【 Principle 】

Peptone and beef extract provide the nitrogen and carbon sources needed for bacterial growth; High concentration sodium chloride can inhibit the growth of non staphylococcal bacteria that are not tolerant to high salt; D-mannitol is a fermentable carbon source, and coagulase positive Staphylococcus can use D-mannitol to produce acid, causing phenol red to change from red to yellow; Agar is used as a coagulant.

Main components

Composed of tryptone, sodium chloride, D-mannitol, phenol red, beef extract, 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 6 months.

This product is a disposable product.

Count of Bacillus cereus in food: According to GB 4789.14, detect the wax content in dairy products, meat products and other foods to evaluate hygiene and safety.

Rapid identification of Staphylococcus aureus: Using high salt and mannitol fermentation, isolate and identify Staphylococcus aureus in clinical or food samples.

Distinguishing between Bacillus subtilis and miscellaneous bacteria: Distinguishing Bacillus cereus through yolk reaction and mannitol acid production, while inhibiting miscellaneous bacteria such as Escherichia coli.

Staphylococcus aureus

Biological characteristics: Staphylococcus aureus, facultative anaerobic, highly salt tolerant, can tolerate 7.5% NaCl; Fermentation of mannitol to produce acid; Secretes lecithin enzyme to break down phospholipids in yolk; Pathogenicity: Food poisoning caused by enterotoxin production, and pathogenic bacteria infecting the skin and wounds.

Colony characteristics: The colony size is moderate, with clear yellow borders (fermented mannitol produces acid, phenol red turns yellow), round, raised, and smooth; There is an opaque milky white precipitation ring around the periphery of the colony (characteristic of lecithin enzyme decomposition of yolk).

Bacillus cereus

Biological characteristics: Gram positive Bacteroides, with flat ends and a chain like arrangement of bacterial cells; Having flagella that can move; Formation of spores; Aerobic or facultative anaerobic, with an optimal growth temperature of 30-32 ℃. Colonies on regular agar are gray white, opaque, and have a rough surface resembling ground glass or melted wax

Colony characteristics: The colony is round, flat, with slightly expanded edges, with a diameter of 3-10mm, and is pink/micro pink in color (without fermenting mannitol, phenol red indicator does not turn yellow); There are white to pinkish white lecithin enzyme precipitation rings around the colony.