Title: Viability of Listeria monocytogenes on uncured turkey breast commercially-prepared with and without buffered vinegar during extended storage at 4 degrees and 10 degrees C Authors
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 12, 2014
Publication Date: N/A
Interpretive Summary: Food safety is still a major concern for consumers, and the manufacturing of natural ready-to-eat meats without antimicrobials may be a challenge for the meat industry, since these products may support the outgrowth of foodborne pathogens, especially Listeria monocytogenes. Therefore, research is warranted to evaluate the effectiveness of selected food grade antimicrobials to lessen the likelihood of pathogen persistence and human illness due to the consumption of ready-to-eat meat products. Thus, we evaluated the behavior of Listeria monocytogenes (about 10 thousand cells per slice) on the surface of on uncured turkey breast formulated with and without buffered vinegar and then surface treated with a solution of sodium chlorite in vinegar during storage at different temperatures. When product was formulated without antimicrobials, pathogen numbers increased to about 1 billion cells per slice after 90 and 48 days of storage at 4 or 10 degree Celsius, respectively. However, at 4 degree Celsius, when lower concentrations of buffered vinegar were added to the formulation, alone or in combination with surface treatment with sodium chlorite in vinegar, a slight growth of the pathogen was observed, whereas when buffered vinegar was used at high concentration, growth of the pathogen was inhibited throughout storage. As expected, the higher the storage temperature, the greater the pathogen levels on the surface of turkey breast. At 10 degree Celsius, lower concentrations of buffered vinegar and sodium chlorite in vinegar resulted in an increase greater or equal to 100 to 100,000 cells per slice, whereas at higher concentrations of both antimicrobials, pathogen numbers remained relatively unchanged. These data substantiate that inclusion of buffered vinegar, alone or in combination with VSC added to the package, appreciably suppressed the outgrowth of Listeria monocytogenes that may be present on the surface of natural deli turkey breast due to post-process contamination.
Technical Abstract: We determined the viability of Listeria monocytogenes on uncured turkey breast containing buffered vinegar (BV) and surface treated with a stabilized solution of sodium chlorite in vinegar (VSC). Commercially-produced, uncured, deli-style turkey breast was formulated with BV (0.0, 2.0, 2.5, or 3.0%), sliced (about 1.25 cm thick), and subsequently surface inoculated (about 4.3 log CFU per slice) with a five-strain cocktail of L. monocytogenes. Next, 1 ml of a 2 or 10% solution of VSC was added to each package before vacuum sealing and then storing at 4 or 10 degree Celsius. Without antimicrobials, L. monocytogenes increased by ca. 6.2 log CFU per slice after 90 and 48 days of storage at 4 or 10 degree Celsius, respectively. At 4 degree Celsius, L. monocytogenes increased by ca. 0.4 to 1.9 log CFU/slice on turkey breast formulated with 2.0 or 2.5% of BV and treated or not with 2% VSC, whereas when treated with 10% VSC, L. monocytogenes levels remained relatively unchanged over 90 days. However, when turkey breast was formulated with 3.0% BV and treated or not with VSC, pathogen numbers decreased by ca. 0.7 to 1.3 log CFU/slice. At 10 degree Celsius, L. monocytogenes increased by ca. 1.5 to 5.6 log CFU per slice after 48 days when formulated with 2.0 to 3.0% of BV and treated or not with 2% VSC. When formulated with 2.0% BV and treated with 10% VSC L. monocytogenes increased by ca. 3.3 log CFU per slice, whereas when formulated with 2.5 or 3.0% BV and treated with 10% VSC L. monocytogenes decreased by ca. 0.3 log CFU/slice. Inclusion of BV as an ingredient in uncured turkey breast, alone or in combination with VSC added to the package, appreciably suppressed outgrowth of L. monocytogenes during an extended refrigerated shelf life.