Yogurt is a healthy food that consumers prefer. As the weather warms up, more and more people use yogurt machines to make their own yogurt at home. In general, home-made foods are less safe than formal enterprise products. For homemade yogurt, we should pay special attention to the following issues.
The more bacteria, the better？
The normal process for food companies to produce yogurt is like this. The raw milk collected from pastures is treated with simple filtration, homogenization and sterilization, and then it is put into fermentation lactic acid bacteria in a nearly aseptic state. After a period of fermentation, the yoghurt will be cooled and placed for a period of time to form a solidified yoghurt, but also after the completion of fermentation can add pulp and other ingredients. If after fermentation is finished heating again sterilizes, it is room temperature yoghurt. This process is sterile and cannot be done in the family.
The most important thing to make yogurt is the strain. Although there are a lot of bacteria that can ferment yoghurt, just look at the list of yogurt products on the market. The yoghurt starter sold online often contains a variety of bacteria, the most of which are more than ten. Is it that the more bacteria the better? The answer is no. This is simply a high-priced gimmick, and although some starter agents add a variety of “probiotics”, there is a competitive relationship between the different strains, and most of the probiotics die during the fermentation process. Secondly, the simultaneous fermentation of a variety of bacteria will not make yoghurt “more balanced nutrition”, the impact on the flavor of yogurt is very limited. The commonly used yogurt strains are Lactobacillus bulgaricus and Streptococcus thermophilus.
Container hygiene cannot be ignored.
Yogurt is a typical fermented food, because of the existence of dominant bacteria (lactic acid bacteria), other microorganisms are difficult to grow and reproduce, so the safety is quite high. But if the lactic acid bacteria in the initial stage of fermentation has not been firmly established in the case of mixed bacteria, it may lead to yogurt fermentation failure, and even produce food safety problems.
The raw material that makes yoghurt can choose pasteurized milk, normal temperature milk, all pass sterilize treatment, won’t have safe hidden danger generally. Even if the use of milk powder mixed raw materials, generally there will be no problem. One of the easiest things to mix in homemade yoghurt is a container. Self-made yoghurt is best to use a special container, each time the best use of high-temperature disinfection, so as to basically avoid yoghurt fermentation failure.
The quality of bacteria should be guaranteed.
Another common problem with home-made yogurt is the strain. Some consumers use leftover yogurt as a “drug guide,” a practice known in the laboratory as “inoculation” or “passage.” Because the family is not sterile, this process is susceptible to contamination by miscellaneous bacteria, and there are not a lot of live lactic acid bacteria in the remaining yoghurt, which brings opportunities for the reproduction of miscellaneous bacteria. In addition, lactic acid bacteria in the process of passage may also be mutated, resulting in flavor changes, and even reduced fermentation performance, which is the reason why some homemade yoghurt is too sour or even bitter.