A 25-g sample was placed into a Nasco Whirl-Pakâ stomacher bag along with 225 mL of sterile Butterfield’s diluent. Samples were agitated for 1 min in the Stomacherâ.18 Dilutions were prepared by transferring 11 mL of the sample homogenate into 99 mL of sterile
Butterfield’s diluent and agitating 25 times in a 29.58 cm arc in 7 s. Half-milliliter aliquots of the appropriate dilutions were transferred to duplicate sterile disposable Petri plates19 prepoured with hardened Plate Count Agar.20 Plates were inverted and incubated at 20 C for 5 d.
Counting and reporting microorganisms were conducted as described by