The Application and promotion of Nisin in the catering Industry

As a natural, safe, and highly effective antimicrobial peptide produced by the fermentation of Streptococcus lactis, nisin exhibits significant application value in the catering industry—particularly in ingredient preservation, quality control during processing, and safety assurance—thanks to its specific inhibitory effect on Gram-positive bacteria (especially food-spoilage and pathogenic bacteria such as Staphylococcus aureus and Listeria monocytogenes), as well as advantages including non-toxicity, easy degradability, and no impact on food flavor. However, its promotion needs to be advanced gradually in line with industry demands and technical adaptability.

I. Core Application Scenarios in the Catering Industry

(1) Preservation and Color Retention of Fresh Ingredients and Semi-Finished Products

In the catering industry, the spoilage of fresh meats (e.g., beef, pork), poultry (e.g., chicken, duck), and aquatic products (e.g., fish, shrimp, shellfish) is mainly caused by Gram-positive bacteria (such as Clostridium botulinum and Listeria monocytogenes) and some slime-producing bacteria. Additionally, oxidative browning during storage directly affects ingredient appearance and consumer acceptance. Nisin achieves preservation through two approaches:

Surface treatment: It is formulated into an aqueous solution of a specific concentration (usually 50–200 IU/mL) or compounded with citric acid, ascorbic acid, etc., and applied to ingredients via spraying, soaking, or coating to form a protective film that inhibits the growth of surface microorganisms.

Addition to semi-finished products: During the processing of semi-finished products (e.g., marinated meat, prefabricated fish fillets), nisin is added in accordance with food additive standards (China’s GB 2760 stipulates a maximum usage level of 0.5 g/kg in prefabricated meat products) to extend the shelf life under refrigerated conditions (0–4°C).

For example, in the preservation of fresh-cut beef, compounding nisin with natural plant extracts (e.g., tea polyphenols) can extend the refrigerated shelf life from 3–5 days to 7–10 days, while reducing browning caused by myoglobin oxidation and maintaining the fresh color of the ingredient. Furthermore, for dairy ingredients (e.g., fresh cream, cheese raw materials), nisin effectively inhibits spoilage caused by Lactococcus and Bacillus, preventing premature deterioration of ingredients.

(2) Quality Improvement and Safety Assurance of Heat-Processed Catering Products

Heat processing is a common procedure in the catering industry, but spores of some heat-resistant Gram-positive bacteria (e.g., Bacillus cereus) may survive conventional heating (e.g., 80–90°C for 10–15 minutes), revive and multiply after cooling, and pose a risk of food poisoning (e.g., vomiting, diarrhea). Nisin exerts a unique "inhibition-destruction" effect on spores:

On one hand, it penetrates the cortex structure of spores, disrupts their osmotic balance, and prevents spore germination.

On the other hand, for germinated vegetative cells, it binds to lipid Ⅱ (a key precursor for bacterial cell wall synthesis) on the cell membrane, forming transmembrane channels that cause leakage of cellular contents and subsequent cell death.

Based on this mechanism, adding nisin to heat-processed products (e.g., cooked braised meat, steamed staple foods, baked pastries) enables the combined strategy of "low-temperature short-time heating + Nisin synergistic bacteriostasis". This not only reduces heating intensity to preserve the texture and nutrition of ingredients (e.g., reducing moisture loss and excessive protein denaturation in meat caused by high temperatures) but also effectively controls heat-resistant bacterial contamination. For instance, adding 0.2 g/kg of nisin during the processing of Chinese-style braised duck allows the sterilization temperature to be lowered from the traditional 100°C to 90°C, while extending the shelf life of the product at room temperature (25°C) from 2 days to 5 days—without affecting the savory flavor or tender texture of the braised duck.

(3) Safety Protection of Ready-to-Eat Catering and Cold-Chain Meals

Ready-to-eat catering (e.g., salads, sandwiches, cold dishes) and cold-chain meals (e.g., prefabricated boxed meals, frozen soups) do not require secondary heating and are typically stored at 0–10°C (temperature fluctuations are common in cold-chain weak links). These products are vulnerable to contamination by pathogenic bacteria such as Listeria monocytogenes and Staphylococcus aureus, making them high-risk categories for food safety. Nisin’s characteristics make it an ideal protective agent for such products:

Its antibacterial spectrum highly matches the main pathogenic bacteria in ready-to-eat meals, enabling targeted inhibition of risk microorganisms.

It maintains stable activity in low-temperature environments and is not affected by cold-chain temperature fluctuations.

Its addition does not alter the texture (e.g., the crispness of salads, the softness of sandwiches) or flavor (e.g., the sauce aroma of cold dishes) of ready-to-eat meals.

For example, in vegetable salad preparation, compounding nisin (100 IU/mL concentration) with salad dressing and coating it on the surface of ingredients such as lettuce and tomatoes can inhibit the growth of Listeria monocytogenes (common in salads), extending the safe shelf life of the salad from 2 days to 4 days under 4°C refrigeration. In cold-chain prefabricated boxed meals (e.g., Kung Pao chicken boxed meals), adding nisin at 0.3 g/kg prevents Staphylococcus aureus from producing toxins even if the temperature briefly rises to 15°C (within 6 hours) during cold-chain transportation, ensuring food safety.

II. Promotion Paths and Challenge Responses of nisin in the Catering Industry

(1) Market Education and Awareness Popularization Based on "Natural and Safe" Attributes

Currently, awareness of nisin in the catering industry remains insufficient. Some catering enterprises (especially small, medium, and micro-sized ones) lack understanding of its source, safety, and compliance, and tend to choose traditional chemical preservatives (e.g., potassium sorbate). Promotion efforts need to emphasize two core selling points: "natural origin" and "safety certification":

On one hand, through industry exhibitions (e.g., China Catering Supply Chain Expo) and enterprise training, clarify that nisin is a natural antimicrobial peptide produced by microbial fermentation, which can be degraded into amino acids by proteases in the human digestive tract (with no residues or toxicity). It has also obtained GRAS (Generally Recognized as Safe) certification from the U.S. FDA (Food and Drug Administration) and compliance approval under China’s GB 2760.

On the other hand, to address consumers’ concerns about "food additives", catering enterprises can be encouraged to label menus or product packaging with "Contains natural antibacterial ingredient nisin to ensure food safety", conveying the consumer value of "safe preservation" and gradually building market trust. For example, some chain catering brands (e.g., Western fast-food chains, high-end prefabricated meal brands) have taken the lead in highlighting nisin’s natural attributes in product promotion, which not only enhances consumers’ recognition of product safety but also provides case references for industry promotion.

(2) Development of Scenario-Specific Compound Technology and Cost Optimization

Single-component nisin has limitations in some scenarios, such as a narrow antibacterial spectrum (limited effect on Gram-negative bacteria) and high usage concentration (increasing costs), which restrict its large-scale application in the catering industry. Promotion should focus on the development of "scenario-specific compound technology":

Compound formulation with natural substances: Compounding nisin with natural plant extracts (e.g., tea polyphenols, rosemary extract) or organic acids (e.g., citric acid, lactic acid) leverages synergistic effects to broaden the antibacterial spectrum (covering some Gram-negative bacteria such as Escherichia coli) while reducing nisin usage by 30%–50%, thereby lowering raw material costs for catering enterprises.

Adaptable dosage form development: Develop dosage forms (e.g., liquid, powder, microcapsules) tailored to the processing characteristics of different catering categories. For example, heat-resistant microencapsulated nisin is developed for high-temperature baking of pastries to prevent inactivation during baking (150–200°C); water-soluble nisin formulations are developed for spray preservation of fresh-cut fruits to ensure uniform adhesion.

In addition, reducing nisin’s raw material price through large-scale production (e.g., optimizing the fermentation process of Streptococcus lactis) is key to increasing acceptance among small and medium-sized catering enterprises. Currently, the market price of food-grade nisin in China has dropped from several thousand yuan per kilogram in the early stage to several hundred yuan per kilogram, gradually highlighting its cost advantage.

(3) Improving the Adaptability of Industry Standards and Application Specifications

The catering industry covers diverse categories (including Chinese cuisine, Western fast food, and ready-to-eat foods), with significant differences in processing techniques and storage conditions across categories. Therefore, nisin application specifications need to be refined based on industry characteristics:

For different catering categories (e.g., prefabricated meat products, ready-to-eat fruits and vegetables, dairy products), specify nisin’s recommended usage level, addition timing (e.g., soaking before processing, mixing during processing, spraying after finished product preparation), and applicable scenarios to prevent poor antibacterial effects caused by improper use.

Strengthen cooperation with catering industry associations (e.g., China Cuisine Association) to formulate the Guidelines for the Application of nisin in the Catering Industry, clarifying the compliant application scope of nisin in different categories and helping enterprises avoid food safety risks. For example, for ready-to-eat cold dishes, the guidelines can specify a maximum nisin usage level of 0.3 g/kg and recommend adding it after the finished product has cooled (temperature below 25°C) to avoid activity loss due to high temperatures.

(4) Customized Services and Case Demonstrations Tailored to Catering Enterprises’ Needs

Catering enterprises of different sizes and categories have varying demands for nisin:

Large chain catering enterprises focus more on standardization and cost control.

Small and medium-sized catering enterprises prioritize operational convenience and effect stability.

High-end catering focuses on ensuring no impact on flavor.

Promotion should provide customized services:

For large prefabricated meal enterprises, offer integrated services such as "Nisin + production line sterilization solutions", which not only optimize nisin’s addition process but also combine workshop environmental disinfection to form a full-chain antibacterial system.

For small and medium-sized fast-food restaurants, provide pre-diluted liquid nisin to simplify operational procedures (only requiring proportional addition to ingredients) and lower the threshold for use.

Meanwhile, through typical case demonstrations (e.g., a chain salad brand reducing food safety complaints by 60% after using nisin, or a braised meat enterprise reducing loss rates by 30% after extending shelf life), the application value of nisin can be intuitively demonstrated, encouraging more catering enterprises to adopt it.