Prevalence And Antimicrobial Susceptibility Of Selected Food-borne Pathogens And The Critical Control Points Of Foodborne Pathogens At Yangzhou

Foodborne diseases have a major public health impact. The epidemiology offoodborne diseases is rapidly changing as newly recognized pathogens emerge andwell-recognized pathogens increase in prevalence. People give more and more attentionto the hazards that were caused by fooodborne pathogens. There were about 50% peopleinfected foodborne diseases in developed countries and the status in developingcountries was worse. The main reason causing death in developing countries werefoodbrone and waterborne diseases. The pathogens such as HIV, EHEC O157:H7,Vibrio cholera Serogroup O139, Listeria monocytogenes, C. jejuni and Y. enterocoliticaet al. have great influence to Chinese public health in 21st century, and most of thesepathogens could exist in foods. The prevalence and status of pathogens in foods is thebased data to study and prevent foodborne diseases. The increasing prevalence ofantimicrobial resistant bacteria is a major concern to human and veterinary medicine.The development of resistance in some human pathogens, such as methicillin-resistant S.aureus and multi-drug resistant Mycobacteria tuberculosis, is linked to the use ofantimicrobial drugs in human beings. In China, the studies about antimicrobial resistantof foodborne pathogens were much less compared with the clinical pathogens while the antimicrobial resistant of pathogen became a major focus in public safety. So weinvestigated the prevalence of antimicrobial resistance and the resistant phenotypesincluding Salmonella, L. monocytogenes and S. aureus in Chinese food products.The food poisoning reports caused by EHEC O157:H7 and Listeriamonocytogenes were rising although Salmonella, S. aureus, and V. phrahaemolyticuswere main the pathogens of foodborne diseases in China. In this study, we studyfollowing contents: 1) to learn the prevalence of Salmonella, S. aureus, V.phrahaemolyticus, EHEC O157:H7 and Listeria monocytogenes in ten kinds of foods,especially to study the prevalence of enterotoxin production of Staphylococcus aureusin the foods and find out the characters of V. phrahaemolyticus in aquatic productswhich was the first pathogen causing food poisoning in China. 2) to analysis theantimicrobial resistance of Salmonella, L. monocytogenes and S. aureus which was stillthe main factor of foodsafety. 3) to make hazard analysis (HA) and to find out thecritical control points(CCPs) of sporadic foodborne diseases. 4) to make hazardanalysis (HA) and to find out the critical control points(CCPs) of colony foodbornediseases.1. The status and prevalence of foodborne pathogens at YangzhouThe prevalence of foodborne pathogens was high in foods at Yangzhou from June2002 to May 2006. The prevalence of Salmonella, L. monocytogenes, S. aureus,, E. coliO157:H7 was 3.26%, 5.70%, 7.35%, 1.05%, 0.06% respectively. Enterotoxigenic S.aureus got to 56.32% in detected 98 isolates. The main hazards in foods wereSalmonella, L. monocytogenes, S. aureus, and V. phrahaemolyticus. V. phrahaemolyticusdetected in fresh water products was the main cause of foodborne diseases in summerand autumn at Yangzhou, also in China. Salmonella was isolated from samples of rawmeats and fresh milks. The main source of L. monocytogenes isolated in this study wascooked food products followed by raw meat products. S. aureus were isolated from raw meats, fresh milk and cooked foods in present study. The raw meats were the mainsource of foodborne pathogens. V. phrahaemolyticus in aquatic products especially infresh water products were the important factor of foodbonre diseases.2. The antimierobial resistance of Salmonella, L. monocytogenes and S.aureus isolated from food products at YangzhouAntimicrobial resistance in bacteria is an emerging and increasing threat to humanhealth. Bacteria resistant to anti-microbial drugs that penetrate into the humanpopulation with foods of animal origin and rank with direct causative agents offood-borne diseases represent a possible source of drug resistance for human pathogenicagents. Anti-microbial drugs not only affect the causative agent, but also affect othermicrobial species in the host organism and its environment. In China, more attentionwas paid to clinical antimicrobial resistance but less was given to the resistance causedby veterinary and environmental and other factors. Our study of antimicrobial resistanceshowed that Salmonella was sensitive to antimicrobial but more attention should focusto the strain of multi-drug resistance especially to 10 kinds of drugs, that most of Lmisolates occurred resistance to antimicrobial, there appeared 29 kinds of resistancephenotypes, even more, there were 31.58% strains showing resistance to 4 or morekinds of drugs with the most to 6 kinds, and that the resistance of S. aureus showed soserious that appeared higher resistance to penicillin and there were 16.33% strainsshowing resistance to 4 or more kinds of drugs with the most to 7 kinds. Theantimicrobial resistance of food-borne pathogens were mostly caused by the routine useof veterinary medicine to farm animals as growth promotants. In addition, the residuesof veterinary medicine could affect normal bacteria in intestines and promote the growthand replicate of the antibiotics resistance pathogens. Secondly, the factors in foodchains such as drug residues from animal carcase and excreta and from human beingcould affect the normal bacteria and further more induce the antimicrobial resistance of pathogens in intestines. Thirdly, antibiotics were used before pathogens isolating anddrug-resistance test. The other factors including misuse of antibiotics by healthprofessionals and unskilled practitioners, misuse of antibiotics by the public (antibioticscan be purchased without prescription), poor drug quality, unhygienic conditionsaccounting for the spread of resistant bacteria, and inadequate antimicrobial surveillanceprogram.3. Hazard analysis(H/A) and the critical control points(CCPs) ofsporadic foodborne diseasesBased on the biologic and epidemic characters of Lm in delicatessen foods, weapplied it as a symbol of normal foodborne pathogens in order to ascertain the criticalcontrol points (CCPs). So the critical control points (CCPs) of Lm are the CCPs offoodborne pathogens. Samples including delicatessen foods in markets and cookedfoods in restaurants and hotels, product contact surfaces such as counters and iceboxesand chopping blocks etc. from processing and selling sites and the cooked food roomsof restaurants and hotels were collected to isolate Lm. Statistic analysis showed thatthere was special significant difference between the two prevalence of foods indelicatessen and in restaurants and hotels(P＜0.01).There was significant differencebetween the two prevalence about appliances and environments of selling sites andhotels' and restaurants' cooked rooms (P＜0.05). The results showed that prevalence ofLm in delicatessen foods was higher than that in the cooked foods of hotels andrestaurants, which were affected by selling environments. The CCPs of sporadicfoodbome diseases based on the analysis above were: 1) to establish relative closedselling rooms. 2) the sterilizing measures to the iceboxes of reserving delicatessen foodsand to selling appliances. 3) the sterilizing measures to the conveyance. 4) the sterilizingmeasures to the processing. These points were not only for the delicatessen foods butfor the foods made in families in China. 4. Hazard analysis (HA) and the critical control points(CCPs) of colonyfoodborne diseasesTo make analysis to 70 cases of bacterial foodborne diseases in past 10 years atYangzhou City and make hazard analysis (HA) and find out the critical controlpoints(CCPs) of colony foodnorne disease. The isolated pathogens, the maincontaminative sources of pathogens, the main eontarninative foods and the key period of70 food poisoning cases were discussed and analyzed. The foodborne diseases causedby Pathogenic Vibrios covered 58.57%. The cases caused by germ carriers covered54.28%.The pathogens detected from the cold food rooms covered 91.30% of foodbornestrains. The cases occurred from July to September covered 65.72%. The hazard factorsof foodborne diseases at Yangzhou were Pathogenic Vibrios, Salmonellae andSaphylococcus aureus. The critical control points(CCPs) were: 1) food sanitationmanagement in cooked food rooms. 2) physical check-ups and sanitation trainings ofthe practitioners. 3)supply of meats, fish and vegetalbes in fresh. 4) to prevent thecross-contaminated and control the bacteria propagating in summer and autumn.