The rapid estimation of microbial contamination of raw meat by measurement of adenosine triphosphate (ATP)

Bacteria were separated from raw meat homogenate by a simple three-stage process. Centrifugation (10 s at 2000 g) removed coarse particles; stirring with the cation exchange resin Bio-Rex 70 removed smaller particles and filtration through 0.22 μm membranes removed soluble materials. By this process 70—80% of the microbial populations of meat homogenates were consistently isolated on the filters. A linear relationship was found between log₁₀ microbial ATP and log₁₀ colony count of meat over the range 10⁵—10⁹ cfu/g. The value of ATP/cfu for meat samples was within the range previously reported for pure cultures. These data indicated that ATP extracted from the filters originated from bacteria in the meat samples. Several samples can be analysed simultaneously in an elapsed time of 20—25 min. The variability associated with estimates of both colony counts and ATP levels has been determined.