Validating a Method to Ensure the Destruction of Salmonella on Product Surfaces During Impingement Cooking

Abstract

This study investigated the effectiveness of cooking processes that incorporated hydrated surface lethality (HSL) steps for ensuring the reduction of Salmonella on the surfaces of small-dimension meat and poultry products cooked using short-duration, high-temperature impingement oven processes. Whole-muscle chicken tenders (3% fat), beef patties (10% and 30% fat), pork patties (10% and 30% fat), and chicken patties (10% and 20% fat) were surface inoculated with a 5-strain mixture of Salmonella to yield 8 log colony-forming units/g, then cooked in a two-zone impingement oven using either dry heat or steam-humidified HSL processes. The HSL steps used steam injection to control the wet-bulb temperature at either 71.1°C or 82.2°C. Dry-heat cooking processes using a dry-bulb temperature of 204.4°C and no steam-injected HSL steps failed to consistently achieve a 6.5 log reduction of Salmonella on chicken tenders and the low-fat patty products (≤10% fat). In contrast, processes incorporating an HSL step using an 82.2°C wet-bulb temperature in one or both zones resulted in ≥6.5 log reductions of Salmonella for all products. Sufficient reductions were achieved regardless of whether this 82.2°C wet-bulb HSL step was incorporated before or after a dry-cook step. Processes that incorporated an HSL step using a 71.1°C wet-bulb temperature in both zones also resulted in reductions ≥6.5 log for all products. Processes using a 71.1°C wet-bulb HSL step in only one zone delivered ≥ 6.5 log reduction for all of the patty products. However, the one-zone 71.1°C HSL step achieved ≥6.5 log reduction in chicken tenders only if used in the first zone of the two-zone oven. When the 71.1°C HSL step was used in the second zone for chicken tenders after using dry heat in the first zone, the target reduction of 6.5 log was not achieved. This research successfully validated approaches to ensure ≥6.5 log reduction of Salmonella on product surfaces.

Keywords

• impingement cooking
• hydrated surface lethality
• Salmonella
• thermal inactivation
• Food Safety and Inspection Service Appendix A