Food Safety Hazards Associated with Fresh Produce

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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

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Types of Hazards

• Microbiological
• Chemical
• Physical

Courtesy of W.C. Hurst
3
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

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Microbial Pathogens of Concern in Fresh Produce

Viruses and Parasites
Bacteria

• Hepatitis A virus
• Cyclospora
• Cryptosporidium

• E. coli O157H7
• Salmonella spp
• Listeria monocytogenes
• Shigella spp.
• Vibrio cholera
• B. cereus

Courtesy of Cornell University
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Ecological Niches of Microbial Pathogens

• Normal inhabitants of soils
• L. monocytogenes
• B. cereus
• C. botulinum

• Residents of human and animal intestinal tracts
• Salmonella
• E. coli O157H7
• Shigella
• Campylobacter
• Viruses

Courtesy of Cornell University
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Published Outbreaks of Bacterial Foodborne
Illness Associated with Produce

• Bacillus cereus sprouts
• Enterotoxigenic E. coli - carrots
• E. coli 0157H7 - unpasteurized apple
  cider/juice, lettuce, alfalfa sprouts, radishes
• Courtesy of W.C. Hurst

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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
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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

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MICROBIOLOGICAL TESTING
Courtesy of W.C. Hurst
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Microorganisms in Fresh Vegetables
Vegetable Population Recovered Reference
Bell Pepper 132,000 Golden et.al (1987)
Cabbage 500-100,000 Geeson (1979)
Carrot 440-630,000 Splittstoesser (1970)
Collards 3.2x106-6.3x106 Senter et.al (1987)
Cucumbers 16,000 Splittstoesser (1970)
Lettuce 10,000-1x106 Riser et.al (1984)
Lima Beans 1-150 Splittstoesser (1970)
Tomatoes 10,000-501,000 Senter et.al (1985)
Courtesy of W.C. Hurst
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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 0157H7
• Courtesy of W.C. Hurst

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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
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MICROBIOLOGICAL SURVEY EQUIPMENT
Courtesy of W.C. Hurst
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COLIFORM GROWTH
Courtesy of W.C. Hurst
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CLEANING AND SANITIZING THE PACKING LINE
Courtesy of W.C. Hurst
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VERIFYING SANITATION
Courtesy of W.C. Hurst
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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 O157H7 will cause disease
• 6 to 10 bacterial cells can cause illness
• Very difficult to test for this organism
• Courtesy of Cornell University

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SIMPLE WATER TEST KIT
Courtesy of W.C. Hurst
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PORTABLE INCUBATOR
Courtesy of W.C. Hurst
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COLONY COUNTING MODEL
Courtesy of W.C. Hurst
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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

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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
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7 Principles of HACCP

1. Conduct a Hazard Analysis
2. Determine Critical Control Points (CCPs)
3. Establish Critical Limits
4. Establish Monitoring Procedures
5. Establish Corrective Action
6. Establish Verification Procedures
7. Establish Record Keeping and Documentation
   Procedures

Courtesy of W.C. Hurst
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Limitations of HACCP in Fresh Produce Production

• True controls dont exist for hazards
• There is no definitive kill step
• Industry doesnt have trained personnel to run
  the program

Courtesy of W.C. Hurst
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What are the Alternatives?

• Institute a HACCP-like program
• Hazard identification
• Preventative steps
• Documentation

Courtesy of W.C. Hurst
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WASH WATER QUALITY
Courtesy of W.C. Hurst
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CHLORINE TEST PAPER
Courtesy of W.C. Hurst
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ON-FARM HAZARDPREVENTION PLAN

• Hazard identified Human Pathogens
• Preventative measure Water Chlorination
• Documentation step Chlorine log

Courtesy of W.C. Hurst