​Bacterial colony count and initial contamination bacteria detection method of disposable medical masks

Bacterial colony count and initial contamination bacteria detection method of disposable medical masks

This method is applicable to the detection of the total number of colonies (hereinafter referred to as the total bacterial colonies) of the initial contaminated and fine seedlings of the product.

1.5.2.1 operation steps

After the normal saline sample solution settles naturally, the supernatant is taken for colony counting. A total of 5 plates were inoculated, and 1 ml sample solution was added to each plate, and then 15-20 ml of melted nutrient agar medium cooled to about 45 ℃ was poured into each plate and mixed evenly. After the agar was solidified, the plate was turned over and incubated at 35 ℃ for 48 h, and the number of colonies on the plate was calculated.

1.5.2.2 result report

It is not suitable to use the plate with plate-shaped colony growth: count the colony on the plate that meets the requirements, and calculate the result according to formula (4.5.1)

When the number of colonies is less than 100, it should be reported according to the actual number. When the number of colonies is greater than 100, two significant figures should be used.

If the total bacterial count of the sample exceeds the provisions of this standard, recheck and report the results according to 4.5.2.3.

1.5.2.3 re inspection method

If the average value of the results of the two times meets the requirements of this standard, the sample to be inspected is qualified; if the average value of any one of the results exceeds the provisions of this standard, the sample to be inspected is unqualified.