Antimicrobial effects of surface treatments and ingredients on cured RTE meat products

The objective of this study was to evaluate antimicrobial effects of surface treatments and ingredients on frankfurters. Thus, two frankfurter formulations were manufactured in a pilot plant to contain no potassium lactate (KL) (Control) or 3.3% KL. After cooking, chilling and peeling operations, each batch was divided into inoculated (L. monocytogenes) and non-inoculated groups. One hour post-inoculation, each group was treated 30 s with one of four different dips: Control (saline solution), acidified calcium sulfate with propionic acid (ACSP), 3.3% potassium lactate (KL) or 3.4% lactic acid (LA). Frankfurters were vacuum packaged, stored under refrigeration (4.5°C) and evaluated at two-week intervals (0, 2, 4, 6, 8, 10, 12). Physico-chemical, microbiological (APCs) and sensory evaluations were determined on non-inoculated samples. L. monocytogenes counts were determined on inoculated frankfurters. ACSP and LA dips were effective at reducing L. monocytogenes counts on the surface of frankfurters. Bactericidal and bacteriostatic effects for the ACSP dip were observed when L. monocytogenes counts were evaluated over storage. The most significant observations were that L. monocytogenes numbers were reduced by 5.8 logs on the surface of franks treated with ACSP dip and that after dip treatment L. monocytogenes counts remained at the minimum level of detection (1.7 log10 CFU/Frank) over the storage period. The addition of KL in the frank formulation did not affect fat, protein, ash, process yield, sodium, calcium, phosphorus, vacuum-package purge, pH, objective color or lactate values; except that aw and percent moisture were slightly lower. Proximate composition of frankfurters was not affected by dip treatments. Vacuum-package purge was slightly higher in samples treated with the ACSP dip and pH of the ACSP franks was 0.83 unit lower. Only slight changes in surface and internal color were noted for the ACSP dip. A slight increase in calcium content of franks dipped with ACSP was detected. Descriptive attribute sensory panel results indicated minimal effects on the sensory properties of the frankfurters containing KL and dipped in antimicrobial solutions. Application of ACSP to frankfurter surfaces was an effective bactericidal and bacteriostatic agent and could decrease the risk of L. monocytogenes contamination and thus enhance consumer safety.