Food Safety


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Kansas Community Garden Conference
July 8, 2014
Mr. Marlin Bates

Ensuring that garden crops are safe to eat should be a priority for all gardeners. While no gardener would intentionally contaminate his/her own crop, some common practices could increase the chance of contamination. This session will discuss those practices and offer safer approaches to food production.

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Food Safety

  1. 1. Food Safety in the Garden Marlin A. Bates K-State Research and Extension Horticulture Agent – Douglas County
  2. 2. Agenda • Introduction • The Contaminants • Gardener Hygiene and Health • Water and Flooding • Soil, Manure, and Compost • Harvest/Post-Harvest
  3. 3. Introduction • Food Safety is everyone’s responsibility – Producer, Gardener, Cook, Consumer • Most food safety issues are biologically related – Physical contamination and heavy metal contamination are also issues
  4. 4. Donated Food • Bill Emerson Good Samaritan Food Donation Act – Protects donors from liability when they donate to a non- profit organization – Protects donors from civil and criminal liability should the product donated in good faith later cause harm – Donors are protected except in cases of gross negligence • Voluntary and conscious conduct by a person with knowledge (at the time of conduct) that the conduct is likely to be harmful to the health or well-being of another person.
  5. 5. The Contaminants
  6. 6. The Contaminants • E. Coli O157:H7 • Cyclospora (cyclosporiasis) • Hepatitis A • Listeria monocytogenes (listeriosis) • Norovirus • Salmonella (salmonellosis) • Shigella species (shigellosis)
  7. 7. Cyclospora (cyclosporiasis) • A protozoan • Caused by ingestion of food or water contaminated with infected stool • Symptoms- diarrhea, loss of appetite, weight loss, abdominal cramping, low-grade fever, nausea, vomiting, and fatigue
  8. 8. Hepatitis A virus • A virus • Symptoms include sudden onset of fever, malaise, nausea, anorexia, abdominal discomfort, followed by several days of jaundice • Virus is excreted in fecal material and transmitted via fecal/oral route • Commonly transmitted through contaminated shellfish and salads, and drinking water
  9. 9. Listeria monocytogenes (listeriosis) • A bacterium • Widespread in the environment • Has been isolated from raw produce, domestic animals, humans, food processing environments • Can cause serious disease in pregnant women, elderly and those with weakened immune systems • Outbreaks associated with consumption of hot dogs, deli meats, some soft cheeses, and raw vegetables
  10. 10. Norovirus • A virus (the “cruise ship” bug) • Causes non-fatal disease which includes gastrointestinal upset, headache, low grade fever, nausea, vomiting, and diarrhea • Commonly transmitted via fecal/oral route through contaminated water or food • Shellfish and salad ingredients are foods most often implicated in norovirus outbreaks
  11. 11. Salmonella (salmonellosis) • A bacterium • Symptoms of illness include nausea, vomiting, abdominal cramps, fever, mild diarrhea, and headache • Outbreaks associated with consumption of raw or undercooked eggs, undercooked poultry, dairy products made from unpasteurized milk, fresh produce, and unpasteurized fruit juices
  12. 12. Shigella species (shigellosis) • A bacterium • Primary means of transmission of shigella is fecal/oral route • Most cases of shigellosis attributed to ingestion of food or water contaminated with fecal matter • Humans are a natural reservoir for shigella • Poor personal hygiene of food workers often the cause of transmission • Symptoms include abdominal pain, cramps, diarrhea, fever, vomiting, and blood/mucus in stools • Outbreaks associated with shredded lettuce, green onions, parsley, etc
  13. 13. The Burden of Foodborne Illness • Foodborne diseases each year in US –Affects 1 in 4 Americans –76 million illnesses –325,000 hospitalizations –5,000 deaths
  14. 14. Produce-Related Outbreaks, 1990-2004 Source: Outbreak Alert!, CSPI, December 2006 Revision
  15. 15. Summary: Top Five Commodities Source: Food Protection Report, November 2006 (Volume 22, No. 11)
  16. 16. Contamination With Microbial Pathogens: Where Can It Occur? • In fields or orchards • During harvesting and transport • During processing or packing • In the home FARM to FORK
  17. 17. However, this “farm to table” control over all unit operations increases liability and hence, the necessity for doing things right.
  18. 18. Gardener Hygiene & Health
  19. 19. When To Wash Your Hands • After using toilet • After cleaning restroom • After smoking, eating or drinking • After changing diapers or linens • After handling garbage • After caring for or touching animals • After handling dirty equipment, utensils or farm machinery • Before you eat • Before you start to work • Before handling food • Between changing tasks or changing gloves • After engaging in other activities that soil hands
  20. 20. Do You REALLY Know How to Wash Your Hands? • 1. Wet hands with warm water • 2. Apply soap to hands • 3. Lather hands briskly for 20 sec. Areas of concentration: –Palm to palm –Palm on backs of hands –Claw paws in palms –Between fingers –Scrub forearm near wrists. –Left and right hands • 4. Rinse thoroughly • 5. Towel dry thoroughly with disposable paper towel Note: Lathering for less than 20 seconds is not good enough!
  21. 21. Using Hand Sanitizers • Is not a substitute for hand washing • Hands must be clean before sanitizer is used • “Experts” recommend using only alcohol-based sanitizers with emollients to prevent drying & chapping of skin • Use before bare-hand contact with ready-to-eat (RTE) foods Cabinet for Health
  22. 22. Use of Gloves • Hands must be washed before being gloved • Hands must be dry before putting on gloves • Use gloves for only one task • Caution on use of latex gloves… – They can cause allergies in both you and in consumers • Wash your hands after removing gloves Cabinet for Health
  23. 23. Employee Health & Hygiene: Cuts • When Somebody Cuts Their Finger While Harvesting and it Bleeds, What Should You Do? • Remove Worker From Harvest Area to Treat and Cover Wound • Wound Should be Bandaged & Gloved Before Continuing Work • Border Off Area & Don’t Harvest Contaminated Product
  24. 24. Worker Hygiene: Wounds & Bandages • Maintain adequate supply of bandages • Arms, wrists, or forearms that have an infected wound should be covered with a dry, tight fitting, waterproof bandage and an outer covering for the entire bandage • A wound that contains pus and is located on a part of the body that could contact produce, processing equipment or tools presents a contamination risk. • A worker with a wound that cannot be adequately covered to prevent contact with produce, processing equipment, or tools should not work with produce, processing equipment or tools until the wound has healed.
  25. 25. Viruses • Easily spread person to person or by contamination of food or water • Viruses are shed primarily in human feces • Viruses in food are generally evidence of fecal contamination • Key is to prevent fecal contamination of food • Spread often occurs through infected food worker
  26. 26. The Hand Washing Facility • The hand washing facility must be accessible at all times • Do not block hand washing facility for any reason: – Equipment storage – Farm or Harvest – Tables and carts, etc. • Have plenty of reserve, potable water on hand or refill containers routinely • Remember: Use of hand sanitizers is not hand washing!
  27. 27. Portable Toilets • Should be provided if restroom is not easily accessible • Adequate # of field latrines should be provided, strategically located, and serviced routinely • Use caution when servicing portable toilets to prevent leakage into the field
  28. 28. Field Toilet or Restroom Placement • Should be easily accessible to employees • Remove units from field for sewage collection and servicing • DO NOT locate near irrigation water sources Gardeners need to be able to use toilet facilities whenever they need…This decreases the likelihood of employees relieving themselves in the field and causing contamination of food products
  29. 29. Water and Flooding
  30. 30. Water destined for agricultural production can easily get contaminated with human and/or animal feces by direct or indirect routes.
  31. 31. Sources of Contamination #1= Water Anytime water comes in contact with fresh produce, the water’s quality determines the potential for pathogen contamination, since water may be a carrier of a number of types of microorganisms.
  32. 32. Agricultural Water • Usually, water for agricultural uses comes from: – Surface sources such as rivers, streams, irrigation ditches, ponds, and canals – Reservoirs (open or capped) – Municipal water systems
  33. 33. If you use surface water •Test water quarterly for fecal coliforms and keep records of all water test results. • Take a close look at where your water lies in relation to potential sources of contaminants.
  34. 34. Ground water may be contaminated by a variety of biological and chemical hazards, which include: • Bacteria and viruses • Domestic waste • Nitrate nitrogen • Synthetic organic chemicals • Heavy metals • Petroleum residues • Combustion products from roadways
  35. 35. Spray Water Quality • Use potable (drinking) water for pesticide sprays. • When potable water is not available, test water quality and keep records. • Low water volumes reduce risk.
  36. 36. Flooding • Crops in close proximity to soil can easily be contaminated by direct contact with flood waters. • FDA considers ready-to eat crops (such as leafy greens and melons) that have contacted flood water to be adulterated. • These crops are to be excluded from the food supply.
  37. 37. Flooding • Consider potential contamination of crops from agricultural run-off (i.e. manure piles, etc.) • Prevent cross- contamination by (equipment or humans) from flooded areas to non-flooded areas • Allow flooded soils to dry sufficiently and be reworked prior to planting additional crops
  38. 38. If you have any concerns about your water … Microbiological testing is used in the verification steps of a safety assurance program. It is important to document the frequency and results of each water test for comparison purposes. These records would become very important in the event of a microbiological outbreak investigation.
  39. 39. Recommended Draft Guidelines on Water Testing for The Produce Industry Preharvest/harvest water that contacts EDIBLE portions of the produce (i.e., water used exclusively for irrigation and/or in pesticide sprays for products such as lettuce and other leafy greens.) – Generic E. Coli <235 cfu*/100 ml sample of generic E. Coli for a single sample or <126 cfu/100 ml sample geometric mean. – Where surface water is used for irrigation, monthly tests are recommended minimum frequency. *Colony forming units
  40. 40. Recommended Draft Guidelines on Water Testing for The Produce Industry Preharvest/harvest water that DOES NOT contact edible portions of the produce (such as irrigation water for melons, apples, etc.) such as that used in drip or furrow irrigation. – Generic E. Coli <576 cfu*/100 ml sample of generic E. Coli for a single sample or <126 cfu/100 ml sample geometric mean. – Where surface water is used for irrigation, monthly tests are recommended minimum frequency *Colony forming units
  41. 41. Recommended Draft Guidelines on Water Testing for The Produce Industry Post Harvest Water, such as that used by processors or on-site sampling and cutting /processing. – Water must meet standards for potable (drinking) water.
  42. 42. If Tests of Preharvest/Harvest Water are Found to Exceed Recommendations • Consider an alternative water source. • Investigate what is causing the elevated microbial counts. • Have irrigated crops tested for common human pathogens (E. Coli, salmonella etc.).
  43. 43. Water Source Will Determine the Possible Frequency of Testing Source Possible Water Testing Frequency* Closed-system, under the ground or covered tank One annual test at the beginning of season Uncovered well, open canal, water reservoir, collection pond Suggested once per month during the season Municipal/District water system Keep records from the municipality/district water system (monthly, quarterly or annual report)
  44. 44. Chlorination • Everything that is harvested does not need to be sanitized or chlorinated! • The need depends on how the produce will be marketed.
  45. 45. Singular critical control point capable of amplifying an error in sanitation or hygiene management Suslow, UC Davis Postharvest & Processing Water
  46. 46. The Problem with Water Handling Systems … • Produce from the field usually harbors many pathogens (including dirty and decaying produce). • Postharvest handling of fruits & vegetables often includes cooling using water and washing. • Pathogens can quickly accumulate in these water sources and contaminate healthy fruit.
  47. 47. Wash Water Quality • Use potable water for all produce washing, cooling, dipping, icing, and processing. •Avoid water temperatures in dump tanks that are more than 10°F cooler than produce.
  48. 48. Fruit pulp must be < 10oF warmer than water temperature to prevent infiltration. Warm fruit contracts in cold water pulling water and microbes into the fruit. Bacteria can enter the stem scar or can be drawn into the pulp of produce if not handled properly
  49. 49. Soil, Manure, and Compost
  50. 50. Survival of Human Pathogens in Manure • Pathogens have been reported to survive in manure for one year or longer. • No one knows precisely how long manure borne pathogens survive after application to fields. • Where it is not possible to maximize the time between application and harvest, raw manure should not be used.
  51. 51. Use of Municipal Biosolids on Food Crops - Don’t Do It! • If you are growing produce close to your house or are a home processor, know where your septic system is. – Are you growing crops over it? – Is the septic system failing?
  52. 52. Compost vs. Manure Unless the compost has been produced under very strictly regulated circumstances then it is manure and should be treated as such.
  53. 53. So what makes manure compost? C:N Ratio - between 25:1 and 40:1 If using windrow system, achieve between 1310 to 1700 F for at least 15 days. Compost must be turned 5 times during the process.
  54. 54. Sanitation in the Field • Site selection and maintenance • Production practices – Irrigation – Fertilization • Harvest operations 3 Areas of Concern
  55. 55. Site selection and maintenance • Land use history – grazing animals – exposure to hazardous chemicals • Current proximity to livestock operations • Keep cull piles, refuse dumps, and debris away from production fields • Provide facilities for worker sanitation- bathroom and handwash facilities
  56. 56. Manure = Fecal Matter = Microbes • Human or animal: DO EVERYTHING you can to keep manure off produce. • Preventing contamination is the goal.
  57. 57. Exclude Animals Keep wildlife out of production areas as much as possible.
  58. 58. Keeping Animals Out • Maintain domestic and farm animals away from production fields and packing facilities and establish physical barriers or vegetation to avoid animal entry. (Especially important in the field near harvest) • Workers should not be allowed to bring dogs, cats or other domestic animals into the production field, packaging or storage facilities. • Dead or trapped animals such as birds, insects, rats, etc. should be disposed of promptly in order to avoid attracting other animals. Proper disposal procedures are to bury or incinerate the animal.
  59. 59. Compost Application • There are no restrictions in terms of days between application and harvest for properly produced compost. • Leafy greens crops are particularly prone to contamination and require the highest level of caution and management
  60. 60. Incorporate Manure • Broadcast • Disk • Moldboard Plow Note contamination from dust
  61. 61. Target Time of Application  Apply manure in fall or after produce crop is harvested  Do not apply to produce crops just prior to crop establishment - - but apply to non-food crops.  Do not harvest fruits or vegetables until 120 days after application if fruits or vegetables contact soil. – 90 days if no soil contact.  Keep records
  62. 62. Choose Appropriate Crops  Avoid growing root and leafy green crops in the year that manure is applied  Apply manure to perennial crops in the planting year only  Keep records
  63. 63. Heavy Metals in Garden Soil • Know site history • Test for heavy metal concentrations – Know test limitations (recovery %) • Potential for heavy metal consumption is almost exclusively through soil consumption • Remediate where necessary
  64. 64. Heavy Metals in Garden Soil
  65. 65. Harvest/Post-Harvest
  66. 66. Harvest Considerations • Ideally pick dry fruits or vegetables. • Leave produce that has bird droppings on it. • Clean and sanitize totes before use • Cool product quickly.
  67. 67. Punctured or Bruised Produce Provides the Entry for: • Plant Pathogens • Foodborne Illness Pathogens Proper harvesting/culling is important to produce safety and quality.
  68. 68. Temperature Management • Low temperatures supplement good sanitation practices • Avoid delays that postpone cooling • Consider: – Time from harvest to packinghouse – Time from arrival to cooling of produce – Speed of cooling & final temperature
  69. 69. Temperature Management • Storage and transport temperatures – Optimum temperatures for fruits and vegetables range from 32°F/0°C to 59°F/15°C – Most human pathogens grow slowly or not at all below 45°F/7°C – Listeria monocytogenes is a special concern in refrigerated environments
  70. 70. All products are harmed by exposure to excessively high and low temperatures. Temperate commodities should ideally be transported/stored at 32°F to 38°F (0°C-3°C). Tropical and subtropical products must be transported at higher temperatures to avoid chilling injury. Effects of Temperature on Horticultural Commodities
  71. 71. Specific recommendations for a few crops More can be found here: ucefacts/
  72. 72. Tomatoes • Cooling: Room • Storage: 48-50 degrees F • Optimum humidity 85-95 percent • Shelf life: 2 to 4 days after ripening
  73. 73. Peppers • Cooling: Forced air or room cooling • Storage: 45 to 50 F • Optimum humidity: 90 to 95% • Shelf life: 2 to 3 weeks
  74. 74. Sweet corn • Cooling: Refrigerate immediately or ice • Storage: 32 degrees F • Optimum humidity: 90 to 98% • Shelf life: 5 to 7 days for standard varieties; 8 to 12 days for supersweet varieties
  75. 75. Cabbage and leafy greens • Cooling: Room cooling, hydrocooling, and icing. (Icing is suitable for leafy greens only.) • Storage: 32 F • Optimum humidity: 95% • Shelf life: Cabbage - 2 to 3 months Leafy greens - 1 to 2 weeks
  76. 76. Green beans and peas • Cooling method: Hydrocooling, Forced-air cooling • Storage temperature: 37 to 45 F • Optimum humidity: 95% • Shelf life: 5 to 10 days
  77. 77. Onions • Drying conditions: Temperature: 100 F Relative humidity: 65% • Storage conditions: 32 F • Relative humidity: 70% • Storage life: Refrigerated 2 to 3 months Controlled atmosphere 6 to 8 months
  78. 78. Apples • Cooling: Forced air, hydrocooling (room cooling acceptable) • Storage: 30 F to 40 F, depending on variety • Optimum humidity: 90 to 95% • Shelf life: 1 to 12 months
  79. 79. Thank You Marlin A. Bates K-State Research and Extension Horticulture Agent – Douglas County