Validation of the USDA/ARS package rinse method for recovery of Listeria monocytogenes from naturally contaminated, commercially prepared frankfurters.
The utility of the U.S. Department of Agriculture/Agricultural Research Service (USDA/ARS) package rinse method for recovering Listeria monocytogenes from the surface of contaminated foods was validated in comparison to the standard USDA/Food Safety and Inspection Service (FSIS) product composite enrichment method and two other methods using frankfurters from a lot with a known package prevalence rate of approximately 16% for this pathogen. One hundred packages from this batch of naturally contaminated, commercially prepared frankfurters were examined as follows: (i) the package exudative fluid was removed and tested using the standard USDA/FSIS product composite enrichment method; (ii) approximately 5 to 7 portions of frankfurters were removed to obtain a 25-g composite of meat that was then processed using the standard USDA/FSIS product composite enrichment method: (iii) 50 ml of 0.1% peptone water was added to each package, and the USDA/ARS package rinse method was performed on the remaining contents; and (iv) after removing the rinse fluid, the solid contents remaining in each package were directly enriched using the USDA/FSIS product composite enrichment method. These four methods identified that 7, 6, 15, and 9 of the 100 packages tested positive for the pathogen, respectively. Although no single approach yielded a positive result for every package that tested positive for L. monocytogenes by any one of the four sampling strategies, the USDA/ARS package rinse method was appreciably (P < 0.05) better than either the package exudate enrichment method or the standard USDA/FSIS product composite enrichment method at recovering the bacterium. These findings validate the sensitivity and ease of use of the USDA/ARS package rinse method using naturally contaminated frankfurters and argue strongly for its adoption for routine screening of ready-to-eat products that are prone to surface contamination with undesirable microbes such as L. monocytogenes.
US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Microbial Food Safety Research Unit, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
F Morgan
FM
Wallace
Jeffrey E
JE
Call
John B
JB
Luchansky
D000818:Animals; D015169:Colony Count, Microbial / Q000379:methods; D003257:Consumer Product Safety; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D018857:Food Packaging; D008089:Listeria monocytogenes / Q000254:growth & development / Q000302:isolation & purification*; D008461:Meat Products / Q000382:microbiology*; D012680:Sensitivity and Specificity; D014481:United States; D016885:United States Department of Agriculture