Cetylpyridinium Chloride Treatment of Ready-to-Eat Polish Sausages: Effects on Listeria monocytogenes Populations and Quality Attributes

Abstract

Ready-to-eat Polish sausages were inoculated with Listeria monocytogenes at either low (3 log₁₀ CFU/g) or high (7 log₁₀ CFU/g) levels, treated with a 1% cetylpyridinium chloride (CPC) spray (20 psi, 25°C, 30-sec exposure), vacuum packaged, and stored for 42 days at 0°C or 4°C. Non-inoculated samples were similarly treated, packaged, and stored to determine effects on color, firmness, and naturally occurring bacterial populations such as aerobic plate counts (APC). At the low inoculation level, L. monocytogenes populations were reduced by 1 log₁₀ CFU/g immediately after CPC treatment, and populations on treated samples remained approximately 2 log₁₀ CFU/g lower than non-treated samples throughout the 42-day storage period. At the high inoculation level, L. monocytogenes populations were reduced by 3 log₁₀ CFU/g immediately after treatment and, after 42 days of storage, populations on treated samples were 4 log₁₀ CFU/g lower than non-treated samples. Regardless of storage temperature, APC populations of CPC-treated samples were 1–2 log₁₀ CFU/g lower than non-treated samples throughout storage. An APC of 6 log₁₀ CFU/g was observed by day 7 of storage for non-treated samples, although not until day 21 of storage for CPC-treated samples. For samples stored at 4°C, no significant differences (p > 0.05) were observed for L*, a*, or b* color values of treated versus non-treated samples. At 0°C, the effects of CPC treatment on a* values were statistically significant (p ≤ 0.05), although minor. Non-treated samples were somewhat firmer than CPC-treated samples, primarily at the 0°C storage temperature, although the observed differences were of a magnitude unlikely to impact perceived product quality. CPC treatment appears to be a viable post-processing decontamination technology for eliminating and/or inhibiting L. monocytogenes on RTE meats during refrigerated storage without detrimentally impacting color and texture.