We evaluated the efficacy of potassium levulinate (KLEV; 0.0, 1.0, 1.5, and 2.0%) with and without a blend of potassium propionate (0.1%) and potassium diacetate (0.1%) (KPD) versus a blend of potassium lactate (1.8%) and sodium diacetate (0.125%) (KLD) for inhibiting Listeria monocytogenes on commercially prepared, uncured turkey breast during refrigerated storage. Product formulated with KLD or KLEV (1.5%) was also subsequently surface treated with 44 ppm of a solution of lauric arginate (LAE). Slices (ca. 1.25 cm thick and 100 g) of turkey breast formulated with or without antimicrobials were surface inoculated on both the top and bottom faces to a target level of ca. 3.5 log CFU per slice with a five-strain cocktail of L. monocytogenes, vacuum sealed, and then stored at 4°C for up to 90 days. Without inclusion of antimicrobials in the formulation, pathogen levels increased by ca. 5.2 log CFU per slice, whereas with the inclusion of 1.0 to 2.0% KLEV pathogen levels increased by only ca. 2.9 to 0.8 log CFU per slice after 90 days at 4°C. When 1.0% KLEV and KPD were included as ingredients, pathogen levels increased by ca. 0.8 log CFU per slice after storage at 4°C for 90 days, whereas a decrease of ca. 0.7 log CFU per slice was observed when 1.5 or 2.0% KLEV and KPD were included as ingredients. When used alone, KPD was not effective (≥5.8-log increase). As expected, KLD was effective at suppressing L. monocytogenes in uncured turkey breast. When uncured turkey breast was formulated with KLD or KLEV (1.5%) or without antimicrobials and subsequently surface treated with LAE, pathogen levels decreased by ca. 1.0 log CFU per package within 2 h; no differences (P ≥ 0.01) were observed in pathogen levels for product surface treated with or without LAE and stored for 90 days. Our results validate the use of KLEV to inhibit outgrowth of L. monocytogenes during refrigerated storage of uncured turkey breast. KLEV is at least as effective as KLD as an antilisterial agent.
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