Micro December 2018

For dairy matrices compared to the FDA BAM Chapter 4 reference method, an 11 g portion 1

was added to 99 mL of BPBD and blended for 2 min. Following homogenization, ten-fold serial 2

dilutions were prepared in BPBD to obtain 1–100 CFU per plate. For comparison to the ISO 3

4832:2006 and ISO 16649-2:2001 reference methods, a 10 g portion was added to 90 mL of PSS 4

and homogenized for 2 min. Following homogenization, ten-fold serial dilutions were prepared 5

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in PSS to obtain 1–100 CFU per plate.

For all other foods compared to the FDA BAM Chapter 4 reference method, a 50 g portion 7

was added to 450 mL of BPBD and blended for 2 min. Following homogenization, ten-fold serial 8

dilutions were prepared in BPBD to obtain 1–100 CFU per plate. For comparison to the ISO 9

4832:2006 and ISO 16649-2:2001 reference methods, a 10 g portion was added to 90 mL of PSS 10

and homogenized for 2 min. Following homogenization, ten-fold serial dilutions were prepared 11

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in PSS to obtain 1–100 CFU per plate.

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For stainless steel and sealed concrete (4” x 4” surface area) compared to the FDA BAM

Chapter 4 reference method, after sampling each sponge was added to 25 mL of BPBD and 14

homogenized for 1 min. Following homogenization, 10 mL aliquots were serially diluted in 90 15

mL of BPBD to obtain 1–100 CFU per plate. For test portions compared to the ISO 4832:2006 16

and ISO 16649-2:2001 reference methods, after sampling each sponge was added to 25 mL of 17

PSS and homogenized for 1 min. Following homogenization, 10 mL aliquots were serially diluted 18

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in of 90 mL PSS to obtain 1–100 CFU per plate.

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The 3M Petrifilm Rapid E. coli /Coliform Count Plates were placed on a flat, level surface. The

top film of the plate was lifted, and with the pipette perpendicular to the plate, a 1 mL aliquot 21

of each dilution was dispensed onto the center of the bottom film. The top film was rolled 22

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