A broad-spectrum lytic salmonella saint-paulis bacteriophage, composition and use thereof

Abstract

The present application relates to the field of microbial technology, and particularly relates to a broad-spectrum lytic Salmonella sp. phage, a composition and application thereof. The phage is preserved in the China General Microbiological Culture Collection Center, and the preservation number is CGMCC No. 45281. The phage is isolated from a strain of Salmonella sp., and the core advantage is that (1) it has super-broad-spectrum lytic activity, and can efficiently lyse at least 11 important Salmonella serotypes such as Salmonella enteritidis and Salmonella typhimurium; (2) it has excellent physicochemical stability, and can still maintain high activity after being treated at pH 4-11 and 60 DEG C for 1 hour. Based on the above characteristics, the present application further provides a composition containing the phage, and application thereof in preparing products for food surface disinfection and preservation and prevention and treatment of livestock Salmonella infection. The phage of the present application solves the problems of narrow host spectrum, poor stability and single application scene in the prior art.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, specifically to a broad-spectrum lytic Salmonella São Paulo bacteriophage, its composition, and its applications. Background Technology

[0002] salmonella (Salmonella Saintpaul) Salmonella is a significant foodborne pathogen that can cause gastroenteritis, sepsis, and even death in humans. Among its serotypes are *Salmonella staunchauensis*, *Salmonella enteritidis*, and *Salmonella typhimurium*, which are common causes of food poisoning outbreaks. These pathogens frequently contaminate poultry products and fresh produce (such as lettuce and tomatoes), posing a serious threat to public safety.

[0003] Currently, controlling Salmonella mainly relies on antibiotics and chemical disinfectants. However, the overuse of antibiotics has led to the emergence and spread of drug-resistant strains, while chemical disinfectants pose problems such as residues, disruption of the microecological environment, and environmental pollution.

[0004] Bacteriophages, as viruses capable of specifically lysing bacteria, are considered a potential alternative to antibiotics due to their high specificity, self-replication ability, and environmental friendliness.

[0005] However, existing Salmonella phage technologies have significant limitations: 1. Narrow host spectrum: Most phages target only a single or a few serotypes, making it difficult to cope with mixed contamination of multiple Salmonella species in real-world environments. While "cocktail" phage formulations can broaden the lysis spectrum, they increase preparation costs and the complexity of quality control. 2. Poor environmental stability: Many bacteriophages have poor tolerance to extreme pH and temperature, which limits their application in special environments such as acidic fruit and vegetable surfaces or poultry gastrointestinal tracts; 3. Limited application scenarios: Existing phage preparations are usually designed for a single scenario (such as only for food surface disinfection or only for animal treatment), lacking a comprehensive solution that can cover multiple stages from farm to table.

[0006] Therefore, isolating a Salmonella phage with broad-spectrum lytic activity, excellent environmental stability, and good safety is of great significance for promoting the practical application of phage technology.

[0007] The information disclosed in this background section is only intended to enhance the understanding of the background technology of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a Salmonella phage with broad-spectrum lytic activity, excellent environmental stability, and good safety, as well as its composition and applications.

[0009] The technical solution of this invention is as follows: On the one hand, this invention provides a broad-spectrum lytic Salmonella phage of St. Paul (… Salmonella Saintpaul bacteriophage The accession, named RDP-SA-21032, was deposited on September 21, 2022, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 45281.

[0010] Furthermore, the St. Paul's Salmonella phage is capable of lysing at least three serotypes of Salmonella St. Paul's, Salmonella Enteritidis, Salmonella Typhimurium, Salmonella Indiana, Salmonella Kentucky, Salmonella Delphi, Salmonella Stanley, Salmonella Schuvachenko, Salmonella Agona, Salmonella Nevtenberg, and Salmonella Subrae.

[0011] Furthermore, the St. Paul's Salmonella phage is capable of lysing St. Paul's Salmonella, Salmonella enteritidis, Salmonella typhimurium, Salmonella Indiana, Salmonella Kentucky, Salmonella Delphi, Salmonella Stanley, Salmonella Schovanlos, Salmonella Argonne, Salmonella Nevtenberg, and Salmonella Subrae.

[0012] Furthermore, the activity of the Salmonella St. Pauli bacteriophage remained above 90% after treatment in a buffer solution of pH 4-11 for 1 hour; and after treatment in a buffer solution of pH 3 or pH 12 for 1 hour, its activity remained above 50%.

[0013] Furthermore, the titer of the Salmonella St. Pauli bacteriophage decreased by less than 1 log unit after treatment in a 60°C water bath for 1 hour.

[0014] Furthermore, the highest titer of the *S. Paulus* phage was observed at a multiplicity of infection (MCI) of 0.1, reaching 1.3 × 10⁻⁶. 10 pfu / mL.

[0015] On the other hand, the present invention provides a composition comprising an effective amount of the above-mentioned Salmonella St. Pauli bacteriophage, and a food- or pharmaceutically acceptable carrier.

[0016] On the other hand, the present invention provides the use of the above-mentioned Salmonella St. Pauli bacteriophage or composition in the preparation of products for food surface disinfection or food preservation.

[0017] Furthermore, the food is vegetables, fruits, meat, or poultry eggs.

[0018] On the other hand, the present invention provides the use of the above-mentioned Salmonella St. Pauli bacteriophage or composition in the preparation of products for the prevention or treatment of Salmonella infection in livestock and poultry.

[0019] Furthermore, the product is a drinking water additive or a treatment agent for livestock and poultry.

[0020] Furthermore, the livestock and poultry mentioned are broiler chickens.

[0021] On the other hand, the present invention provides a complete kit for the prevention and control of Salmonella in the livestock and poultry farming to food processing chain, comprising: The first formulation, comprising the aforementioned Salmonella St. Pauli bacteriophage or composition, is intended for use on livestock and poultry; and The second formulation, comprising the above-mentioned Salmonella St. Pauli bacteriophage or composition, is used for application to the surface of food. The São Paulo Salmonella phage in the first and second formulations is the same strain.

[0022] The beneficial effects achieved by this invention are as follows: 1. The bacteriophage provided by this invention, isolated from a single strain of Salmonella St. Pauli as the host, exhibits highly efficient lysis against up to 11 important pathogenic Salmonella serotypes, including Salmonella Enteritidis and Salmonella Typhimurium, with a lysis rate of 100% against Salmonella Enteritidis. This characteristic allows a single strain to replace the traditional "cocktail" formulations that require mixing multiple bacteriophages, fundamentally solving the problems of complex formulations, high costs, and difficult quality control caused by a narrow host spectrum. It provides an extremely simple and efficient single biological solution for dealing with mixed Salmonella contamination in real-world environments. 2. The bacteriophage of this invention retains over 90% of its activity after treatment for 1 hour within a wide pH range of 4-11, and its titer decreases by less than 1 log unit after 1 hour of high-temperature treatment at 60°C. This characteristic enables it to exist stably on the surfaces of acidic fruits and vegetables (such as tomatoes and lettuce) and in the complex acid-base environment of the poultry gastrointestinal tract, solving the technical bottleneck of conventional bacteriophages' inability to maintain activity in these key application scenarios and greatly expanding its applicable boundaries. 3. Based on the aforementioned superior broad-spectrum and stability, this invention is the first to achieve the use of a single bacteriophage strain to cover multiple key stages of Salmonella control. Specifically, the bacteriophage of this invention can be used both in the livestock and poultry breeding stage (through drinking water or feed addition to prevent and treat infection, reduce intestinal colonization and product contamination) and directly in the post-harvest food processing stage (through spraying or soaking to efficiently disinfect and preserve the surface of fruits, vegetables, poultry, and other foods). This breaks with the convention of existing bacteriophage products typically designed for only a single scenario, providing a coherent biological control strategy that runs through the entire production chain, truly achieving full-chain risk control from source to end. 4. The bacteriophage and application scheme provided by this invention overcome the problems of drug resistance, drug residues and environmental pollution caused by antibiotics and chemical disinfectants, and is a highly safe and green new biological control tool. Attached Figure Description

[0023] Figure 1 This is a phage plaque diagram of Salmonella São Paulo in this invention.

[0024] Figure 2 This is an electron micrograph of the Salmonella São Paulo phage from this invention.

[0025] Figure 3 This is a one-step growth curve of the Salmonella St. Pauli bacteriophage in this invention.

[0026] Figure 4 This is the pH stability curve of the Salmonella St. Pauli bacteriophage in this invention.

[0027] Figure 5 This is the temperature stability curve of the Salmonella St. Pauli bacteriophage in this invention.

[0028] Figure 6 This is a graph showing the results of the live Salmonella count on the surface of tomatoes in Example 8. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In this invention, unless otherwise specified, the equipment and raw materials used are commercially available or commonly used in the art. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0031] In this invention, Salmonella São Paulo BS-21052 is referred to as host 21052 or 21052, and Salmonella São Paulo phage RDP-SA-21032 is referred to as phage RDP-SA-21032 or RDP-SA-21032.

[0032] Example 1: Isolation and purification of Salmonella stolonifera bacteriophage in St. Paul 1.1 Sample source: Wastewater samples were collected from a large chicken farm in Shandong Province.

[0033] 1.2 Host Bacteria: Liver samples from diseased poultry were aseptically collected and streaked onto Salmonella chromogenic selective medium. After incubation at 37°C for 24 hours, round, flat, smooth-edged, moist, pale purple colonies formed on the medium. Typical colonies were picked and streaked five more times for purification. A single colony was then inoculated into 5 mL of LB broth and incubated at 37°C with shaking at 200 rpm for 6 hours, yielding a homogeneous, turbid bacterial suspension. 16S rRNA molecular identification confirmed it as Salmonella. Serotype was determined by PCR identification of the O antigen (primer information is shown in Table 1 below) and serum agglutination assay, identifying it as *Salmonella S. Paulo* (serotype identification results are shown in Table 2 below), named BS-21052, and stored at -80°C.

[0034] Table 1. Primer information for Salmonella Group B identification

[0035] Table 2. Salmonella serotype identification results

[0036] 1.3 Phage enrichment and isolation: Enrichment: Centrifuge the wastewater sample at 10,000 rpm for 5 min, filter the supernatant through a 0.22 μm filter, and mix it with the exponential phase culture of the host bacteria: 100 μL of host bacteria and 1 mL of wastewater were added to 10 mL of LB liquid medium and cultured at 37°C and 180 rpm for 16 h with shaking. Isolation: After filtering the culture through a 0.22 μm filter membrane, the filtrate was used for plaque screening using the double-layer agar plate method. Figure 1 As shown; Purification and preparation: Select single, clearly morphologically clear, and transparent plaques and repeat the streak purification process at least three times until a purified phage suspension is obtained, named RDP-SA-21032. Mix the phage suspension with 60% glycerol + LB at a 1:1 ratio and store in liquid nitrogen.

[0037] 1.4 Phage titer determination: The phage suspension was serially diluted 10-fold, and the titer was determined using the double-layer agar plate method, with a value of 2.0 × 10^6. 10 pfu / mL.

[0038] 1.5 Biological characteristics of Salmonella stolonifera bacteriophage in St. Paul Morphological identification: 20 μL of liquid containing crude phage particles was dropped onto a copper grid and allowed to settle naturally for 15 min. Excess liquid was then removed from the side with filter paper. One drop of 2% phosphotungstic acid (PTA) was added to the copper grid to stain the phage for 10 min. The staining solution was then removed from the side with filter paper. After the sample dried, the morphology of the phage was observed using an electron microscope. The morphology of the phage particles was observed using a transmission electron microscope.

[0039] The results are as follows Figure 2 The head is approximately spherical (actually an icosahedral symmetry structure), with a diameter of about 80-100 nm according to the scale bar. Under an electron microscope, due to the high density of internal genetic material (DNA or RNA), it has a strong ability to scatter electron beams, appearing as a dense black or dark gray area in the image, contrasting sharply with the background and tail. The tail is a slender tubular structure connected to one end of the head, and its total length (from the connection point to the end) significantly exceeds the diameter of the head, estimated to be about 150-200 nm. Its aspect ratio (tail length / head diameter) is approximately between 1.5:1 and 2:1. Its protein structure has a relatively low density, appearing as light gray and almost translucent in the image. The tail structure is complex, typically containing subunits such as a tail sheath, tail tube, basement membrane, and tail filaments (which may not be fully distinguishable at this resolution). It belongs to the family Longtail Phageidae.

[0040] Example 2: Determination of phage lysis profiles of Salmonella São Paulo 2.1 Experimental Methods The lytic activity against multiple serotypes of Salmonella (including Salmonella enteritidis, Salmonella typhimurium, Salmonella Indiana, Salmonella delphini, Salmonella Argonnae, Salmonella Nevtenberg, Salmonella schoenleinii, and Salmonella subbranchi) and non-Salmonella (such as Escherichia coli and Staphylococcus aureus) was determined using the spot method.

[0041] 2.2 Experimental Results and Analysis Table 3: Results of phage lysis profile determination of Salmonella São Paulo (All strains listed below are laboratory isolated strains)

[0042] Fracturing spectrum results table: Note: +++ indicates strong fracturing ability, ++ indicates moderate fracturing ability, + indicates weak fracturing ability, - indicates no fracturing.

[0043] As shown in Table 3, this strain of Salmonella São Paulo phage can effectively lyse 11 important Salmonella serotypes, including the host bacterium, but has no lysing activity against non-Salmonella bacteria, demonstrating the specificity of its lysed Salmonella and its broad spectrum of different species.

[0044] Example 3: Determination of the optimal multiplicity of infection for Salmonella São Paulo bacteriophage 3.1 Experimental Methods Phage proliferation solution and host were added to LB broth at ratios of 100, 10, 1, 0.1, and 0.01, ensuring that the total volume of the culture system was the same. After incubation at 37°C with shaking at 200 rpm for 8 h, the mixture was centrifuged at 12000 rpm for 5 min at room temperature, and the supernatant was plated on double plates to determine its potency.

[0045] 3.2 Experimental Results and Analysis Table 4: Results of Determination of Optimal Multiplicity of Infection

[0046] As shown in Table 4, when the multiplicity of infection (MCI) was 0.1, the proliferation medium was clearer and the titer was highest (1.3 × 10⁻⁶) after 8 hours of culture. 10 The pfu / mL indicates that the optimal multiplicity of infection for bacteriophages is 0.1.

[0047] Example 4: One-step growth curve of Salmonella São Paulo bacteriophage 4.1 Experimental Methods Take a suspension of *E. coli* in the logarithmic growth phase, inoculate the host bacteria and bacteriophages at the optimal multiplicity of infection ratio, incubate in a water bath at 37°C for 10 min, then centrifuge at 12000 rpm / min for 5 min at room temperature, discard the supernatant to remove free bacteriophages not adsorbed onto the host, and wash twice with LB liquid medium. Resuspend the precipitate in LB broth at 37°C, and immediately place it in a shaker at 37°C and 200 rpm for incubation, timing the process. Sampling and counting are performed every 5 min for the first 40 min, every 10 min from 40-60 min, and every 30 min from 60-300 min. A growth curve is plotted with time on the x-axis and the logarithmic value of the bacteriophage titer on the y-axis to determine the phage latency and lysis period, and the average lysis rate is calculated.

[0048] The average lysis rate is calculated as: phage titer at the end of the outbreak / host bacterial concentration at the beginning of infection.

[0049] 4.2 Experimental Results and Analysis like Figure 3 As shown, the phage has a latency period of approximately 20 minutes, an outbreak period of approximately 30 minutes, and an average lysis yield (phage titer at the end of the outbreak / host bacterial concentration at the beginning of infection) of approximately 125 PFU / cell. This indicates that it has a short proliferation cycle and high proliferation efficiency.

[0050] Example 5: pH stability of Salmonella phage from St. Paul 5.1 Experimental Methods The phage suspensions were placed in buffer solutions with pH values ​​ranging from 3 to 12, as shown in Table 5. The ratio of phage suspension to buffer solution was 1:10. After incubation for 1 hour, the remaining titer was determined. The initial titer was 1.0 × 10^6. 10 pfu / mL.

[0051] Table 5: Results of bacteriophage titer determination under various pH conditions

[0052] 5.2 Experimental Results and Analysis like Figure 4 As shown in Table 5, this bacteriophage retains over 90% of its activity within a pH range of 4-11; and maintains approximately 50% activity at pH 3 and pH 12. This indicates that it has extremely strong acid and alkali tolerance, enabling it to adapt to the acidic environment (pH 4.5-5.5) on vegetable surfaces and the complex pH environment of the poultry gastrointestinal tract.

[0053] Example 6: Temperature stability of Salmonella phage from St. Paul 6.1 Experimental Methods The phage suspensions were treated in water baths at 40°C, 50°C, 60°C, and 70°C for 1 hour, and the remaining titers were determined.

[0054] Table 6: Results of bacteriophage titer determination under various temperature conditions (values ​​in the table represent lg (titer / pfu / mL))

[0055] 6.2 Experimental Results and Analysis like Figure 5 As shown in Table 6, this bacteriophage is extremely stable at 40°C-60°C; after treatment at 60°C and 70°C for 1 hour, its titer decreases by less than 1 log unit. This indicates that it has good thermal stability, making it suitable for room temperature transportation and storage.

[0056] Example 7: Whole genome analysis and safety evaluation of Salmonella São Paulo bacteriophage 7.1 Genome Sequencing After enriching the phages through culture, they were centrifuged at 8000g for 15 minutes at 4°C. Then, 10% PEG8000 and 0.5M NaCl were added and the mixture was allowed to stand overnight. An equal volume of chloroform was added and mixed thoroughly. After separation, the mixture was centrifuged at 5000g for 10 minutes. The chloroform and PEG layers were removed, and the phages were digested with restriction endonucleases. The phages were then resuspended under gradient density cesium chloride conditions. Finally, the phages were dialyzed three times with TM buffer, 30 minutes each time. A portion of the phages was sent to a biosequencing company for whole-genome sequencing. The sequencing method is as follows: The library was constructed using the Illumina TruSeq™ Nano DNA Sample Prep Kit method; the specific steps are as follows: 1) Construct a library starting with 1 μg of DNA; 2) Covaris M220 ultrasonically breaks down DNA to 300-500 bp; 3) Fill in the 3' end with an A and connect the index adapter (TruSeq™ Nano DNA Sample Prep Kit); 4) Library enrichment, PCR amplification for 8 cycles; 5) 2% agarose gel recovery target band (Certified Low Range Ultra Agarose); 6) TBS380 (Picogreen) quantitative analysis: mix according to data ratio and run on the machine; 7) Bridged PCR amplification was performed on the cBot solid-phase vector to generate clusters; 8) Illumina Hiseq sequencing platform, performing 2×150bp sequencing.

[0057] The full-length genome of this bacteriophage is 43056 bp, and it does not contain virulence genes or lysogen genes.

[0058] 7.2 Security Analysis Genome annotation indicates that it is a double-stranded DNA bacteriophage with a genome size of approximately 43 kb. Key safety findings: Comparison with the Virulence Factor Database (VFDB) and the Antibiotic Resistance Gene Database (CARD) revealed no known bacterial virulence genes, antibiotic resistance genes, or lysogenic integrase genes in the genome. This indicates that it is a strictly lytic bacteriophage with high biosafety for use in food and aquaculture.

[0059] Example 8: Application of Salmonella S. Paulo bacteriophage 8.1 Application in controlling Salmonella São Paulo on tomato surface 8.1.1 Experimental Methods Fresh tomatoes were aseptically sprayed with Salmonella São Paulo inoculation (approximately 10^ 6 (CFU / tomato), divided into three groups of 20 each, and processed as follows: (1) Control group: Sprayed with PBS buffer; (2) Experimental group: Spraying bacteriophage suspension (10^ 8 PFU / mL); (3) Antibiotic control group: 10 mL of ciprofloxacin solution with a concentration of MIC of 1.0 μg / mL was sprayed. After treatment, tomatoes were stored at 25°C and samples were taken at 0, 24, 48 and 72 hours to detect the number of viable Salmonella on the surface.

[0060] 8.1.2 Experimental Results and Analysis like Figure 6 As shown, 48 hours after spraying with bacteriophage, the Salmonella S. Pauli bacterium load on the tomato surface decreased by 99.8% (3 log units), significantly better than the antibiotic control group (approximately 90% decrease). Even after 72 hours, the bacteriophage-treated group effectively inhibited bacterial regeneration, while the control group showed significant bacterial proliferation. This indicates that it can be effectively used for post-harvest preservation of vegetables, extending transportation and shelf life.

[0061] 8.2 Application in the prevention and control of Salmonella infection in broiler chicken models 8.2.1 Experimental Methods Sixty healthy 1-day-old broiler chickens were randomly divided into 3 groups: (1) Infection control group: Oral administration of Salmonella enteritidis (10) ^8 CFU / each, no treatment; (2) Phage treatment group: After infection, (10^ 6 PFU / mL); (3) Antibiotic treatment group: Ciprofloxacin was added to the feed after infection, at a dosage of 0.02% in drinking water, for 2 consecutive days; (4) The experimental period was 7 days. The mortality rate was observed daily. At the end of the experiment, an autopsy was performed, and the contents of the cecum were taken for bacterial colonization testing. Liver tissue was also taken for pathological examination.

[0062] 8.2.2 Experimental Results and Analysis Table 7: Pathological Examination Results

[0063] As can be seen from Table 7: (1) Mortality rate: The mortality rate of the phage treatment group was 40% lower than that of the infection control group, and the effect was comparable to that of the antibiotic treatment group; (2) Intestinal colonization: The amount of Salmonella colonization in the cecum of the phage treatment group was reduced by 95% compared with that of the infected control group (P<0.01). (3) Pathology: No obvious pathological damage was observed in the liver tissue of chickens in the phage treatment group, while obvious inflammatory cell infiltration and necrotic foci were observed in the infected control group; (4) Safety: After the experiment, the supply of bacteriophage to drinking water was stopped. Chicken feces were tested 72 hours later and no phage was detected, indicating that it can be quickly cleared from the animal body and there is no risk of residue.

[0064] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A broad-spectrum lytic Salmonella phage of St. Paul. (Salmonella Saintpaul bacteriophage) Its characteristics are, The name is RDP-SA-21032, which was deposited at the China General Microbiological Culture Collection Center on September 21, 2022, with the accession number CGMCC No. 45281.

2. The broad-spectrum lytic Salmonella phage of St. Paul as described in claim 1, characterized in that: The St. Paul's Salmonella phage is capable of lysing at least three serotypes of Salmonella St. Paul's, Salmonella Enteritidis, Salmonella Typhimurium, Salmonella Indiana, Salmonella Kentucky, Salmonella Delphi, Salmonella Stanley, Salmonella Schovanorum, Salmonella Agona, Salmonella Nevtenberg, and Salmonella Subrae.

3. The broad-spectrum lytic Salmonella phage of São Paulo according to claim 2, characterized in that: The St. Paul's Salmonella phage is capable of lysing St. Paul's Salmonella, Salmonella enteritidis, Salmonella typhimurium, Salmonella Indiana, Salmonella Kentucky, Salmonella Delphi, Salmonella Stanley, Salmonella Schuvachenko, Salmonella Agona, Salmonella Nevtenberg, and Salmonella Subrae.

4. The broad-spectrum lytic Salmonella phage of St. Paul as described in claim 1, characterized in that: The activity of the Salmonella phage from St. Paul remained above 90% after treatment with a buffer solution of pH 4-11 for 1 hour; and remained above 50% after treatment with a buffer solution of pH 3 or pH 12 for 1 hour.

5. The broad-spectrum lytic Salmonella phage of São Paulo according to claim 1, characterized in that: The titer of the Salmonella phage from St. Paul was reduced by less than 1 log unit after treatment in a 60°C water bath for 1 hour.

6. The broad-spectrum lytic Salmonella phage of São Paulo according to claim 1, characterized in that: The highest titer of the *Salmonella staunchiseptica* phage, 1.3 × 10⁻⁶, was observed when the multiplicity of infection was 0.

1. 10 pfu / mL.

7. A composition, characterized in that: Includes an effective amount of the Salmonella St. Pauli bacteriophage as described in any one of claims 1-6, and a food- or pharmaceutically acceptable carrier.

8. The use of the Salmonella St. Pauli bacteriophage according to any one of claims 1-6 or the composition according to claim 7 in the preparation of products for food surface sterilization or food preservation.

9. The use of the Salmonella St. Pauli bacteriophage according to any one of claims 1-6 or the composition according to claim 7 in the preparation of products for the prevention or treatment of Salmonella infection in livestock and poultry.

10. A complete kit for the prevention and control of Salmonella in the livestock and poultry farming to food processing chain, characterized in that, include: A first formulation comprising the *Salmonella staunchiseptica* bacteriophage according to any one of claims 1-6 or the composition according to claim 7, for administration to livestock and poultry; and The second formulation comprises the Salmonella St. Pauli bacteriophage according to any one of claims 1-6 or the composition according to claim 7, for application to a food surface; The São Paulo Salmonella phage in the first and second formulations is the same strain.

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