Efficacy of Commercial Citrus-based and Chemical Preservatives against Survival of Campylobacter jejuni In Vitro and in a Food Model

Introduction: Campylobacter is associated with foodborne gastroenteritis in humans, and chicken plays a very important role for microbial dissemination. C. jejuni/coli have emerged over last decades as a significant pathogen of humans causing 400-500 million cases of campylobacteriosis each year worldwide. Methods to control contamination of these bacteria in foods are not completely successful. 

Purpose: To determine the efficacy of commercial, citrus-based and synthetic, preservatives and their mixtures, against survival of C. jejuni in vitro and in a food model.

Methods: Minimal Bactericidal Concentration (MBC) of Trisodium Phosphate (TSP), Citrosan and Citrol was determined against two strains of C. jejuni. The synergistic effect of preservative mixtures was determined using the checkerboard method. The most effective combination was evaluated in chicken wings using the Fisher method. Sensory analysis of this mixture was conducted by a semi-trained panel using the duo-trio method.

Results: The MBC against C. jejuni of TSP, Citrosan and Citrol were 0.5 ± 0.04%, 0.05 ± 0.0006% and 0.0006 ± 0.0001%, respectively. Combinations lower than individual MBC inhibited microbes, among them TSP:Citrosan at 0.4:0.03 %, TSP:Citrol at 0.3:0.0003% and Citrosan:Citrol 0.4:0.0005%. When mixtures were analyzed in chicken wings, the combinations 2:0.3:0.05% TSP:Citrosan:Citrol and 0.3:0.05% Citrosan:Citrol, both showed a reduction of at least 4 log of C. jejuni by 48 h. Sensory analysis showed no significant difference among the mixtures when compared with the chicken wings without preservatives.  

Significance: Mixtures of TSP, Citrosan and Citrol at concentrations lower than those suggested for individual use in the food industry, significantly reduced survival of C. jejuni in chicken wings.