【 Principle 】

Soy peptone, meat peptone, and casein peptone provide the carbon source, ammonia source, and growth factors required for bacterial growth; Yeast extract powder provides B vitamins to promote bacterial growth; Sodium glycerophosphate maintains pH balance to neutralize the acids produced during fermentation; Ascorbic acid promotes the growth of Streptococcus thermophilus; Lactose as a fermentable carbon source; Magnesium sulfate provides the ions needed for growth; Agar is a coagulant.

Main components

Composed of soy peptone, meat peptone, casein, beef extract, yeast extract, lactose, sodium glycerophosphate, ascorbic acid, magnesium sulfate, agar, and distilled water.

Storage conditions and expiration date

Storage conditions: This product should be stored in a dark environment at 2-8 ℃.

Validity period: The unopened original packaging has a validity period of 3 months.

This product is a disposable product.

Counting of Streptococcus thermophilus in dairy products: quantitative detection of live bacteria in samples such as yogurt and fermented milk, commonly used in dairy quality inspection.

Fermented dairy product quality inspection: Yogurt and cheese are randomly inspected at the factory to determine whether the live bacteria content meets the standard.

Distinguish between two types of fermentation bacteria: β - glycerophosphate sodium inhibits lactobacilli, achieving separate counting of Streptococcus thermophilus and lactobacilli in yogurt.

Health food testing: Determination of viable bacteria count in probiotic preparations containing Streptococcus thermophilus.

Purification and strain maintenance: Select typical bacterial colonies for purification, use for strain identification, passage preservation, and fermentation experiments.

Streptococcus thermophilus

Biological characteristics: Staphylococcus aureus, arranged in pairs or short chains, without spores or flagella, facultative anaerobic; Growth is best at 42-43 ℃, slow at 37 ℃, and has better heat resistance than most lactobacilli; Efficient fermentation of lactose to produce lactic acid, without utilizing mannitol, using yogurt core fermentation strains; Fermented milk, cheese, probiotic preparations, food grade beneficial lactic acid bacteria; Strong adaptability to M17 matrix, with a faster proliferation rate than lactobacilli.

M17 Plate Culture Characteristics (42 ℃ microaerophilic, 24-48 hours): Medium sized colonies, milky white/milky white, round and plump, smooth and moist; No indicator, no red powder color change, transparent culture substrate color; Streptococcus thermophilus grows vigorously; Lactobacillus grows slowly and becomes small; Mixed bacteria (such as large intestine and mold) can grow in small amounts and need to be distinguished based on temperature and morphology.