The fermentation characteristics of Lactobacillus helveticus, according to the standard of starter in fermented meat products, meet the requirements of fermented meat starter: (1) Lactobacillus helveticus is negative for amino acid decarboxylase activity, so it is safe. Microorganisms can produce large amounts of biogenic amines under the action of amino acid decarboxylase. Excessive biogenic amines can cause harm to the human body. (2) It is fermentable, can produce acid, does not produce gas, does not produce mucus, does not produce H2S, does not produce H2O2, and has the ability to reduce nitric acid. The H2S and H2O2 production test of Lactobacillus helveticus is negative, which ensures that the fermented meat will not produce H2S and H2O2 odors. In addition, H2O2 is a strong oxidant, which can oxidize heme compounds and polyunsaturated fatty acids, causing defects in the color and flavor of fermented meat products. However, the nitrate reductase activity of Lactobacillus helveticus was negative. Under the action of reducing bacteria, nitrate can be reduced to nitrite to produce color. Studies have found that although some strains such as Lactobacillus plantarum and Lactobacillus sake have nitrate-reducing ability, the effect is not ideal. Therefore, the nitrate-reducing ability of lactic acid bacteria is not required, and the addition of strong nitrate-reducing ability is often used. Micrococcus or Staphylococcus to make up for this defect of lactic acid bacteria. (3) It has good fermentation adaptability, salt tolerance and nitrate tolerance. (4) Reduce corruption and extend the shelf life of products. From the diameter of the inhibition zone, it can be seen that Lactobacillus helveticus has varying degrees of inhibition on pathogenic Staphylococcus aureus and Escherichia coli. The inhibitory effect of probiotics on pathogenic bacteria is one of the important indicators for their probiotic properties
