AOAC 2019 First Action Methods

AOAC Official Method 2019.02 Enumeration of Total Aerobic Count in Select Foods MC-Media Pad ® Rapid Aerobic Count First Action 2019

(Applicable to the enumeration of total aerobic count in raw chicken breast, raw ground pork, cream cheese, yogurt drink, parsley, vegetable juice, prawns, tuna pâté, sandwiches and pasta salad.) See Tables 2019.02A and 2019.02B for a summary of results of the collaborative study. A. Principle The MC-Media Pad ® RAC is intended to enumerate viable total aerobic bacteria in select foods in as little as 24 hours. The MC-Media Pad ® RAC uses a special medium composition that reconstitutes automatically and a unique redox indicator for detection. Once the liquid sample is inoculated onto the test pad, the sample diffuses through the whole pad by capillary action. If target organisms are present, colonies appear red on the test pad. B. Apparatus and Reagents a. MC-Media Pad ® Rapid Aerobic Count – 100 test pads (25 pads/pouch, 4 pouches/ box). Available from MilliporeSigma #132302. b. Sterile Diluent- Butterfield’s Phosphate Buffer (BPB) c. Pipettes- capable of pipetting 1,000 µL or a serological pipette d. Sterile pipette tips- capable of 1,000 µL e. Laboratory paddle-blender- Seward 400 or equivalent f. Filter Stomacher bags - Seward or equivalent g. Incubators – Capable of maintaining 35 ± 1°C and 30 ± 1°C (ISO) h. Refrigerator - capable of maintaining 2-15°C, for storing the MC-Media Pads i. Standard Colony Counter or Illuminated Magnifier j. Top-loading balance – capable of weighing 1-2000 g C. General Instructions a. Read the instruction manual carefully before use b. Storage conditions: Store the MC-Media Pads at 2-15°C. After opening the aluminum bag, unused pads should be stored in the aluminum bag sealed with tape and kept in a cool (2-15°C) environment. After opening, use all pads within 1 month. c. Do not expose unused pads to sunlight or ultraviolet light. d. Do not use a discolored or damaged pad. e. A wrinkle on the test pad should not affect detection. f. Small fragments of fabric on or around the test pad should not affect detection. g. Do not use the pads after the expiration date. The quality of an expired product is not warranted. h. The measurement range is less than 300 CFU/pad. If more than 300 CFU/pad are counted, further dilution is recommended.