QUANTITATIVE MICROBIAL RISK ASSESSMENT OF FOODBORNE PATHOGENS OF HIGH PUBLIC HEALTH SIGNIFICANCE IN SPAIN: LISTERIA MONOCYTOGENES AND CAMPYLOBACTER JEJUNI IN PROCESSING CHAINS

THE PROJECT INTENDS TO ASSESS QUANTITATIVELY THE RISK FROM CONSUMPTION OF READY-TO-EAT FOODS CONTAMINATED BY L. MONOCYTOGENES AND CAMPYLOBACTER SPP. AT PROCESSING PLANTS FOLLOWING AN INTEGRATED VALUE CHAIN APPROACH. WITH THIS GENERAL OBJECTIVE, THE SUB-PROJECT 2 WILL INITIALLY PURSUE THE IDENTIFICATION AND CHARACTERIZATION OF HIGH-RISK SCENARIOS IN THE SEAFOOD AND MEAT SECTORS. FIRSTLY, AN EXPERT ELICITATION WILL BE CONDUCTED TO ELUCIDATE THE HIGHEST POTENTIAL TRANSMISSION PATHWAYS AND KNOWLEDGE GAPS IN PROCESSING CHAINS. ALSO, THE MOST RELEVANT FOOD WILL BE IDENTIFIED AND RANKED ON THE BASIS OF EXPOSURE TO PATHOGENS DURING PROCESSING, GROWTH DURING STORAGE, CONSUMERS’ PRACTICES AND IMPACT ON PUBLIC HEALTH. FOODS WILL BE PRIORITIZED FOLLOWING TOP-DOWN AND BOTTOM-UP APPROACHES FOR RISK RANKING. LASTLY, PROCESS VARIABLES INFLUENCING TRANSMISSION THROUGH THE SELECTED PROCESSING CHAINS, AND FOOD INDUSTRIAL OPERATIONS MODULATING SUCH VARIABLES WILL BE SELECTED FOR CELL TRANSFER AND MICROBIAL POPULATION DYNAMIC STUDIES. SECONDLY, THE RELEVANCE OF CROSS-CONTAMINATION OF FOODS WITH BIOFILM CELLS FOR RISK ASSESSMENT WILL BE ANALYZED. AT FIRST, BACTERIAL COMMUNITIES FORMING POLYMICROBIAL BIOFILMS IN HOT-SPOTS IN PROCESSING CHAINS OF HIGH-RISK FOODS WILL BE EXAMINED BY METAGENETIC ANALYSIS TO DETERMINE PREVAILING OPERATIVE TAXONOMIC UNITS. ALSO, BIOFILMS WILL BE SEARCHED FOR L. MONOCYTOGENES AND C. JEJUNI, WITH A PARTICULAR INTEREST IN PERSISTENT STRAINS. IN ADDITION, TARGETED SEAFOOD WILL BE SEARCHED FOR L. MONOCYTOGENES AT PROCESSING PLANTS AND RETAIL POINTS TO DETERMINE PREVALENCE AT DIFFERENT STAGES OF PRODUCTION. ISOLATES WILL BE TYPIFIED BY PFGE AND A REPOSITORY WILL BE ACHIEVED. NEXT, BIOFILM MODELS WILL BE DESIGNED BY COMBINING L. MONOCYTOGENES OR C. JEJUNI WITH PREVAILING ACCOMPANYING GENERA OR SPECIES. TO THIS END, STRAINS WILL BE SELECTED BASED ON THE RESPONSE TO PROCESS VARIABLES OF CONCERN, PERSISTENCE, EXPRESSION OF VIRULENCE DETERMINANTS AND INVOLVEMENT IN REPORTED OUTBREAKS. NEXT, THE EFFECTS OF ACCOMPANYING BACTERIA AND ENVIRONMENTAL FACTORS ON POPULATION DYNAMICS OF BIOFILM CELLS WILL BE EXAMINED UNDER CONDITIONS SIMULATING THOSE IN HOT-SPOTS, AND OUTCOMES WILL BE USED TO SELECT HIGHEST-RISK CASES. THE TRANSFER OF BIOFILM CELLS OF CASE STUDIES TO TARGETED FOODS WILL BE QUANTIFIED ON HIGH-RISK PATHWAYS OF PROCESSING CHAINS PREVIOUSLY IDENTIFIED. THE EFFECTS OF ACCOMPANYING BACTERIA, RELEVANT ENVIRONMENTAL FACTORS AND FOOD INDUSTRIAL OPERATIONS ON BIOFILM CELL TRANSFER WILL BE DETERMINED, AND OUTCOMES WILL POPULATE RISK ASSESSMENT. FINALLY, THE SAFETY OF TARGETED FOODS CROSS-CONTAMINATED BY BIOFILM CELLS WILL BE EVALUATED BY MONITORING POPULATION DYNAMICS OF L. MONOCYTOGENES AND C. JEJUNI. THIS WILL BE CONDUCTED AT THE PROCESSING STAGE, FROM TRANSFER SITES ALL ALONG THE PROCESSING CHAIN, WITH A PARTICULAR FOCUS ON CRITICAL CONTROL POINTS, AND ALSO AT RETAIL LEVEL, FROM FINAL PRODUCTION TO CONSUMPTION. THE LATTER WILL BE PERFORMED UNDER TEMPERATURE-TIME PROFILES CHARACTERISTIC OF DISTRIBUTION AND STORAGE, AND EXTENDED UNTIL FOODS BECOME UNACCEPTABLE FOR CONSUMPTION. LASTLY, MEASURES CURRENTLY IMPLEMENTED TO REDUCE THE INCIDENCE OF LISTERIOSIS AND CAMPYLOBACTERIOSIS WILL BE SURVEYED, AS WELL AS POTENTIAL FUTURE RISK MANAGEMENT MEASURES. THIS WILL BE CONDUCTED BY ALL SUBPROJECTS TOGETHER AND DIFFERENT REALISTIC RISK MANAGEMENT MEASURES WILL BE PROPOSED. MEASURES WITH MOST IMPACT ON RISK MITIGATION WILL BE FINALLY PRIORITIZED.