New ideas for preserving yogurt

Currently, the development and applicationof natural food preservation solutions have become a hot spot for food scienceand technology research at home and abroad, and biological preservation isgaining more and more attention for its superior characteristics. Among them,the application of lactic acid bacteria preservative provides a new idea toextend the shelf life of fermented dairy products, using the natural microbialpreservative method of treating bacteria (yeast and mold) with bacteria (lacticacid bacteria), which can preserve freshness and enhance the food safety offermented dairy products. Recently, in an online lecture hosted by Cohansen,the industry discussed the value and mechanism of action of biopreservingbacteria.

　　Spoilage of fermented dairy productscaused by yeasts and molds is more taught common. According to industry insiders,mold fermentation can be a "fatal blow" to the food safety offermented dairy products and affect consumer confidence. Mold is the commonname for filamentous fungi, meaning "moldy fungi". Food contaminatedby mold, not only the color and flavor may change, nutrients will also bedamaged, reducing food value, some mold may also produce toxins in the food,endangering human health.

　　The risk of mold fermentationcontamination can be present in all stages of product production, marketing anddistribution, and the ingredients as well as the storage, distribution andretail conditions of the product (temperature, relative humidity, packaging)are all influential factors. On the farm, most fungi are heat sensitive and canbe inactivated by pasteurization, so raw milk and the farm environment are notcommon sources of mold and fermentation contamination of the final product. Inprocessing, contamination can come from high-risk processes and substandardproduction processes and ingredients. In packaging, contamination can come fromair (influenced by plant design, nearby plants, weather conditions, etc.) andpackaging materials. The risk of contamination at the distribution stage islow, but improper storage temperatures and times can increase the risk of spoilage.Ultimately, when the product reaches the consumer, there is also the potentialfor contamination, such as if the product is not consumed as soon as possibleafter opening, or if it is not stored properly.

　　Biofresh bacteria are selected from naturallactic acid bacteria to inhibit and retard the growth of mold and yeast infermented dairy products in a safe and natural way. The mechanism of its roleis mainly in three aspects: competition for nutrients; production of weakorganic acids, such as lactic acid and acetic acid; and production of naturalanti-bacterial metabolites.

　　According to Li Lun of Cohansen'stechnical department, manganese is naturally present in cow's milk and is anessential nutrient for the growth of many microorganisms. Screening lactic acidbacteria that efficiently utilize manganese, causing a manganese deprivedenvironment, can effectively inhibit the growth of molds and yeasts. Forexample, the fresh lactic acid bacteria products developed by Cohansen Bio canabsorb manganese ions through manganese transporter and play a bioprotectiverole. The test found that the yeast growth rate of yogurt added with preservedlactic acid bacteria was much lower than that of the blank control without theaddition when stored at 7 degrees Celsius for 25 days; and there was almost nogrowth of surface mold in yogurt added with preserved lactic acid bacteria whenstored at 7 degrees Celsius for 28 days. Meanwhile, through fermentationprocess monitoring and yogurt sensory evaluation, the additional addition ofpreserved lactic acid bacteria did not interfere with the normal fermentationprocess and had no negative impact on the texture, flavor and water holdingcapacity of the fermented dairy products.

　　According to Li Lun, the application ofbiofreshness preserving bacteria can extend the shelf life of fermented dairyproducts, improve the production efficiency, and thus reduce the loss fromproduction to the end.