Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2005
Publication Date: 1/1/2007
Citation: Luchansky, J.B., Call, J.E., Cocoma, G. 2007. Hot water post-process pasteurization of cook-in-bag turkey breast treated with and without potassium lactate and sodium diacetate and acidified sodium chlorite for control of listeria monocytogenes. Journal of Food Protection. 69(1):39-46. Interpretive Summary: Listeria monocytogenes continues to be a significant threat to the safety of our food supply. Ready-to-eat (RTE) meat and poultry products, including deli meats, frankfurters, and cook-in-the-bag turkey breast (CIBTB), have been responsible for many large recalls and numerous illnesses in recent years. Ingestion of this bacterium is particularly worrisome for susceptible populations, because for young, old, pregnant, and immuno-compromised individuals the mortality rate is greater than 25 percent. The present study evaluated food grade chemicals, namely potassium lactate and sodium diacetate (organic acids) and acidified sodium chlorite (ASC), and hot water pasteurization to control L. monocytogenes on CIBTB. The results revealed that passage of commercial CIBTB spiked with L. monocytogenes through a pasteurization tunnel for 3 minutes while showered with water heated to 203°F killed about 99% of the pathogen cells in each vacuum-sealed package of CIBTB. Inclusion of organic acids as an ingredient, alone or in combination with ASC applied to the surface of CIBTB, limited the growth of the pathogen during the refrigerated shelf life of the product compared to otherwise similar CIBTB that did not contain these food grade chemicals. Our findings confirm that hot water post-process pasteurization provides an appreciable reduction in the levels of L. monocytogenes on the surface of CIBTB. However, further studies are needed to optimize the types, levels, and delivery of food grade chemicals to prevent outgrowth of this food borne pathogen during shelf life.
Technical Abstract: Surface pasteurization and food grade chemicals were evaluated for post process control of listeriae on cook-in-bag turkey breasts (CIBTB). Individual CIBTB were obtained directly from a commercial manufacturer and surface inoculated (20 ml) with a 5-strain cocktail (ca. 7.0 log10 total) of Listeria innocua. In each of two trials, the product was showered/submerged for up to 9 minutes with water heated to 190°, 197°, and 205°F in a commercial pasteurization tunnel. Surviving listeriae were recovered from CIBTB by rinsing and then enumerated on MOX agar plates following incubation at 37°C for 48 hours. As expected, higher water temperatures and longer residence times resulted in a greater reduction of L. innocua. About a 2.0-log10 reduction was achieved within 3 minutes at 205° and 197°F and within 7 minutes at 190°F. In related experiments, the following treatments were evaluated for control of Listeria monocytogenes on CIBTB: 1) Opti-Form® 4 (1.54% potassium lactate and 0.11% sodium diacetate) added to the formula in the mixer and 150 ppm acidified sodium chlorite (ASC) applied to the surface with a pipette, or 2) Opti-Form® 4 only, or 3) no Opti-Form® 4 and no ASC. Each CIBTB was inoculated (20 ml) with about 5 log10 CFU of a five-strain mixture of L. monocytogenes and then vacuum-sealed. In each of two trials, half of the CIBTB were exposed to 203°F water for 3 minutes in a pasteurization tunnel and then all CIBTB were stored at 4°C for up to 60 days and L. monocytogenes were enumerated by direct plating onto MOX agar. Heating resulted in an initial reduction of about 2 log10 CFU of L. monocytogenes per CIBTB. For heated CIBTB, L. monocytogenes increased by about 2 log10 CFU per CIBTB in 28 (treatment 1), 28 (treatment 2), and 14 (treatment 3) days. Thereafter, pathogen levels reached about 7 log10 CFU per CIBTB in 45, 45, and 21 days for treatments 1, 2, and 3, respectively. In contrast, for non-heated CIBTB, L. monocytogenes levels increased from about 5 log10 CFU per CIBTB to about 7 log10 CFU per CIBTB in 28, 21, and 14 days for treatments 1, 2, and 3, respectively. Lastly, in each of three trials we tested the effect of hot water (203°F for 3 minutes) post process pasteurization of inoculated CIBTB on lethality towards L. monocytogenes and validated that it resulted in a 1.8-log10 reduction in pathogen levels. Collectively, these data establish that hot water post-process pasteurization alone is effective in reducing L. monocytogenes on the surface of CIBTB. However, as used in this study, Opti-Form® 4 and ASC were only somewhat effective at controlling the subsequent outgrowth of this pathogen during refrigerated storage.