Sausage making method capable of effectively controlling dry-heat-resistant salmonella

Abstract

The invention discloses a method for making sausages capable of effectively controlling dry heat-resistant salmonella, which comprises the following steps of: 1, inoculating lactobacillus rhamnosus into seasoned meat paste, and adding 5-6mL of 1 * 10 < 6 >-1 * 10 < 8 > CFU / ml lactobacillus rhamnosus liquid into every 100g of meat; step 2, filling the inoculated meat paste into a casing to obtain a sausage semi-finished product; step 3, fermenting the sausage semi-finished product for 29-31 hours under the condition of 30-40 DEG C, and stopping fermentation when the pH value is reduced to 5.3-5.1; step 4, carrying out smoking treatment on the fermented sausage semi-finished product in smoking equipment at 59-61 DEG C for 40-50 minutes, detecting the water activity, and controlling the water activity to be lower than 0.6; and 5, stopping smoking, and airing to normal temperature to obtain a sausage finished product. According to the sausage prepared by the preparation method disclosed by the invention, good fermentation flavor and sausage quality are maintained, and meanwhile, the dry-heat-resistant salmonella in the sausage can be effectively controlled.

Description

Technical Field

[0001] The invention belongs to a fermented meat food processing technology, in particular to a sausage making method for effectively controlling dry heat resistant Salmonella. Background Art

[0002] Salmonella is one of the main causes of most food poisoning. Food contaminated by Salmonella will not have obvious changes in appearance or smell, making it difficult to detect that the food is contaminated by Salmonella.

[0003] In recent years, food poisoning incidents caused by Salmonella in low water activity foods have occurred frequently. Salmonella has high environmental tolerance and can withstand extreme environments such as dryness and high temperature. Although heat treatment has long been regarded as the main method of food preservation and effectively eliminates most foodborne pathogens, Salmonella can survive the food processing process. This survival ability, especially in low water activity foods, has attracted widespread attention. Studies have found that as the water activity (aw value) of food decreases, the survival rate and heat resistance of Salmonella will increase. For example, Salmonella in peanut butter is very heat-resistant, and even at a temperature of up to 90°C, it only reduces by 3.2 CFU / g. The results of the study on the heat resistance of Salmonella in wheat flour showed that when the aw level decreased, the D value increased significantly. The D value was 165 min at 70°C and aw of 0.25-0.30, while the D value was 80 min at 70°C and aw of 0.50-0.60. Therefore, how to achieve efficient killing of dry heat-resistant Salmonella in low water activity foods is a major challenge in the current field of disinfection and sterilization technology.

[0004] Lactic acid bacteria are reported to be a potential alternative to antibiotics for combating pathogens. Lacticaseibacillus rhamnosus. ) can be used as a probiotic to inhibit pathogenic bacteria. The antimicrobial compounds produced by it can significantly inhibit the growth and migration of pathogenic strains, as well as the formation of biofilms, membrane destruction and the generation of reactive oxygen species. It has broad application prospects as a fermentation agent or probiotic. However, at present, Lactobacillus rhamnosus has no effect on the growth of Salmonella enterica subspecies infantis serotype ( S. There is no clear report on the inhibitory effect on pathogenic bacteria strains with strong dry heat resistance, such as Infantis CICC21649. Summary of the invention

[0005] The purpose of the present invention is to provide a sausage production method using Lactobacillus rhamnosus to effectively control dry heat-resistant Salmonella, so as to solve the problem that in the production process of fermented sausages in the prior art, even after heating treatment, a high proportion of Salmonella strains still survive and cannot be effectively reduced to safety standards. The purpose of the present invention is achieved through the following technical solutions: A sausage making method for effectively controlling dry heat resistant Salmonella comprises the following steps: Step 1: Inoculate the seasoned minced meat with Lactobacillus rhamnosus. Add 5-6 mL of 1×10 6 ~1×10 8 CFU / ml of Lactobacillus rhamnosus culture; Step 2: filling the inoculated minced meat into casings to obtain a semi-finished sausage product, wherein the initial pH value of the meat of the semi-finished sausage product is pH 6.0-pH 5.8; Step 3: ferment the semi-finished sausage at 30°C to 40°C for 29 to 31 hours, with a relative humidity of 85%, and stop fermentation when the pH value drops to pH 5.3 to pH 5.1; Step 4: Smoke the fermented sausage semi-finished product in a smoking device at 59-61°C for 40-50 minutes, detect the water activity, and control the water activity to be less than 0.6; Step 5: Stop smoking and let the sausage air dry to room temperature to obtain the finished sausage.

[0006] The dry heat resistant Salmonella is a Salmonella that can survive in a matrix at 60°C and a water activity of less than 0.6. The dry heat resistant Salmonella includes the enterica subspecies infantis serotype S . Infantis CICC21649.

[0007] Further optimization, the Lactobacillus rhamnosus Lacticaseibacillus rhamnosus The gene includes an upstream sequence as shown by SEQ ID NO.1 and a downstream sequence as shown by SEQ ID NO.2.

[0008] Furthermore, in step 1, 5 mL of 1×10 8 CFU / ml of bacterial solution.

[0009] Furthermore, in step 1, the Lactobacillus rhamnosus bacterial liquid is prepared using MRS buffer.

[0010] Furthermore, in step 2, the initial pH value of the semi-finished sausage meat is pH 6.0.

[0011] Furthermore, in step three, the semi-finished sausage product is fermented at 30° C. for 30 hours.

[0012] Furthermore, in step 4, the fermented semi-finished sausage product is smoked in a smoking device at 60° C. for 45 minutes.

[0013] Analysis of technical difficulties and creativity in the development process of this invention: The present invention has two technical difficulties in the research and development process. First, in the existing literature, the antibacterial effect of Lactobacillus rhamnosus is usually carried out in a liquid fermentation environment, and in an environment of low water activity, its metabolic activity may be restricted. Low water activity can inhibit the growth and reproduction of microorganisms, thereby may reduce the generation of metabolites of Lactobacillus rhamnosus, and these metabolites are often the key to the antibacterial effect. Second, heat treatment may affect the survival ability and antibacterial effect of Lactobacillus rhamnosus through approaches such as cell membrane damage, protein denaturation, DNA damage. Under dry conditions, because the water activity is relatively low, the heat conduction effect in the cell can be reduced, so that Lactobacillus rhamnosus may have a certain degree of heat resistance, but with the extension of the processing time, its viable count may still decline significantly, thereby causing its antibacterial effect to weaken.

[0014] Based on the above two points, it is uncertain whether the application of Lactobacillus rhamnosus to the treatment of smoked fermented sausages can have a significant effect on controlling Salmonella. Therefore, it is necessary to explore and improve various parameters of the sausage production process to finally obtain the technical solution of the present invention.

[0015] The advantages and beneficial effects of the present invention are: 1) The present invention is the first to apply Lactobacillus rhamnosus to kill Salmonella in low water activity food matrix. The selection of Lactobacillus rhamnosus is creative, and the inhibitory effect of this bacterium on Salmonella during food drying-heat treatment is still unclear.

[0016] 2) The method of the present invention can effectively reduce the dry heat resistance of Salmonella. After adding a certain concentration of Lactobacillus rhamnosus and undergoing dry heat treatment during smoking under certain conditions, the number of dry heat-resistant Salmonella colonies in the fermented sausage can be reduced by about 4.4 log (CFU / g).

[0017] 3) The sausages prepared by the method of the present invention not only effectively control the dry heat-resistant Salmonella, but also maintain good fermentation flavor and sausage quality.

[0018] 4) The materials used in the method of the present invention, such as Lactobacillus rhamnosus, are inexpensive, the preparation and use methods are simple, and the requirements for technical personnel are low, so the method is suitable for large-scale adoption by food processing enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] Figure 1 The experimental results of Example 1 and Comparative Example 1 are compared.

[0021] Figure 2 is the tolerance of 12 strains of Salmonella to heat treatment under dry conditions (aw≤0.3); Figure 2 A: aw≤0.3, lethality of strain after dry heat treatment at 60℃ for 1 h; Figure 2 B: aw≤0.3, lethality of strains after dry heat treatment at 80℃ for 1 h. DETAILED DESCRIPTION

[0022] The present invention is further described below by way of embodiments and comparative examples: Embodiment 1: The preparations before making sausages include: 1) Prepare MRS and TSB buffer.

[0023] 2) Inoculate Lactobacillus rhamnosus (Lactobacillus rhamnosus Lacticaseibacillus rhamnosus. All of them are from the Chinese Academy of Agricultural Sciences. The gene of the Lactobacillus rhamnosus strain in this example includes the upstream sequence shown in SEQ ID NO.1 and the downstream sequence shown in SEQ ID NO.2), until the number of Lactobacillus rhamnosus is 1×10 8 CFU / mL, and obtain rhamnosus bacterial liquid.

[0024] 3) Inoculate the prepared TSB buffer with Salmonella strains (Salmonella was purchased from the China Industrial Microbiological Culture Collection Management Center) until the number of Salmonella is 1×10 9 CFU / mL, and obtain the Salmonella liquid.

[0025] The sausage making method for effectively controlling dry heat resistant Salmonella comprises the following steps: Step 1: adding the above-mentioned Lactobacillus rhamnosus liquid to the seasoned minced meat, adding 5 mL of Lactobacillus rhamnosus liquid to every 100 g of meat; adding 5 mL of Salmonella liquid to every 100 g of meat in the experimental group; and adding 5 mL of deionized water to every 100 g of meat in the control group instead of the Salmonella liquid; Step 2: filling the inoculated minced meat into sausage casings to obtain a semi-finished sausage product, wherein the initial pH value of the semi-finished sausage product is pH 6.0; Step 3: ferment the semi-finished sausage at 30°C for 30 hours, with a relative humidity of 85%, and stop fermentation when the pH value drops to pH 5.3; Step 4: Smoke the fermented sausage semi-finished product in a smoking device at 60°C for 45 minutes, detect the water activity, and control the water activity to be less than 0.6; Step 5: Stop smoking and let the sausage air dry to room temperature to obtain the finished sausage.

[0026] The sausages were subsequently subjected to colony culture and total number detection of Salmonella. Colony culture specifically includes gradient dilution, plating and culture, and the culture medium used is TSB culture medium. After the plate is placed in a 37°C incubator for 24 hours, the colony count is performed to calculate the number of Salmonella colonies in the original sample.

[0027] The flavor of the sausage is normal, and the control effect of this processing method on Salmonella is within the safe range of foodborne pathogens.

[0028] Comparative Example 1 Compared with Example 1, the comparative example is different from Example 1 only in that in step 1, the Lactobacillus rhamnosus bacterial solution is not inoculated, but an equal amount of deionized water is inoculated. The other operations are the same as those in Example 1.

[0029] The results of Example 1 and Comparative Example 1 show that: 8 CFU / mL of Lactobacillus rhamnosus can significantly reduce the number of Salmonella colonies. Specifically, after dry heat treatment, the samples with Lactobacillus rhamnosus added showed a decrease in the number of dry heat-resistant strains compared to the samples without Lactobacillus rhamnosus. S . Infantis CICC21649 strain, sensitive strain S . Hadar CICC21594 strain, sensitive strain S The reductions of Miami CICC21509 were 4.48 log CFU / g, 4.40 log CFU / g and 4.49 log CFU / g respectively. Figure 1 As shown, the left side is the result of comparative example 1, and the right side is the result of embodiment 1.

[0030] Comparative Example 2 This comparative example is different from Example 1 only in step 3, and other operations are the same as Example 1.

[0031] Step 3: Ferment the semi-finished sausage at 30°C for 20 hours, with a relative humidity of 85%, and stop fermentation when the pH value drops to pH 5.7.

[0032] The results of this comparative example test were as follows: dry heat resistant strains S . Infantis CICC21649 strain, sensitive strain S . Hadar CICC21594 strain, sensitive strain S . Miami CICC21509 increased compared to Example 1, with the increase value exceeding 1 log CFU / g. In addition, the fermentation flavor was lighter and the sourness was insufficient.

[0033] It can be seen that a lower pH helps inhibit the growth of pathogens and gives fermented sausages a unique sour taste.

[0034] Comparative Example 3 This comparative example is different from Example 1 only in step 4, and other operations are the same as Example 1.

[0035] Step 4: Smoke the fermented sausage semi-finished product in a smoking device at 80°C for 45 minutes, and detect the water activity, which is below 0.6; The results of the comparative test were as follows: sensitive strains S . Hadar CICC21594 strain and sensitive strain S. Miami CICC21509 decreased compared with Example 1, but the difference was not significant. S . The Infantis CICC21649 strain showed no obvious changes.

[0036] Example 2 A sausage making method for effectively controlling dry heat resistant Salmonella: Step 1: Inoculate the above-mentioned Lactobacillus rhamnosus liquid into the seasoned minced meat, adding 5mL10 8 CFU / mL Lactobacillus rhamnosus liquid; Step 2: filling the inoculated minced meat into sausage casings to obtain a semi-finished sausage product, wherein the initial pH value of the meat of the semi-finished sausage product is pH 6.0; Step 3: ferment the semi-finished sausage at 33°C for 31 hours, with a relative humidity of 85%, and stop fermentation when the pH value drops to pH 5.1; Step 4: Smoke the fermented sausage semi-finished product in a smoking device at 60°C for 45 minutes, detect the water activity, and control the water activity to be less than 0.6; Step 5: Stop smoking and let the sausage air dry to room temperature to obtain the finished sausage.

[0037] The sausages were subsequently subjected to colony culture and total number detection of Salmonella. Colony culture specifically includes gradient dilution, plating and culture, and the culture medium used is TSB culture medium. After the plate is placed in a 37°C incubator for 24 hours, the colony count is performed to calculate the number of Salmonella colonies in the original sample.

[0038] The flavor of the sausage is normal, and the control effect of this processing method on Salmonella is within the safe range of foodborne pathogens.

[0039] Example 3 A sausage making method for effectively controlling dry heat resistant Salmonella: Step 1: Inoculate the above-mentioned Lactobacillus rhamnosus liquid into the seasoned minced meat, adding 5.5mL10 7 CFU / mL Lactobacillus rhamnosus liquid; Step 2: filling the inoculated minced meat into casings to obtain a semi-finished sausage product, wherein the initial pH value of the meat of the semi-finished sausage product is pH 5.8; Step 3: ferment the semi-finished sausage at 30°C for 30 hours, with a relative humidity of 85%, and stop fermentation when the pH value drops to pH 5.2; Step 4: Smoke the fermented sausage semi-finished product in a smoking device at 61°C for 42 minutes, detect the water activity, and control the water activity to be less than 0.6; Step 5: Stop smoking and let the sausage air dry to room temperature to obtain the finished sausage.

[0040] The sausages were subsequently subjected to colony culture and total number detection of Salmonella. Colony culture specifically includes gradient dilution, plating and culture, and the culture medium used is TSB culture medium. After the plate is placed in a 37°C incubator for 24 hours, the colony count is performed to calculate the number of Salmonella colonies in the original sample.

[0041] The flavor of the sausage is normal, and the control effect of this processing method on Salmonella is within the safe range of foodborne pathogens.

[0042] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred arrangement scheme, a person skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A sausage making method for effectively controlling dry heat resistant Salmonella, characterized in that: The following steps are involved: Step 1: Inoculate the seasoned minced meat with Lactobacillus rhamnosus. Add 5-6 mL of 1×10 6 ~1×10 8 CFU / ml of Lactobacillus rhamnosus culture; Step 2: filling the inoculated minced meat into sausage casings to obtain a semi-finished sausage product, wherein the initial pH value of the semi-finished sausage product is pH 6.0-pH 5.8; Step 3: ferment the semi-finished sausage at 30°C to 40°C for 29 to 31 hours, with a relative humidity of 85%, and stop fermentation when the pH value drops to pH 5.3 to pH 5.1; Step 4: Smoke the fermented sausage semi-finished product in a smoking device at 59-61°C for 40-50 minutes, detect the water activity, and control the water activity to be less than 0.6; Step 5: Stop smoking and let the sausage air dry to room temperature to obtain the finished sausage.

2. The sausage making method according to claim 1, characterized in that: The dry heat resistant Salmonella is a Salmonella that can survive in a matrix at 60° C. and with a water activity of less than 0.

6.

3. The sausage making method according to claim 1, characterized in that: The dry heat resistant Salmonella includes Salmonella enterica subspecies infantis serotype S . Infantis CICC21649.

4. The sausage making method according to claim 1, characterized in that: Lactobacillus rhamnosus Lacticaseibacillus rhamnosus The gene includes an upstream sequence shown by SEQ ID NO.1 and a downstream sequence shown by SEQ ID NO.

2.

5. The sausage making method according to claim 1, characterized in that: In step 1, add 5 mL of 1×10 8 CFU / ml of bacterial solution.

6. The sausage making method according to claim 1, characterized in that: In step 1, the Lactobacillus rhamnosus bacterial liquid is prepared using MRS buffer.

7. The sausage making method according to claim 1, characterized in that: In step 2, the initial pH value of the semi-finished sausage meat is pH 6.

0.

8. The sausage making method according to claim 1, characterized in that: In step 3, the semi-finished sausage product is fermented at 30° C. for 30 hours.

9. The sausage making method according to claim 1, characterized in that: In step 4, the fermented semi-finished sausage is smoked in a smoking device at 60° C. for 45 minutes.

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