IMPROVED PATHOGEN CONTROL FOR POULTRY PROCESSING: EXPERIMENTALLY-VALIDATED MATHEMATICAL MODELS FOR SCALDING, CHILLING, AND POST-CHILLING

Without fundamental understanding of the mechanisms dictating bacterial cross-contamination and survival, critical poultry processing steps will continue acting as persistent reservoirs of foodborne pathogens.Accordingly, there is an urgent need to develop novel strategies whichappropriate Salmonella/Campylobacter dynamics during the scalding, chilling and post-chill stages.Not meeting this need represents a serious problem because without clear scientific foundations informing pathogen control, the increased demand for poultry products translates into increased potential for foodborne disease outbreaks.Therefore, ourlong-term goalsare (i) develop optimal real-time sanitization strategies for Salmonella/Campylobacter, adjustable to processing specifications, (ii) develop data-modeling informed surveillance to improve processor compliance.Towards these goals,this proposal'smain objectiveis to constructexperimentally-validated modelsfor predicting pathogen dynamics during the scalding, chilling and post-chill stages in terms of processing specifications. The main objective will be realized via the following three aims:1. Quantify the fundamental mechanisms regulating pathogen transfer and inactivation during immersion scalding.Wehypothesize, based on preliminary lab-scale experimentsand our previous modeling work, that mathematical models for pathogen (Salmonella,Campylobacter) inactivation and transfer could be developed as functions of scald water temperature and sanitizer chemistry, which have strong predictive capacity at the commercial-scale.2. Elucidate the key mechanisms determining pathogen cross-contamination and survival during immersion and air chilling.Considering our previous modeling results, wehypothesizethat (i) mathematical forms for pathogen (e.g.,Salmonella) transfer and inactivation could be quantified from simulated processing experiments and chemical reactions/dynamical systems theory, which have predictive merit at the industrial scale; and (ii) fluid dynamics modeling guided by experiments linking air flow/ temperature/ relative humidity to bacteria shed, transport and attachment dynamics can be used to accurately map potential pathogen spread during air chilling.3. Identify the major determinants of pathogen spread and survival during the post-chill portioning/comminuted process.Based on pertinent literature and in collaboration with Mr. Glenn Mott (Advisory team), wehypothesizethat mathematically describing pathogen (Salmonella,Campylobacter) cross-contamination and survival during the cutting/ grinding processes, contact between parts prior to tray pack, as well as during the post-chill dips, will lead to models that can provide a benchmark against which the relative risk of different post-chill treatment strategies can be compared.