Rapid detection of Staphylococcus aureus in dairy products

The growth of Staphylococcus aureus in dairy products is a potential danger because it can produce enterotoxins and cause food poisoning

[Detection principle]

Add a specific enzyme coloring agent to the selective medium and load it on a piece of paper.

[Instruments and reagents]

Constant temperature incubator, refrigerator, constant temperature water bath, electronic balance, homogenizer, oscillator, micropipette

Sterile normal saline: Weigh 8.

1mol/L sodium hydroxide : Weigh 40g sodium hydroxide and dissolve it in 1000mL distilled water

1mol/L hydrochloric acid: Pipette 90mL of concentrated hydrochloric acid and dilute to 1000mL with distilled water

[Operation method]

Sample pretreatment: Weigh 25g (mL) of sample under aseptic conditions and put it into a sterile conical flask or homogenization bag containing 225mL of physiological saline

Sample culture: Place the sampled test piece in a 37℃ incubator for 15~24h

[Result Judgment]

Observing the cultured test piece, the purple-red colony is Staphylococcus aureus

[Precautions]

For some dairy samples that have been roasted, heated or frozen, it is best to pre-enrich the bacteria with 7.

Note: The test piece after use should be treated in a harmless manner in accordance with the requirements of biosafety