Efficacy of organic acid-surfactants and sodium bisulfate in eliminating pathogens related to poultry and development of response surface model for prediction of survival of Campylobacter jejuni

Research reported in this dissertation represents an investigation into the effects of acidic treatments on the response of foodborne pathogenic bacteria that are associated with poultry products. The objectives of this research were: (1) Determine the ability of organic acid-surfactant treatments to eliminate Salmonella serotypes from poultry carcasses under pilot-processing conditions. (2) Utilize the skin attachment model (SAM) to determine the antimicrobial activity of sodium bisulfate against common foodborne pathogens attached to broiler skin. (3) Define the antimicrobial activity of common food-grade organic acids against Campylobacter jejuni. (4) Develop and evaluate a model to predict the survival of C. jejuni under various environmental conditions.; For objective 1, organic-surfactant treatments, either 0.5% wt./vol. acetic acid (AA) combined with 100 ppm sorbitan monolaurate (Span 20) or 0.5% wt./vol. lactic acid (LA) combined with 100 ppm Span 20, were applied by dip or spray after defeathering (post-pick) and/or during chill (post evisceration) under simulated commercial processing conditions. Both AA-Span 20 and LA-Span 20 were not effective in reducing Salmonella when applied at post-pick. However, application of either AA or LA combined with Span 20 during chilling was highly effective in eliminating Salmonella from broiler carcasses.; For objective 2, efficacy of sodium bisulfate against Salmonella serotypes, Listeria monocytogenes and C. jejuni attached to broiler skin was determined using the SAM. Aqueous solutions of sodium bisulfate with all application methods reduced populations of all three bacteria, as corhpared to populations recovered from skin treated with water only.; For objective 3, the effect of acidification (pH 4.56.5 in 0.5 unit increments) with different acidulants (acetic, citric, hydrochloric, lactic, malic, mandelic, propionic, or tartaric acid) on growth and survival of C. jejuni was determined in laboratory media. C. jejuni was capable of growth at moderately acidic environments; however, type of acidulant affected growth and survival.; For objective 4, primary and secondary models were used and evaluated for their ability to determine and predict the effects of temperature (4 and 10 C), pH (5, 6, and 7), and atmospheric conditions (aerobic and microaerophilic) on the survival of C. jejuni. Both modified Gompertz equation and Weibull distribution methods were able to predict the survival response to individual environmental treatments. (Abstract shortened by UMI.)...