Submitted to: Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/1/2009
Publication Date: 10/1/2009
Citation: Lloyd, T., Alvarado, C.Z., Brashears, M.M., Thompson, L.D., Mckee, S.R., Berrang, M.E. 2009. Control of Listeria monocytogenes in Turkey Deli Loaves using Organic Acids as Formulation Ingredients. Poultry Science. 88(10):2235-2239. Interpretive Summary: Listeria monocytogenes is a human foodborne pathogen which has caused outbreaks due to contaminated fully cooked meat and poultry products. Foodborne listeriosis is a serious disease with a high rate of mortality relative to other foodborne diseases. The meat and poultry industry is constantly looking for more effective means to control this pathogen in product. Food grade organic acids have bactericidal activity and are attractive for use as interventions in meat and poultry processing or as an additive in product. In this study, different combinations of organic acids (potassium lactate, sodium lactate and sodium diacetate) were tested as ingredients in the raw product formulation and as post-cook dip treatments for turkey deli loaves. Turkey deli loaves were formulated in a pilot processing plant, cooked, cooled then inoculated with a marker strain of Listeria monocytogenes. Deli loaves were stored under refrigeration for 56 d and cultured for L. monocytogenes at one week intervals. L. monocytogenes numbers increased during storage in untreated deli loaf product while the numbers did not increase in product treated with organic acids. This demonstrates that organic acid formulation and treatment may have utility for lengthening the lag phase and controlling the growth of this deadly pathogen in processed turkey meat products. Meat and poultry processors can use this information in planning product formulations and treatments to assure continued microbiological quality of the final product.
Technical Abstract: The growth of Listeria monocytogenes (LM) in further processed meat products has become a major concern and an important food safety issue. The meat and poultry industries have incorporated interventions such as organic acids in marinades in order to inhibit the growth of LM. In this study, organic acids were utilized in the raw product and as a post-cook dip to determine their inhibitory effect of the growth of LM in turkey deli loaves. The turkey deli loaves were processed, cooked, cooled, inoculated with Streptomycin-resistant LM, and then dipped. Treatments were potassium lactate (PL) in the raw product with sodium lactate (SL), sodium diacetate (SD) dip, PL with SL/PL/SD dip, SL with SL/SD dip, and SL with SL/PL/SD dip. There was also a positive (inoculated) and negative (non-inoculated) control, which was dipped in distilled water. Day 0, 7, 14, 21, 28, 42, and 56 were sampled for LM. There were no differences (P > 0.05) among the organic acid treatments in the turkey deli loaves at any time points; therefore, all the treatments increased the lag phase of LM, extending the shelf-life of the product. However, there was a difference between the treatments and the positive control at day 7, 14, 21, 28, 42, and 56. The growth of LM increased immediately in the positive control, while the negative control appeared to have no growth. These organic acids can provide meat processors with a useful method to extending the lag phase of LM in ready-to-eat meat and poultry products.