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.
Wallace
F Morgan
FM
US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Microbial Food Safety Research Unit, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
Call
Jeffrey E
JE
Luchansky
John B
JB
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