Microbiological principle: The production of yogurt needs to take milk as the basic raw material and ferment by adding lactic acid bacteria (such as Lactobacillus bulgaricus and Streptococcus thermophilus), so that lactose in milk can be converted into lactic acid under the action of lactic acid bacteria to form yogurt.

Food processing technology: the production of fruit and vegetable granules is usually to clean fresh fruits or vegetables, cut them into pieces, dry them, and make them into granules by crushing or granulator. In this process, heat treatment technology, such as hot air drying or microwave drying, can be used to kill microorganisms in fruits and vegetables and reduce moisture content, thus prolonging the shelf life of products.