Modeling the Survival of S almonella on Slice Cooked Ham as a Function of Apple Skin Polyphenols, Acetic Acid, Oregano Essential Oil and Carvacrol

Abstract

Response surface methodology was applied to investigate the combined effect of apple skin polyphenols (ASP), acetic acid (AA), oregano essential oil (O) and carvacrol (C) on the inactivation of Salmonella on sliced cooked ham. A full factorial experimental design was employed with control variables of ASP (0–10%), AA (0–4%), O (0–0.6%) and C (0–0.8%). AA, O and C were more effective in reducing Salmonella population densities on sliced cooked ham as compared with ASP; the reductions ranged from 1.2 and 4.4 log colony-forming unit (cfu)/cm2 for 1 and 4% AA, respectively, to virtually no reduction for 5 and 10% ASP. The interaction between ASP and AA, ASP and C, AA and C also had a significant influence on Salmonella reduction on sliced cooked ham. The highest reduction (6.9 log cfu/cm2) was achieved with the use of AA (4%) and C (0.8%) and the least effective was the use of a combination of ASP (10%) and O (0.6%) when the reduction was minimal, i.e., 1.7 log cfu/cm2. A second-order response surface model developed to predict Salmonella survival was found to be significant (P < 0.0001) with regression coefficients of 0.858 and an insignificant lack of fit (P = 0.4266). Results of this study will assist food processors and regulators in developing guidelines applicable to reducing Salmonella on ready-to-eat foods by combined use of ASP, AA, O and C. Practical Applications Predictive model developed will assist meat processors to estimate concentration of apple skin polyphenols, acetic acid, oregano and carvacrol to design processes to guard against Salmonella on RTE ham.