Validation of a Chicken Surface Methodology to Assess the Performance of Antimicrobial Interventions on Chicken Parts

Introduction: The poultry industry in the United States. has to demonstrate control of Salmonella and Campylobacter prevalence in chicken parts and comminuted products as part of USDA performance standards. A series of antimicrobial interventions have been implemented at different stages of processing with mixed results. Unfortunately, the application in commercial settings does not allow processors to understand the effects of the intervention at the surface level.

Purpose: A validated methodology to simulate processing conditions and evaluate interventions under the conditions of processing stages is needed. A chicken surface coupon methodology was evaluated for this project using chicken skin and chicken meat surfaces to compare the efficacy of antimicrobial solutions on inoculated chicken pieces under simulated commercial conditions.

Methods: Fresh chicken skin and meat coupons (4 cm²) were inoculated with 20 µl of a five strains of Salmonella spp. cocktail and placed side up to allow attachment (20 min). Samples were subjected to antimicrobial applications, including lactic acid (LA; 5% v/v), cetylpyridinium chloride (CPC; 0.8% w/v) and peracetic acid (PPA; 400 ppm). The solution was sprayed on the top side of the chicken skin/meat for complete coverage. After treatment, each coupon was placed in a tube containing nine ml of nBPW and homogenized. Serial dilutions were made on BPW and dilutions were spread plated on XLD agar with TSA overlay. Plates were incubated for 24 h at 37°C. Plates were enumerated and bacterial populations were converted to log CFU/cm². Additional chicken skin/meat pieces were subjected to scanning electron microscopy to identify bacterial attachment and viability.

Results:  All interventions had an effect by reducing Salmonella attachment on chicken coupons. There was a statistical significant bacteria reduction (P<0.05) on the chicken meat coupons (0.85 log CFU/cm²) treated with LA, but nonstatistical significant on chicken skin.

Significance:  There is a need to screen the efficacy of antimicrobial interventions before selecting effective treatments for implementation. This methodology could facilitate this process for commercial operations.