Comparison of media and a liquid detergent extraction step on bacterial recovery from animal feeds

The objective of this study was to evaluate the recovery of Tryptic soy agar (TSA) or low nutrient R2 bacterial populations from fresh feeds and animal feeds held in long-term cold storage after extraction with a detergent-based solution combined with repeated centrifugation. Repeated centrifugation after exposure to a detergent-based solution resulted in recoveries generally no more than 10% of the microbial population in the original feed. Feed R2A populations were significantly correlated (P<0.01) with TSA populations enumerated from the feed and feed extracts, as well as R2A populations from feed extracts. Similarly, TSA bacterial populations from feed were significantly correlated with TSA populations from extracts.