Food Safety Hazards Associated with Fresh Produce

Food Safety Hazards Associated with Fresh Produce William C. Hurst, Ph.D. Food Science and Technology University of Georgia Athens, GA 30602 Sponsored by: USDA-CSREES CSREES Project Number 00-51110-9722 National Integrated Food Safety Initiative

Types of Hazards • Microbiological • Chemical • Physical Courtesy of W.C. Hurst

What is a “Pathogen” • Plant pathogen • Microorganism known to cause diseases or lesions in plant tissues • Human or animal pathogen • Microorganisms known to cause illness to animals or humans Courtesy of W.C. Hurst

E. coli O157:H7 Salmonella spp Listeria monocytogenes Shigella spp. Vibrio cholera B. cereus Hepatitis A virus Cyclospora Cryptosporidium Microbial Pathogens of Concern in Fresh Produce Viruses and Parasites Bacteria Courtesy of Cornell University

Normal inhabitants of soils L. monocytogenes B. cereus C. botulinum Residents of human and animal intestinal tracts Salmonella E. coli O157:H7 Shigella Campylobacter Viruses Ecological Niches of Microbial Pathogens Courtesy of Cornell University

Published Outbreaks of Bacterial Foodborne Illness Associated with Produce • Bacillus cereus – sprouts • Enterotoxigenic E. coli - carrots • E. coli 0157:H7 - unpasteurized apple cider/juice, lettuce, alfalfa sprouts, radishes Courtesy of W.C. Hurst

Published Outbreaks of Bacterial Foodborne Illness Associated with Produce • L. monocytogenes – cabbage • Salmonella – sliced tomatoes, sliced cantaloupe, sprouts, sliced watermelon, unpasteurized orange juice • Shigella – lettuce, green onions • Vibrio cholerae – coconut milk . Courtesy of W.C. Hurst

Published Outbreaks of Viral/Parasitic Foodborne Illness Associated with Produce • Hepatitis A – Iceberg lettuce, raspberries, strawberries • Cylcospora – raspberries • Crytosporidium – apple cider Courtesy of W.C. Hurst

MICROBIOLOGICAL TESTING Courtesy of W.C. Hurst

Microorganisms in Fresh Vegetables Courtesy of W.C. Hurst

Types of Microbiological Testing on Produce • Total plate count (TPC or APC) • Determine population of viable microorganisms present • Yeast-mold count (YM) • Determine number of mold fragments and yeast cells present • Lactic acid bacteria count • Determine population of acid tolerant bacteria present • Presence of a specific pathogen • e.g. Salmonella, E. coli 0157:H7 Courtesy of W.C. Hurst

Purpose of Microbiological Testing • Compliance • Confirm that regulatory or contractual specifications are being met • Quality control/assurance • Verify Hazard Analysis Critical Control (HAACP) system • Troubleshooting • Determine source of spoilage or safety problems • Courtesy of W.C. Hurst

MICROBIOLOGICAL SURVEY EQUIPMENT Courtesy of W.C. Hurst

COLIFORM GROWTH Courtesy of W.C. Hurst

CLEANING AND SANITIZING THE PACKING LINE Courtesy of W.C. Hurst

VERIFYING SANITATION Courtesy of W.C. Hurst

Water Testing • Research is needed relating to field irrigation water quality and risks • Fecal coliform count less than 100 per ml is target • Fecal coliform as indicator only partially useful, but best test available • Remember that very low bacterial counts of E. coli O157:H7 will cause disease • 6 to 10 bacterial cells can cause illness • Very difficult to test for this organism Courtesy of Cornell University

SIMPLE WATER TEST KIT Courtesy of W.C. Hurst

PORTABLE INCUBATOR Courtesy of W.C. Hurst

COLONY COUNTING MODEL Courtesy of W.C. Hurst

Water Testing Frequency • Annually with municipal water • Quarterly with groundwater • Test surface water for quality assurance • 3 times during season in temperate climates • at planting (high flow) • at peak use (low flow) • at harvest • Quarterly in more southern climates • Maintain good records of results Courtesy of Cornell University

HACCP • Hazard Analysis Critical Control Point System • Basic concept is that of “prevention” rather than “testing” • Only deals with Food safety issues • Procedures deal with continuous control of identified risks in the Food handling chain Courtesy of W.C. Hurst

7 Principles of HACCP • Conduct a Hazard Analysis • Determine Critical Control Points (CCP’s) • Establish Critical Limits • Establish Monitoring Procedures • Establish Corrective Action • Establish Verification Procedures • Establish Record Keeping and Documentation Procedures Courtesy of W.C. Hurst

Limitations of HACCP in Fresh Produce Production • True controls don’t exist for hazards • There is no definitive “kill” step • Industry doesn’t have trained personnel to run the program Courtesy of W.C. Hurst

What are the Alternatives? • Institute a HACCP-like program: • Hazard identification • Preventative steps • Documentation Courtesy of W.C. Hurst

WASH WATER QUALITY Courtesy of W.C. Hurst

CHLORINE TEST PAPER Courtesy of W.C. Hurst

ON-FARM HAZARDPREVENTION PLAN • Hazard identified: Human Pathogens • Preventative measure: Water Chlorination • Documentation step: Chlorine log Courtesy of W.C. Hurst

Food Safety Hazards Associated with Fresh Produce

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