How can synergistic effects be utilized to enhance bacterial inhibition?

There are many kinds of preservatives, their bacterial inhibition mechanism and bacterial inhibition spectrum are different, a single food preservative usually can only target a particular spoilage bacteria to play a killing or inhibiting effect, and no inhibition of other bacteria or weak effect, but also easy to make microorganisms to produce adaptability. Based on the fence technology, different kinds of preservatives are used in combination, and their synergistic effect can not only enhance the bacterial inhibition effect, but also reduce the amount of single preservative used. This paper lists the research on the application of four kinds of compound preservatives in food production.
Research on the compounding of natamycin and lactic acid streptococcin[1]
The compounding of Natamycin and Streptocidin Lactate can inhibit the growth of fungi and bacteria at the same time, prolong the shelf-life of food, and has high research value in the food industry.
Natamycin, abbreviated as Natamycin, is a polyene macrolide antimicrobial agent mainly obtained by the fermentation of Streptomyces natalis and Streptomyces fusiformis and other streptomycetes; it usually exists in an enolic structure and is an odorless and tasteless crystalline powder. Nathamycin can effectively inhibit and kill yeast and mold, inhibit food spoilage and mycotoxin damage to human body.
Physical and chemical properties of Natamycin Natamycin is an amphoteric substance with one acidic group and one basic group in the molecule, which is almost insoluble in water and most organic solvents, and more soluble in dilute acid and alkali solutions such as glacial acetic acid and dimethyl sulfoxide. Due to the cyclic molecular structure, the stability of natamycin is affected by light, temperature, heavy metals, PH and other factors. The PH should be kept in the range of 4 to 7 while avoiding high temperature and light when using.
Inhibitory mechanism of natamycinNatamycin is a kind of specialized and highly efficient antifungal agent, which has a good inhibitory effect on almost all yeasts and molds. The inhibitory mechanism of natamycin is that it combines with ergosterol on the cell membrane to form a complex, thus changing the structure and permeability of the cell membrane, causing leakage of intracellular electrolytes, amino acids and other substances, and further causing cell death. Li Dong et al. showed that the minimum inhibitory concentration of natamycin on Aspergillus was 0.63 mg/kg, on Aspergillus niger was 1.80 mg/kg, and on Penicillium insulinum was 1.10 mg/kg. Zhang Xuan et al. showed that natamycin had a significant inhibitory ability on fungi, with a minimum inhibitory concentration of roughly 1mg/L. The study showed that natamycin had a significant inhibitory ability on fungi, with a minimum inhibitory concentration of roughly 1mg/L. The study also showed that natamycin has a significant inhibitory ability on fungi.
Streptococcus lactis, abbreviated as Nisin, is a peptide substance with bactericidal effect produced by Streptococcus lactis in the process of metabolism, which consists of 34 amino acid residues, and it is a kind of natural antiseptic with high efficiency and non-toxic side effects. Streptococcus lactis has a narrow antimicrobial spectrum and can only effectively inhibit food spoilage caused by bacteria.
Physicochemical properties of Streptococcus lactis Streptococcus lactis is very stable under acidic conditions, especially when the PH <2.0 can withstand 121 ℃ sterilization without inactivation; when the PH in the neutral and alkaline, after sterilization, Streptococcus lactis basic loss of vitality.PH and the solubility of Streptococcus lactis is also closely related to its solubility, with the decline of PH, its solubility increases.
It can act on the bacterial cell membrane to form a pore-like structure, breaking the balance between inside and outside the cell, leading to cell death; it can also inhibit the synthesis of peptidoglycan, so that the synthesis of the cell wall is blocked, thus inhibiting cell growth. Jiang Aili et al. showed that when the PH is in acidity, the concentration of Streptococcus lactis is higher than 10 μg/mL, which has a certain inhibitory effect on Listeria monocytogenes.
Composite preservatives in the food industry Yi et al. found that the composite preservative of Streptococcus lactis and natamycin had the best bacteriostatic ability on low-salt pickles. Streptococcus lactis and natamycin composite preservative had very little effect on the acidity and sensory of the pickles within 3 months, and the bacteriostatic effect was very good.
Gu Jiaying et al. found that adding 15 g/kg of streptococcus lactis and 100 mg/kg of natamycin compound solution to the egg yolk filling could achieve the purpose of internal preservation, and spraying the skin of egg yolk mooncake with 300 mg/kg of natamycin solution could achieve the purpose of external preservation.
Li Qingxiu et al. applied Streptococcus lactis and natamycin in chicken meat, which inhibited the growth of spoilage microorganisms in chicken meat and had no effect on the taste of chicken meat.
Ding Peifeng et al. experimentally studied the application of natamycin, lactic acid streptococcus lactis and tea polyphenol in soy sauce preservation, and found that a single preservative could not play a good bacterial inhibition effect, and the three kinds of preservatives in proportion to the compounding of the soy sauce shelf-life of up to 1 year.
Zhang Yuxin showed that when the ratio of Streptococcus lactis and natamycin was 0.02:0.0065, the bacteriostatic effect was comparable to that of potassium sorbate, which could effectively inhibit the growth of spoilage bacteria in the instant noodle packages.
Application of Streptococcus lactis and chemical preservatives in steamed cakes
At present, the chemical preservatives commonly used in cakes have a better inhibition effect on molds and yeasts, while the inhibition effect on bacteria is weaker. The biological preservative Streptococcus lactis is extracted from the fermentation product of Lactococcus lactis and has antibacterial activity of polypeptide substances, which can inhibit the growth and reproduction of many Gram-positive bacteria that cause food spoilage, especially on the heat-resistant bacillus, Clostridium botulinum and other spores produced by the bacterium with a strong inhibitory effect.
Zhang Panxian [2] et al. used Streptococcus lactis and commonly used chemical preservatives to inhibit spoilage microorganisms in steamed cakes and optimized compounding in their experiments, and the conclusions showed that the compounding preservative (0.2g/kg Streptococcus lactis + 0.25g/kg sodium dehydroacetate + 0.3g/kg sodium propionate) could significantly inhibit the growth of spoilage microorganisms in steamed cakes and the inhibitory effect was superior to the chemical preservative (sodium dehydroacetate), and the inhibitory effect of the chemical preservative (sodium dehydroacetate) could inhibit the growth of spoilage microorganisms in steamed cakes. It is better than chemical preservatives (sodium dehydroacetate and sodium propionate), which can improve the quality of the product and prolong the shelf life of the product. Compared with the chemical preservatives (sodium dehydroacetate and sodium propionate), the compound preservative with streptococcus lactis not only enhanced the inhibition of spoilage microorganisms in the steamed cake, but also reduced the amount of chemical preservatives added, and improved the safety of the product.
Application of compound preservatives in smoked sausages
Yao Yuan et al. found that a high concentration of sodium lactate can lead to the denaturation of actin and myosin heavy chain in pork; a low concentration of sodium lactate has no effect on the protein expression of pork. The antibacterial effect of sodium lactate-based compound preservatives is mainly through the effective penetration into the cell wall of bacteria and molds and interfere with enzyme interactions, inhibiting the production of bacteria and molds, so as to achieve the purpose of efficient antibacterial, antimicrobial, antiseptic and so on. Zhang Lifeng [3] and others in the test to low-temperature smoked sausage as the object of study, respectively, with a single and compound preservative preservative preservation test, the conclusion shows that before and after the treatment of smoked sausage in the volatile salt base nitrogen ( TVB-N ) and the total number of colonies of the changes in the measure of the inhibitory effect of the single and the compound preservative preservative preservative effect was found to be better than a single It was found that the antiseptic effect of compound antiseptic was better than that of single antiseptic.
It was found that the antiseptic effect of the compound preservative was better than that of the single preservative, and the test showed that the best antimicrobial effect was achieved by the compounded sodium lactate (2.0% sodium lactate + 0.04% sodium bisacetate solution + 0.006% streptococcal lactobionate). The compound product can obviously extend the shelf life of smoked sausage, and has the characteristics of good antiseptic effect, easy application, economy, safety and harmlessness, etc., which has a broad market prospect.
The effect of tea polyphenol composite bacteriostatic agent on the quality change of cold pork storage period
Due to consumers’ fear of chemical preservatives, scholars have focused on natural preservatives for cold meat preservation materials; natural preservatives are favored by scholars for their broad-spectrum, high efficiency and safety. So far, the commonly used natural preservatives in cold meat are: tea polyphenols, lactic acid streptococci, chitosan, natural spices, citric acid, lactic acid, lysozyme and so on.
In the early stage of natural preservatives research, many scholars have mostly studied the bacteriostatic spectrum of single natural preservatives and their effects on the dominant spoilage bacteria in meat and meat products. However, with the limited effect of a single bacteriostatic agent on the quality of meat products, people gradually change the research direction from single factor to multifactor synergistic effect, and the use of bacteriostatic agents also tends to be the composite use of a variety of bacteriostatic agents to achieve synergistic bacteriostatic effect.
Luo Jia [4] et al. used the cold meat of domestic pig slaughtering enterprises as raw materials, and used the natural preservative tea polyphenol, lactic acid streptococcus lactis and lactic acid sodium of the composite agent solution, to study the effect of different concentration combinations on the freshness of cold pork, the results show that in the single-factor test tea polyphenol, lactic acid sodium, lactic acid streptococcus lactis of the concentration of each solution can be significantly prolonged the shelf-life of the cold meat.
From the results of the orthogonal test, it can be seen that the effects of the three natural preservatives on the quality of cold meat were in the following order: tea polyphenol>sodium lactate>streptococcus lactis. And finally, the optimal ratio of the compound solution of tea polyphenol with sodium lactate and streptococcus lactis was determined as: tea polyphenol 0.02%, sodium lactate 0.25%, and streptococcus lactis 0.04%, which can prolong the shelf life of chilled meat to 9 days.
With the improvement of people’s material living standard, people’s demand for food is getting bigger and bigger, which makes part of the food need to be stored and transported for a long time before it can be consumed, so the preservation of food becomes an inevitable measure. Different types of preservatives can play a better role in inhibiting different kinds of microorganisms, so as a production enterprise needs to fully understand the characteristics of preservatives, and through the form of compounding to improve the effect of preservation.
References:
[1] Feng Linhui, Li Yingqiu. Application of natamycin and lactic acid streptococcinin compound in food. China Flavorings. Volume 44, Issue 2, February 2019 [2] Zhang Panxian, Ye Shengde, Zhou Bin. Research on the application of compound preservatives in steamed cakes. China Food Additives [3] Zhang LF, Ning HF, Liu YD, Zou S. Application of compound preservatives in smoked sausages Meat Industry. Issue 9, Total 437, 2017 [4] LUO Jia, ZHOU Yi, WANG Liting, CHENG Lijia, WANG Juan. Effect of tea polyphenol complex bacteriostatic agent on quality change of cold pork during storage period. Light Industry Science and Technology. Volume 37, Issue 3, 2021