What is the technology for foodborne pathogenic microbial control of probiotics and their metabolites?

Background
Probiotics are a group of living microorganisms that have a beneficial effect on human health when accumulated in certain quantities.
There are many types of probiotics, among which Lactobacillus, including most of Lactobacillus, Streptococcus, Schizococcus, and Streptococcus, are recognized as a safe class of probiotics; another group of probiotics that has been studied more is a portion of the bacteria in the genus Bacillus, which is more advantageous than Lactobacillus in terms of its application; there are also some of the bacteria in the genus Brautobacillus; and some of the fungi that have symbiotic relationships with the intestine, such as Saccharomyces cerevisiae, are also are considered to have probiotic properties.
The presence of foodborne pathogenic microorganisms in food not only accelerates food spoilage but also poses food safety risks. Many probiotic bacteria and their metabolites isolated from fermentation broths have been found to inhibit foodborne pathogenic microorganisms, which has the potential to be applied in food safety and quality control, and because of their probiotic properties, they are more advantageous than other foodborne pathogenic microorganisms control technologies, and they have a promising future for development. Types of probiotics and their metabolites for inhibiting foodborne pathogenic microorganisms
Probiotics and the metabolites they produce are diverse, and it has been found that many probiotics and their metabolites have the ability to inhibit a wide range of foodborne pathogenic microorganisms, including bacteria, fungi, and viruses.
The inhibitory effect of probiotics on foodborne pathogenic microorganisms depends not only on their species, culture conditions, and the types of metabolites secreted, but also on the characteristics of the foodborne pathogenic microorganisms themselves (species, drug resistance, ability to form biofilms, and ability to produce virulence factors).
Table 1 lists some of the probiotics with inhibitory effects on foodborne pathogenic microorganisms and their sources.

Table 1 Probiotics and their metabolites that inhibit foodborne pathogenic microorganisms
Application of probiotics and their metabolites for the control of foodborne pathogenic microorganisms
Foodborne pathogenic microbial control based on probiotics and their metabolites is a technology that utilizes the foodborne microbial inhibitory properties of probiotics and their metabolites and applies them to food products to control food safety and quality.
This technology is applied to food quality control in the form of purified or semi-purified products (single metabolites), cell-free extracts (complexes of metabolites), and probiotics (live bacteria) isolated from probiotic fermentation broths.
The type of probiotics and their metabolites, the application mode, the application conditions, the type of food matrix, the type of food-borne pathogenic microorganisms will have different impacts on the effect of their technical application (food safety, shelf-life extension and food quality maintenance).
1, in the fruit and vegetable safety and quality control in the application of fruits and vegetables of high water and sugar content, easy to mechanical damage, in the food-borne pathogenic microbial contamination and the role of enzymes under the occurrence of quality deterioration, and at the same time, because of its consumption of raw food, there is a risk of food-borne diseases.
(1) Fresh fruit and vegetable probiotics and their metabolites can be applied to the preservation and storage of fruits and vegetables. It has been found that pediocin has a good quality control effect on fresh vegetables such as lettuce, lettuce, celery and spinach, and can effectively reduce the number of Listeria monocytogenes produced in fresh vegetables during storage.
(2) Probiotics and their metabolites can control foodborne pathogenic microorganisms in fresh-cut fruits to ensure the safety and taste of consumers.
It has been found that the use of Lactobacillus rhamnosus GG sprayed directly onto the surface of fresh-cut apples can reduce the number of colonies of Listeria monocytogenes and Salmonella monocytogenes to varying degrees during the storage period, and at the same time, the color, soluble solids, and hardness of fresh-cut apples during the storage period can be well maintained.
(3) Probiotics and their metabolites can also be applied to the quality control of non-fermented juice drinks. Some scholars found that Lactobacillus rhamnosus GG can control the growth of E. coli in sea buckthorn juice drink during low and room temperature storage and ensure the quality of juice, and its control effect is related to the suitable growth temperature of probiotics.
2、Application in meat safety and quality control Meat and meat products are rich in flavor, variety and nutrients, which account for a large proportion of people’s daily diet, and are the main source of obtaining nutrients such as proteins and fats. Meat is easily contaminated by pathogenic microorganisms such as Escherichia coli, Listeria monocytogenes, Salmonella, Vibrio parahaemolyticus, etc. Incomplete sterilization and toxins produced by the pathogenic bacteria during the consumption process can cause a great potential risk of food safety. And some consumers are influenced by the Japanese and Mediterranean diet, some red meat and aquatic products (salmon, tuna, oysters) will tend to use raw food.
(1) Fermented meat products Probiotics can be used as fermentation agents to ensure the quality of fermented meat. The use of Lactobacillus plantarum and Lactobacillus texans as fermenters for the production of salami can reduce the colony count of Clostridium difficile in sausage by about 2 lg CFU/g.
The bacteriostatic effect of probiotics is slightly lower than that of chemical preservatives, but the addition of probiotics can reduce the amount of nitrite added in the sausage production process, improve the quality of fermented meat, and satisfy the current consumer’s concept of green, healthy, minimally-processed, and additive-free food purchasing.
The addition of probiotics both as a fermenter, but also has the role of biological protection agent, has been applied to a variety of meat safety and quality control, including sausage, bacon and so on.
(2) In addition to being used as a fermentation agent, fresh meat can also be soaked in probiotic solution for a certain period of time to ensure freshness and safety, taking into account the initial number of viable probiotic bacteria as well as storage conditions and other factors.
Research findings: Lactobacillus casei CTC494 was utilized to control Listeria monocytogenes in vacuum-packed smoked salmon stored at low temperature to ensure the microbiological safety and quality of smoked salmon. It was found that the quality control effect of smoked salmon was highly related to the probiotic strains, and that Lactobacillus flexneri CTC1742 was relatively weak in controlling Listeria monocytogenes in smoked salmon compared to Lactobacillus casei CTC494.
Foodborne pathogenic microbial control technologies based on probiotics and their metabolites have great advantages for food safety and quality control applications, but their industrialization still faces many problems.
The first thing to consider is the food safety of probiotics and their metabolites, at present, only probiotics and their metabolites in the newly released List of Strains that can be Used in Food and List of Strains that can be Used in Infant and Young Children’s Foods (No. 4, 2022) can be used in food, and their species are still relatively small, and it has been found that some bacteriostatic substances have inhibitory effects on the normal probiotic flora of the body, and the relationship between them needs to be further investigated. The relationship between them also needs further study.
References: Li Jianrong,Tan Xiqian,Wang Dan,et al. Progress of foodborne pathogenic microorganism control technology based on probiotics and their metabolites[J]. Journal of Food Science and Technology,2022,40(3):1 -12.