AOAC 2018 Methods

Safety Precautions

After use, the diluents and MC-Media Pads may contain microorganisms that may be a potential

biohazard. When testing is complete, follow current industry standards for the disposal of contaminated

waste. Consult the Safety Data Sheet for additional information and local regulations for disposal. To

reduce the risks associated with fungal infection and workplace contamination: Perform MC-Media Pad

testing in a properly equipped laboratory under the control of a skilled microbiologist.

D. Sample Preparation

1. Solid Foods – Place a 25 – g test portion in a filtered laboratory blender bag and add 225 mL of 0.1%

peptone water. If necessary, adjust pH to neutral. Homogenize with a laboratory blender.

2. Liquids – Liquid samples can be applied directly. If necessary, adjust pH to neutral (pH 7.0 ± 0.2).

For all products, if necessary, make 10-fold serial dilutions with 0.1% Peptone water.

3. Open the aluminum bag and remove MC-Media Pad.

4. Lift the transparent cover film and pipette 1.0 mL of sample solution onto test pad. (It is

recommended to lift the cover film diagonally for easy and secure re-sealing).

5. Close the cover film and lightly press the edges of the film to seal.

6. Incubate the test pad at 25 ± 1 o C for 48-72 hours.

7. After incubation, count all reddish colored colonies. Yeasts will appear as circular reddish colored

colonies. Molds will appear as diffuse and fuzzy round reddish colored colonies.

8. If a large number of colonies are difficult to count, estimate by counting colonies in one grid square

and multiplying by 20. If more than 10 4 microbes are grown, the entire test pad may appear stained and

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