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Title: RECOVERY RATE OF LISTERIA MONOCYTOGENES FROM COMMERCIALLY- PREPARED FRANKFURTERS DURING EXTENDED REFRIGERATED STORAGE.

Author
item Wallace, Frederick
item Luchansky, John
item Call, Jeffrey
item PORTO, ANNA - FEDERAL UNIV. OF S. CATAR
item COCOMA, GEORGE - PROF. RES.ORGANIZATION
item HUFFMAN, RANDALL - AMERICAN MEAT INSTITUTE

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2002
Publication Date: 1/14/2003
Citation: WALLACE, F.M., LUCHANSKY, J.B., CALL, J.E., PORTO, A.C., COCOMA, G.J., HUFFMAN, R. RECOVERY RATE OF LISTERIA MONOCYTOGENES FROM COMMERCIALLY- PREPARED FRANKFURTERS DURING EXTENDED REFRIGERATED STORAGE.. JOURNAL OF FOOD PROTECTION. 2003. v.66 p.584-591.

Interpretive Summary: Infections with the bacterial pathogen Listeria monocytogenes account for almost 1 in 3 deaths due to foodborne illness in the United States. A recent draft risk assessment conducted for the U. S. Food and Drug Administration (FDA) and the Food Safety and Inspection Service (FSIS) of the U. S. Dept. of Agriculture (USDA) concluded that the risk from eating non-reheated frankfurters was a significant risk factor for contracting listeriosis. Because of this, the Agricultural Research Service (ARS) has conducted research into the frequency with which this pathogen contaminates ready-to-eat products. To assess the prevalence of L. monocytogenes in packages of frankfurters, about 33,000 packages, one pound each, were obtained from 12 volunteer commercial manufacturers over a two-year period. The 12 producers, each of which contributed about 2700 packages of frankfurters from one production run, were comprised of 9 large and 3 small plants located in 10 states. From a statistical perspective, 9 producers did not have any packages/pounds which tested positive, whereas the pathogen was recovered at a rate of 1.4%, 2.3%, and 16% from product from the remaining three plants. The recovery rate did not change appreciably over time and there was no appreciable difference in recovery rate of the pathogen between storage at 4° or 10°C or due to seasonality of manufacture. Genetic analysis of multiple isolates of L. monocytogens from each plant testing positive revealed that it was possible to recover isolates with more than one profile from a given plant. However, a single profile was displayed by 90% of the isolates tested. These data establish the prevalence, types, and viability of L. monocytogenes associated with commercially-prepared frankfurters during extended refrigerated storage. These prevalence data will allow further refinements in modeling of risk and exposure estimates and will assist in the design of testing programs to further improve food safety.

Technical Abstract: To assess the prevalence of Listeria monocytogenes in vacuum-sealed packages of frankfurters, about 33,000 packages, one pound each, were obtained by a third-party contractor from 12 volunteer commercial manufacturers over a two-year period. The 12 producers, each of which contributed about 2700 packages from one production run, were comprised of 9 large and 3 small plants located in 8 USDA/FSIS districts in 10 states. Five days following manufacture, 500 packages were sampled at the USDA/ARS Eastern Regional Research Center (ERRC) in Wyndmoor, PA, using the USDA/ARS package rinse method (Luchansky et al., J. Food Protect. 65:567-570, 2002). At regular intervals during subsequent storage at 4° and 10°C an additional 200 packages were tested for the pathogen at each sampling point. From a statistical perspective, 9 producers did not have any packages/pounds which tested positive, whereas the pathogen was recovered at a rate of 1.4% (plant 367), 2.3% (plant 439), and 16% (plant 133) from product from the remaining three plants. In total, 532 of 32,800 (1.6%) packages/pounds tested positive for the pathogen. The recovery rate did not change appreciably over time and there was no appreciable difference in recovery rate of the pathogen between storage at 4° or 10°C or due to seasonality. Molecular subtyping of multiple isolates from each plant testing positive revealed that although isolates with a signature ribotype were recovered from each plant, it was also possible to recover isolates with more than one profile from a given plant. More specifically, profile "A" was displayed by about 90% of the 1102 isolates tested and all of these isolates were serotype 1/2a. These data establish the prevalence, types, and viability of L. monocytogenes associated with commercially-prepared frankfurters during extended refrigerated storage.