RI-ERP-FINALACTION-Recommendations

OMA 2015.13: Collaborative Study Protocol Expert Review Panel Use Only September, 2017

incubation Sample Preparation - 1:10 dilution of each test portion Skim milk and instant non-fat dried milk – 11mL/11g plus 99 mL of BPD

5.5.0.1.For skim milk, aseptically transfer 11 mL of skim milk to 99 mL BPD.Mix skim milk by shaking 25 times in 7 seconds through a one foot movement. 5.5.0.2.For instant non-fat dried milk, temper PBD to 40 ° to 45 °. Transfer 11g of instant non-fat dried milk to a sterile bottle or jar and add warmed diluent.Disperse sample completely before making any further dilutions 5.5.2.1.90 mL dilution blanks will be used to conduct the additional 3 dilutions for easy peel shrimp (10mL sample + 90mL BPD) 5.5.2.2.99 mL dilution blanks will be used to conduct the additional 3 dilutions for pasteurized skim milk and instant non-fat dried milk (10mL sample + 90mL BPD) 3M Petrifilm Rapid Aerobic Count Plate Method (please refer to the IFU for additional details) Place two (four if plating shrimp) 3M Petrifilm RAC Plates on a flat, level surface for each dilution to be tested. Lift the top film and with the pipette perpendicular dispense 1 mL of each dilution onto the center of bottom film of each plate. Roll the top film down onto the sample. Place the 3M Petrifilm Flat Spreader (6425) on the center of the plate. Press gently on the center of the spreader to distribute the sample evenly. Spread the inoculum over the entire 3M Petrifilm RAC Plate growth area before the gel is formed. Do not slide the spreader across the film. Remove the spreader and leave the plate undisturbed for at least one minute to permit the gel to form. Incubate 3M Petrifilm RAC Plates at 32°C (and at 35 °C for shrimp)in a horizontal position with the clear side up in stacks of no more than 40 for raw easy peel shrimp and no more than 20 for pasteurized skim milk and instant non-fat dried milk to ensure all plates reach the appropriate temperature. Enumerate plates after 24 ±2 hours for raw easy peel shrimp and skim milk and after 48 ±3 hours for instant non-fat dried milk. Count the 3M Petrifilm RAC Plates using a standard colony counter or other illuminated magnifier. Count all colonies regardless of color, size or intensity. The circular growth area is approximately 30 cm 2 . Gridlines are visible with the use of a backlight to assist with estimated enumeration. Estimates can be made on 3M Petrifilm RAC Plates containing greater than 300 colonies by counting the number of colonies in two or more representative AOAC Research Institute Expert Review Panel Use Only Raw easy peel shrimp - 50g plus 450 mL BPD (10 -1 ) and blend 2 minutes. Prepare an additional 3 dilutions (10 -2 to 10 -4 ) using BPD.