U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


Date of this Version


Document Type



Published in Journal of Rapid Methods and Automation in Microbiology 7 (1999) 155-161


A rapid and easy method of obtaining a viable culture count, the Track-Dilution method, was evaluated and compared to Spiral Plating to obtain viable culture counts from ground beef samples and beef carcass su$ace tissue samples inoculated with salmonellae or Escherichia coli OIS7:H7. Based on the statistical analysis of the dataset (n = 125 samples), the Track-Dilution method results were not diflerent (P > 0.1) than those obtainedfiom Spiral Plating. Linear correlation of the scatterplot of Spiral Plating and Track-Dilution indicated a high level of agreement between these two methocis (9 = 0.97). The Track-Dilution method was a valid method for estimating viable culture counts for meat animal-derived samples with bacterial counts of more than 100 cfu/mL.