods such as pickles.

[0018] In this invention, dairy products refer to products that use milk as a raw material. Specifically, examples include yogurt, cheese, cream, butter, butter oil, concentrated whey, ice cream, concentrated milk, skimmed concentrated milk, unsweetened condensed milk, unsweetened skimmed condensed milk, sweetened condensed milk, sweetened skimmed condensed milk, whole milk powder, skimmed milk powder, cream powder, whey powder, protein-concentrated whey powder, buttermilk powder, sweetened milk powder, modified milk powder, fermented milk, lactic acid bacteria beverages, and milk beverages. Among these, cheese is preferred as the dairy product of this invention. Examples of raw materials for dairy products include cow's milk, as well as goat's milk, sheep's milk, buffalo milk, and donkey's milk. [Examples]

[0019] The present invention will be described below with reference to examples, but the technical scope of the present invention is not limited thereto.

[0020] <Example 1: Identification of Novel Lactic Acid Bacteria Strains> Lactococcus cremoris and Lactococcus lactis, both belonging to the genus Lactococcus, are representative strains used in milk processing starters. However, their roles in production are different, and when considering industrial applications, strain identification is crucial. Both of these two strains produce lactic acid and contribute to the pH decrease of raw milk. Lactococcus cremoris often dies in the initial stage of ripening and serves as a source of enzymes involved in ripening in many cases. In contrast, Lactococcus lactis often has resistance to factors such as pH, temperature, and salt concentration, and remains active for a long time in products such as cheese that require a long ripening period, and then dies to become a source of enzymes, which is different. Based on the above circumstances, two novel lactic acid bacteria strains of the present invention were identified. The names of the microbial strains with publicly available genomic information used for strain identification are shown below. 210 strain: Lactococcus cremoris 210 strain 215 strain: Lactococcus cremoris 215 strain ATCC 19435T: Lactococcus lactis subsp. lactis type strain ATCC19435 T CCUG 32210T: Lactococcus lactis subsp. hordniae type strain CCUG32210 T ATCC 19257T: Lactococcus cremoris subsp. cremoris type strain ATCC19257 T DSMZ 21502T: Lactococcus cremoris subsp. trachtae type strain DSMZ21502 T ATCC means the American Type Culture Collection, CCUG means the Culture Collection, University of Göteborg, Sweden, and DSMZ means the German Collection of Microorganisms and Cell Cultures. The results are shown below.

[0021] [Table 1]

[0022] Strains 210 and 215 cannot be clearly distinguished by 16S rRNA gene sequencing, a commonly used method for identifying bacterial species. Furthermore, phenotypic classification identifies them as Lactococcus lactis. However, as shown in Table 1, ANI (Average Nucleotide Identity) and dDDH (digital DNA-DNA Hybridization) methods, which compare homology across the entire genome, identified them as Lactococcus cremoris. For the ANI, whole-genome comparisons were performed using assembled sequences. Similarity was calculated for aligned regions, and strains with a homology of 95% or higher (corresponding to a DDH homology of 70%) were considered the same species. ANI is a species identification index that uses the average similarity between DNA regions that show homology between two genomes. Here, we used orthoani (https: / / github.com / althonos / orthoani) to calculate the ANI between each genome sequence. dDDH is a genome sequence-based calculation method that shows a high correlation with DDH, a test method that indirectly calculates homology between base sequences. Here, we calculated the estimated DDH value using GGDC (https: / / ggdc.dsmz.de / ggdc.php#).

[0023] <Example 2: Antimicrobial susceptibility of novel lactic acid bacteria strains> To confirm whether the two novel lactic acid bacteria strains of the present invention are suitable for food manufacturing applications, tests were conducted to determine their susceptibility to antimicrobial substances. (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains 215 strains: Lactococcus cremoris 215 strains CH1 strain: Lactococcus lactis CH1 strain (a milk fermentation starter culture manufactured by Christian Hansen) 527 strain: Lactococcus lactis 527 strain (a milk fermentation starter culture distributed by the Japan Dairy Technology Association) (2) Test method Antimicrobial susceptibility testing was performed using the disk diffusion method. Each test bacterium was pre-cultured overnight in 5 mL of MRS medium (OXOID), washed once with 0.85% sodium chloride aqueous solution, and then suspended in an equal volume of 0.85% sodium chloride aqueous solution. 100 μL of the suspension was mixed onto an MRS agar plate, and Sensi-disks containing the antimicrobial substances listed in Table 2 (manufactured by Becton Dickinson Japan Co., Ltd.) were placed on the plate using a dispenser (manufactured by Becton Dickinson Japan Co., Ltd.). The plates were incubated at 30°C for 24 hours. After incubation, susceptibility was determined by the presence or absence of an inhibition zone formed around each disk.

[0024] (3) Results The susceptibility of the four lactic acid bacteria strains tested to antimicrobial substances is summarized in Table 2 below. In Table 2, "+" indicates susceptibility, and "-" indicates insensitivity. [Table 2]

[0025] As shown in Table 2, strains 210 and 215 exhibited antimicrobial susceptibility equivalent to that of commercially available strains, confirming their applicability to food manufacturing applications. <Example 3: Sugar utilization of a novel lactic acid bacteria strain> To clarify the assimilation characteristics of two novel lactic acid bacteria strains of the present invention, their sugar assimilation capabilities were tested. (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains 215 strains: Lactococcus cremoris 215 strains CH1 strain: Lactococcus lactis CH1 strain (a milk fermentation starter culture manufactured by Christian Hansen) 527 strain: Lactococcus lactis 527 strain (a milk fermentation starter culture distributed by the Japan Dairy Technology Association) (2) Test method The sugar assimilation test was performed using API50CHL Medium and API50CH (BioMerieux, Sa, Metropole de Lyon, France). Each test bacterium was cultured anaerobically overnight in 5 mL of MRS medium (OXOID), washed twice with 0.85% sodium chloride aqueous solution, and then suspended in 2 mL of suspension medium. After adding the suspension to an amount that resulted in a McFarland turbidity of 2 to API50CHL Medium and stirring, the suspension was dispensed into each tube portion of the API50CH plate, and then mineral oil was overlaid on the cup portion. After incubation at 30°C under aerobic conditions for 48 hours, the plate was evaluated, and the resulting biochemical profile was recorded on APIWEB. TM The data was entered and the test bacteria were identified.

[0026] (3) Results The sugar utilization capabilities of the four lactic acid bacteria strains tested are summarized in Table 3 below. The meanings of the symbols in Table 3 are summarized in Table 4. [Table 3] [Table 4]

[0027] As shown in Table 3, in the sugar assimilation test, strains 210 and 215 both showed similar assimilation capabilities to the commercially available strains CH1 and 527 of Lactococcus lactis, respectively, and APIWEB TM The strains were identified as Lactococcus lactis with a probability of 99.6%. This indicates that strains 210 and 215 differ from common Lactococcus cremoris and possess similar sugar assimilation capabilities to Lactococcus lactis. Furthermore, in this study, strains 210 and 215 differed from the commercially available strains CH1 and 527 in that they possessed the characteristic of being able to assimilate D-Mannitol.

[0028] <Example 4: Confirmation test of the properties of a new lactic acid bacteria strain 1> To demonstrate the properties of the two novel lactic acid bacteria strains of the present invention, skim milk was fermented at 30°C, the optimal growth temperature for Lactococcus cremoris, and at 40°C, the upper limit of Lactococcus cremoris growth, and their lactic acid production capacity was confirmed. (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains 215 strains: Lactococcus cremoris 215 strains H61 strain: Lactococcus cremoris H61 strain (a milk fermentation starter culture distributed by the Japan Dairy Technology Association) 527 strain: Lactococcus lactis 527 strain (a milk fermentation starter culture distributed by the Japan Dairy Technology Association) Strain 19257: Lactococcus cremoris standard strain ATCC19257 T Strain 19435: Lactococcus lactis reference strain ATCC19435 T CH1 strain: Lactococcus lactis CH1 strain (a milk fermentation starter culture manufactured by Christian Hansen) The name ATCC (American Type Culture Collection) in the strain name refers to the American biological resource bank. (2) Test method Each test bacterium was cultured overnight in GM17 medium (M17 medium (Difco) with 1% glucose added), washed once with 0.85% sodium chloride aqueous solution, and then suspended in an equal volume of 0.85% sodium chloride aqueous solution to prepare the test bacterial suspension. The 10% skim milk used as the test medium was sterilized by heating at 110°C for 5 minutes the day before the test. Immediately before the test, the sterilized skim milk was stored at the test temperature for at least one hour to stabilize the temperature, and each test bacterium was cultured to 1 × 10⁶ units. 7 The culture medium was inoculated to a concentration of cfu / mL and immediately placed at the test temperature. The pH of the skim milk culture medium was measured every hour for up to 24 hours using a pH monitor (Yamagata Toa DDK, YUSB-01) and recorded. Figure 1 shows the pH change at 30°C, and Figure 2 shows the pH change at 40°C.

[0029] As shown in Figure 1, at the optimal growth temperature of 30°C for Lactococcus cremoris and Lactis, the pH of Lactococcus cremoris strains 19257 and H61, and the CH1 cheese starter strain from Christian Hansen, decreased rapidly in the early stages of culture. The pH decrease of strains 210 and 215 was similar to that of strain 527, and faster than that of Lactococcus lactis type strain 19435. Furthermore, the final pH reached was similar to that of strain 19257 and the milk fermentation starter strains 527, H61, and CH1. As shown in Figure 2, at 40°C, which exceeds the upper limit of Lactococcus cremoris growth, the pH decrease in strains 210 and 215 was faster than in the comparison strains Lactis 527 and 19435, and the reached pH was also lower. While the pH decrease in strain CH1 was rapid in the early stages of culture, the reached pH did not reach pH 5. Furthermore, strains 19257 and H61 of Lactococcus cremoris failed to grow, and no pH decrease due to lactic acid production was observed. As shown in Figure 1, it was confirmed that the novel lactic acid bacteria strains 210 and 215 of the present invention have lactic acid production capabilities equivalent to the standard Lactococcus cremoris strain and strains 527, H61, and CH1, which have a proven track record as milk fermentation starters, at the optimal growth temperature of Lactococcus cremoris, which is 30°C. Furthermore, as shown in Figure 2, it was confirmed that the novel lactic acid bacteria strains 210 and 215 of the present invention possess superior lactic acid production capabilities compared to all the comparative strains used in the test at 40°C, the upper limit of growth for Lactococcus cremoris.

[0030] <Example 5: Confirmation test of the properties of a new lactic acid bacteria strain 2> To demonstrate the properties of the two novel lactic acid bacteria strains of the present invention, we confirmed their salt sensitivity and low / high temperature growth capabilities. (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains 215 strains: Lactococcus cremoris 215 strains H61 strain: Lactococcus cremoris H61 strain (a milk fermentation starter culture distributed by the Japan Dairy Technology Association) 527 strain: Lactococcus lactis 527 strain (a milk fermentation starter culture distributed by the Japan Dairy Technology Association) CH1 strain: Lactococcus lactis CH1 strain (a milk fermentation starter culture manufactured by Christian Hansen) (2) Test method Each test bacterium was inoculated into GM17 medium (M17 medium (Difco) with 1% glucose added) the day before the test, and cultured overnight to prepare the test bacterial suspension. In the 10°C and 40°C culture tests, the culture medium was stored at the test temperature for at least one hour before the start of the test to ensure a constant temperature. Each test bacterium was divided into 1 × 10⁶ samples. 7 The cells were inoculated to a concentration of cfu / mL, immediately placed at the test temperature, and the absorbance (OD=620nm) was measured at 8 hours, 24 hours, and 48 hours. In the salt concentration sensitivity test, GM17 medium with 5% sodium chloride was used, and the absorbance (OD=620nm) was measured after incubation at 30°C for a specified time. Salt sensitivity is shown in Figure 3, low-temperature growth characteristics in Figure 4, and high-temperature growth characteristics in Figure 5.

[0031] As shown in Figure 3, the salt concentration tolerance of the novel lactic acid bacteria strains 210 and 215 of the present invention is the same as that of the standard strain 19435 of Lactococcus lactis. T The strain was comparable to that of the 527 milk fermentation starter strains, and higher than the Christian Hansen starter strain CH1. In addition, under the test conditions of GM17 medium with 5% sodium chloride added, the H61 and 19257 strains of Cremoris were also observed. T The plants were unable to grow. As shown in Figure 4, it was confirmed that the low-temperature growth ability of the novel lactic acid bacteria strains 210 and 215 of the present invention was higher than that of all the comparative strains used in the test. As shown in Figure 5, the high-temperature growth ability of the novel lactic acid bacteria strains 210 and 215 of the present invention was confirmed to be as high as that of the lactis species milk fermentation starter strain 527 for the first 8 hours of culture, and the absorbance achieved after 24 and 48 hours of culture was higher than that of all the comparative strains used in the test.

[0032] <Example 6: Confirmation test 1 of the lactic acid production capacity of a novel lactic acid bacteria strain> To demonstrate the properties of the two novel lactic acid bacteria strains of the present invention, their lactic acid production capacity was compared with that of commercially available milk fermentation starter cultures by measuring the time it took to reach a specific pH value. (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains 215 strains: Lactococcus cremoris 215 strains CH1 strain: Lactococcus lactis CH1 strain (a milk fermentation starter culture manufactured by Christian Hansen) (2) Test method To confirm the lactic acid production capacity of two novel lactic acid bacteria strains of the present invention in the fresh cheese manufacturing process, the time it took to reach a specific pH was determined in the string cheese manufacturing process. In fresh cheeses such as mozzarella and string cheese, after curd formation, lactic acid fermentation lowers the pH and heating promotes the removal of whey from the curd, and finally the curd is spread and shaped in hot water. The target pH for spreading and shaping the curd is between 5.0 and 5.4. Therefore, the target pH for this experiment was set at 5.0. Figure 6 shows the time (in minutes) it takes to reach pH 5.0. The different letters on the bar graph in Figure 6 indicate significant differences at the 5% level in multiple comparison tests using the Tukey-Kramer method.

[0033] As shown in Figure 6, the novel lactic acid bacteria strains 210 and 215 of the present invention were found to exhibit a significantly faster decrease in pH during production compared to the CH1 strain, which has a proven track record as a milk fermentation starter, indicating that they have a higher lactic acid production capacity.

[0034] <Example 7: Confirmation test of lactic acid production ability of a novel lactic acid bacteria strain 2> To confirm the lactic acid production capacity of two novel lactic acid bacteria strains of the present invention in the hard and semi-hard cheese manufacturing process, the time it took to reach a specific pH was determined in the Gouda cheese manufacturing process. In the curd-forming process for hard and semi-hard cheeses such as Gouda, the process involves lowering the pH due to lactic acid fermentation and heating to promote the discharge of whey from the curd, followed by molding and pressing to complete the process. The target pH for the whey discharge process is around 5.6, after which the process moves to a cooling process to suppress the vigorous growth of lactic acid bacteria, or to a salting process. Therefore, the target pH for this test was set at 5.6. (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains 217 strains: Lactococcus cremoris 215 strains 527 strain: Lactococcus lactis 527 strain (a milk fermentation starter culture distributed by the Japan Dairy Technology Association) CHN11: CHN11 (A starter culture containing several types of lactic acid bacteria, manufactured by Christian Hansen.) OUT strain: Lactobacillus paracasei OUT0010 strain (Accession number: NITE P-03014) (2) Test method Except for cheese production using the commercially available cheese starter CHN-11, all cheese production was carried out at the dairy processing experimental facility of the National Agriculture and Food Research Organization (NARO) Ikenodai Plant. For Gouda cheese production, four batches were made using strain 527 as the starter, eight batches were made using strain 527 and OUT strain in combination, four batches were made using strain 210 and OUT strain in combination, and four batches were made using strain 215 and OUT strain in combination. The pH of the cheese curd during the production process was measured and recorded over time by measuring the pH of the whey discharged from the cheese curd. In each test group, the average value from the addition of the starter to the raw milk until the pH reached 5.6 was calculated. Gouda cheese production using the commercially available cheese starter CHN-11 was repeated three times at a cheese factory in Hokkaido. Based on the production records, the average time from the addition of the starter to the raw milk until the curd cooled to pH 5.6 was calculated. Figure 7 shows the time (in minutes) it takes for the pH to reach 5.6 after adding the starter to the raw milk. The values ​​labeled with different letters on the bar graph in Figure 7 indicate statistically significant differences at the 5% level in multiple comparison tests using the Tukey-Kramer method.

[0035] As shown in Figure 7, the novel lactic acid bacteria strains 210 and 215 of the present invention were found to exhibit a significantly faster decrease in pH during production compared to strain 527, which has a proven track record as a milk fermentation starter, and the commercially available starter CHN11, in the actual Gouda cheese manufacturing process. This indicates that they have a higher lactic acid production capacity. This demonstrates that the novel lactic acid bacteria in this invention, when used as a starter culture in cheese production, exhibits superior lactic acid production capabilities during the curd molding process, thereby shortening the time required for cheese production. Furthermore, data from Figure 7 showing the results for strain 527 alone, strain 527 + OUT strain, and strain CHN11 alone, and strain CHN11 + OUT strain, confirm that the time (minutes) to reach pH 5.6 does not change significantly. Therefore, it was also confirmed that the lactic acid production capacity does not change significantly even when the OUT strain is used in combination.

[0036] <Example 8: Confirmation test of viable bacterial count in cheese produced with a novel lactic acid bacteria strain> (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains 215 strains: Lactococcus cremoris 215 strains 527 strain: Lactococcus lactis 527 strain (a milk fermentation starter culture distributed by the Japan Dairy Technology Association) OUT strain: Lactobacillus paracasei OUT0010 strain (Accession number: NITE P-03014) (2) Test method The Gouda cheese used for measuring the viable cell count of the starter lactic acid bacteria was produced at the dairy processing experimental facility of the National Agriculture and Food Research Organization (NARO) Ikenodai Plant, vacuum-packed in nylon poly film, and aged in a maturation chamber set at 10°C. For bacterial count measurement, 1g of finely shredded cheese curd was sampled in 50mL of sterilized 2% sodium citrate aqueous solution, suspended in a blender, and then diluted stepwise to create samples. The viable cell counts of strains 210, 215, and 527 were measured on M17 agar plates. The viable cell count of strain OUT0010 was measured on MRS agar plates. Figure 8 shows the number of viable bacteria in Gouda cheese produced using three types of lactic acid bacteria as starter cultures, at different maturation periods (0, 1, 30, 60, 90, 180, and 360 days).

[0037] As shown in Figure 8, the novel lactic acid bacteria strains 210 and 215 of the present invention showed higher viable bacterial counts in cheese throughout the entire maturation period compared to strain 527, which has a proven track record as a milk fermentation starter. Specifically, strain 527 showed a viable bacterial count of 1 × 10⁻⁶. 5 Even in 180-day aged cheese where the cfu / g had decreased to about 1 x 10 8 A viable bacterial count exceeding cfu / g was observed.

[0038] <Example 9: Tasting evaluation test of fermented dairy products produced using a novel lactic acid bacteria strain> Using the novel lactic acid bacterium strain 210 of the present invention, we manufactured a drinkable yogurt and conducted a taste test evaluation. (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains (2) Method for producing and evaluating drinkable yogurt 100 mL of fresh fermented milk was prepared using strain 210 as a starter for production. To 8 liters of pasteurized raw milk, 1% (80 mL) of fermented milk containing fresh strain 210 bacteria and 5% (400 g) of sucrose (based on the weight of the raw milk) were added as a starter and thoroughly mixed. The mixture was then left to ferment in a 30°C incubator for 10 hours. After fermentation, the mixture was cooled in a 10°C refrigerator for approximately 12 hours, then blended to a uniform consistency, filled into containers, and stored refrigerated until evaluation. This was used as the evaluation drinkable yogurt. The taste test evaluation was conducted on the 8th and 9th days after production at three different locations, with evaluators (31 people in total, including staff and students from participating research project institutions) tasting and evaluating the drinkable yogurt. After tasting the drinkable yogurt, each evaluator verbally described what they felt was different from commercially available products they normally consume. The collected responses were compiled as follows to form the evaluation test results. (3) Results Table 5 summarizes the number of respondents and the percentage (%) for each word mentioned by five or more people as a characteristic that differentiated the product from commercially available products. [Table 5]

[0039] As shown in Table 5, 61% of evaluators rated the drinkable yogurt provided for tasting as "easier to drink" than commercially available products. This is likely due to the preferred mild acidity and moderate sweetness, as well as the smooth texture. While typical commercially available drinkable yogurts contain around 5-8% added sugar, approximately 40% of evaluators still described the drinkable yogurt as "sweet." This suggests that the balance with the mild acidity allows the natural sweetness of the milk (lactose) to shine through. This is presumably what the evaluator felt. Furthermore, in this evaluation test, no evaluators provided negative descriptions of the food, such as "unpleasant taste, smell, or texture." These results demonstrate that the novel lactic acid bacterium strain 210 of the present invention is suitable as a starter for fermented milk and various types of yogurt. Drinkable yogurt produced using strain 210 as a starter was found to be as palatable as or even better than commercially available products, with a noticeable sweetness from the raw milk itself, making it an easy-to-drink product.

[0040] <Example 10: Confirmation test of lactic acid production ability of a novel lactic acid bacteria strain 3> In Example 7 above, the results of producing Gouda cheese using the novel lactic acid bacteria strains 210 and 215 of the present invention in combination with the OUT strain were shown. However, when using the novel lactic acid bacteria strains 210 and 215 of the present invention alone as starters, the time it took to reach a specific pH in the Gouda cheese production process was confirmed. The target pH for this test was set at 5.6. Furthermore, the moisture content, fat content, and pH of the Gouda cheese obtained were examined during its maturation period. (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains 215 strains: Lactococcus cremoris 215 strains 527 strain: Lactococcus lactis 527 strain (a milk fermentation starter culture distributed by the Japan Dairy Technology Association) CH1 strain: Lactococcus lactis CH1 strain (a milk fermentation starter culture manufactured by Christian Hansen) (2) Test method Cheese production was carried out at the dairy processing experimental facility of the National Agriculture and Food Research Organization (NARO) Ikenodai Plant. Baby Gouda cheese production was carried out using 16L of raw milk, with strains 210, 215, 527, and CH1 as starter cultures, and the production was repeated three times on different days. Six pieces of baby Gouda cheese were produced per test plot. One piece was provided for test sample preparation at 1, 30, 60, 90, and 180 days of maturation, and was finely chopped with a knife to be used as a sample. The pH of the cheese curd during the production process was measured and recorded over time by measuring the pH of the whey discharged from the cheese curd. For each test plot, the average value from the addition of the starter culture to pH 5.6 was calculated. Figure 9 shows the time (in minutes) it takes for the pH to reach 5.6 after adding the starter to the raw milk. The values ​​labeled with different letters on the bar graph in Figure 9 indicate statistically significant differences at the 5% level in multiple comparison tests using the Tukey-Kramer method. The obtained Gouda cheese was aged at 10°C, and samples were prepared as described above on days 1, 30, 60, 90, and 180 after aging. The moisture content, fat content, pH value, viable cell count, and free amino acid content of the cheese were checked. The manufacturing test was conducted three times, and the average values ​​are shown as the changes over time in Figures 10 to 14. Furthermore, the amount of free glutamic acid (μmol / g) in the cheese after 90 days of aging is shown in Figure 15, and in addition, the glutamic acid concentration (μmol / g) in the cheese on days 1, 30, 60, 90, and 180 after aging is shown in Figure 16.

[0041] As shown in Figure 9, the novel lactic acid bacteria strains 210 and 215 of the present invention showed a significantly faster decrease in pH during production compared to the commercially available CH1 strain, which has a proven track record as a milk fermentation starter, in the actual Gouda cheese production process. Although there was no significant difference compared to the results for strain 527, the pH reached 5.6 within an average of 400 minutes, suggesting extremely high lactic acid production capacity. This demonstrates that the novel lactic acid bacteria in this invention, when used as a starter culture in cheese production, exhibits superior lactic acid production capabilities during the curd molding process, thereby shortening the time required for cheese production. As shown in Figure 10, the moisture content of Gouda cheese produced using the novel lactic acid bacteria strains 210 and 215 of the present invention tended to be higher than that of strains 527 and CH1, which have a proven track record as milk fermentation starters, throughout the entire maturation period. As shown in Figure 11, the fat content in Gouda cheese produced using the novel lactic acid bacteria strains 210 and 215 of the present invention tended to be lower than that of strains 527 and CH1, which have a proven track record as milk fermentation starters, after 60 days of maturation. As shown in Figure 12, the pH values ​​of Gouda cheese produced using the novel lactic acid bacteria strains 210 and 215 of the present invention tended to be equivalent to or lower than those of strains 527 and CH1, which have a proven track record as milk fermentation starters, after 60 days of maturation. The pH of cheeses produced by strains 210 and 215 remained stable from the early stages of maturation, suggesting less variation in quality. As shown in Figure 13, the number of viable bacteria in Gouda cheese produced using the novel lactic acid bacteria strains 210 and 215 of the present invention was confirmed to be higher at all stages of maturation compared to strains 527 and CH1, which have a proven track record as milk fermentation starters, starting from day 60 of maturation. Generally, while natural cheese is a food that allows for the intake of lactic acid bacteria, a problem has been that the number of viable lactic acid bacteria in the cheese decreases rapidly as the maturation period lengthens. However, it has been suggested that this problem can be solved by using the novel lactic acid bacteria strains 210 and 215 of the present invention as starters. As shown in Figure 14, the free amino acid content in Gouda cheese produced using the novel lactic acid bacteria strains 210 and 215 of the present invention, and aged for 90 days (the optimal aging period), showed characteristically high levels of certain components depending on the test group. Cheeses produced by strains 210 and 215 had high levels of glutamic acid (Glu), which contributes to umami, and sarcosine (Sar), which contributes to sweetness, suggesting the possibility of differentiating them from comparative cheeses in terms of taste. Furthermore, cheeses produced by strains 210 and 215 had high levels of branched-chain amino acids (Val, Leu, Ile), which have been shown to maintain muscle function, and imidazole dipeptides (Ans, Car), which have been shown to have anti-fatigue effects, suggesting the possibility of differentiating them from comparative cheeses in terms of functionality. Furthermore, while typical *Lactobacillus cremoris* species do not exhibit arginine deiminase (ADI) activity, and therefore arginine (Arg) is detected as a metabolite, arginine (Arg) was hardly detected in the cheese samples of strains 210 and 215. Instead, citrulline and ornithine, which are converted from arginine (Arg) by ADI, were detected in large quantities. This suggests that strains 210 and 215 are lactic acid bacteria with metabolic enzymes different from typical *Lactobacillus cremoris* species. As shown in Figure 15, the amount of free glutamic acid in Gouda cheese produced using the novel lactic acid bacteria strains 210 and 215 of the present invention, and aged for 90 days (the optimal aging period), was found to be significantly higher compared to strains 527 and CH1, which have a proven track record as milk fermentation starters. This was confirmed to be the amount of free glutamic acid, an amino acid known to constitute the umami flavor of cheese. The values ​​labeled with different letters on the bar graph indicate a statistically significant difference at the 5% level in multiple comparison tests using the Tukey-Kramer method. Similarly, as shown in Figure 16, the free glutamic acid concentration in Gouda cheese produced using the novel lactic acid bacteria strains 210 and 215 of the present invention was confirmed to be higher throughout the entire maturation period compared to strains 527 and CH1, which have a proven track record as milk fermentation starters.

[0042] <Example 11: Confirmation test 1 of fermented butter produced with a novel lactic acid bacteria strain> (1) Tested lactic acid bacteria 210 strains: Lactococcus cremoris 210 strains 217 strains: Lactococcus cremoris 215 strains Ll23 strain: Lactococcus lactis Ll-23 strain (manufactured by Danisuco) (2) Test method Butter was produced using commercially available fresh cream (Yotsuba Pure Fresh Cream NH47, 47% milk fat). Fat granules and buttermilk were prepared from the cream using a food processor (TESCOM) equipped with a butter preparation unit. After removing the buttermilk, the fat granules were washed twice with cold water, and the resulting fat granules were kneaded using a reverse sheeter (Nippon Kneader Co., Ltd.). The weight of the resulting butter was measured, and freeze-dried strains of each type of lactic acid bacteria were added to ensure the same bacterial count per unit weight. Further kneading was then performed. These were filled into cups and incubated at 20°C for two days. A control sample prepared in the same manner without the addition of lactic acid bacteria was used. Each fermented butter was prepared three times, and the number of lactic acid bacteria, pH value, general components such as water content and fat content, and aromatic components were analyzed using the analytical method described below. Table 6 shows the average number of lactic acid bacteria and pH value in fermented butter, Table 7 shows the average moisture content and fat content in fermented butter, and Table 8 shows the average aromatic component value in fermented butter. Each of the obtained values ​​was subjected to multiple comparison testing using the Tukey-Kramer method. Values ​​with different letters in Tables 6-8 indicate a statistically significant difference at the 5% level between the test intervals.

[0043] (3) Method for analyzing aromatic components Each fermented butter was prepared by adding 3-octanol as an internal standard, and GC-MS analysis was performed using solid-phase microextraction (SPME). The relative area ratio of the peak area of ​​each aromatic component to the peak area of ​​the internal standard was calculated. The values ​​in Tables 8 and 9 represent the mean ± standard deviation of three preparations for each fermented butter. <Solid-phase microextraction (SPME)> SPME type: 50 / 30μm DVB / CAR / PDMS (Merck) Sample incubation: 50°C, 30 minutes Adsorption: 50°C, 30 minutes <gc-ms> ·GC equipment, analysis conditions Equipment: GC-2010 (manufactured by Shimadzu Corporation) Injection: Splitless Inlet: 250℃ Sampling time: 300 seconds Gas: Helium Column: HP-INNOWax (60m x 0.25mm, 0.25μm) Column flow rate: 1.0 mL / min Column temperature program: Hold at 40°C for 5 minutes → Heating rate 4°C / min → Hold at 220°C for 10 minutes (Total 60 minutes) ·MS equipment, analysis conditions Equipment: GCMS-QP2010 (manufactured by Shimadzu Corporation) Interface: 250℃ Ion source: 230℃ Measurement mode: Scan (40.00~350.00 m / z) Energy: 70 eV

[0044] [Table 6]

[0045] [Table 7]

[0046] [Table 8]

[0047] As shown in Tables 6 and 7, no significant differences were observed in the moisture content and fat content of the fermented butter produced. Furthermore, no differences were found in the number of lactic acid bacteria in the fermented butter. On the other hand, the pH value of the fermented butter was significantly lower in the butter prepared using strain 210 compared to the butter prepared using the commercially available strain L123, and tended to be lower in the butter prepared using strain 215. These findings demonstrate that the novel lactic acid bacteria strains 210 and 215 of the present invention exhibit higher acid-producing ability than the commercially available strain L123, even in butter, which is a W / O type emulsion with low water content, and are suitable for preparing fermented butter that suppresses the growth of unwanted bacteria at low pH. Furthermore, as shown in Table 8, when comparing the proportions of diacetyl and acetoin, which are the main aromatic components of fermented butter, no significant difference was observed in diacetyl outside of the control and test intervals. However, the proportion of acetoin was significantly higher in strain 215 compared to strain 210, and strain 210 tended to have a lower proportion compared to the commercially available strain Ll23, while strain 215 tended to have a higher proportion. Since the intensity of these aromas affects palatability, it was suggested that by using the two novel lactic acid bacteria strains of the present invention in a selective manner, it is possible to manufacture products that meet customer needs.

Claims

1. Lactic acid bacteria that are Lactococcus cremoris strain 210 (accession number: NITE P-04049) or Lactococcus cremoris strain 215 (accession number: NITE P-04050).

2. The lactic acid bacteria according to claim 1, characterized in that it is used for the manufacture of dairy products.

3. The lactic acid bacteria according to claim 1, characterized in that it is used as a cheese starter culture.

4. A dairy product containing the lactic acid bacteria described in any one of claims 1 to 3.

5. A cheese containing the lactic acid bacteria described in any one of claims 1 to 3.

6. A method for producing dairy products, characterized by using the lactic acid bacteria described in any one of claims 1 to 3.

7. A method for producing cheese, characterized by using the lactic acid bacteria described in any one of claims 1 to 3.

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