1. Food Safety and Post harvest Handling for Organic Crops
W. C. Morris
Department of
Food Science and Technology

2. Why The Concern? 5000 deaths 6 – 81 million illnesses
325,000 hospitalized
Costs : $6.5 - $34.9 billion annually
CDC

4. Contamination and Organic Food
Are there hidden dangers?
CDC reports that those eating “organic” foods are eight times more likely to be attacked by E. coli 0157:H7
A University of Minnesota study showed organically grown produce had 9.7% positive samples for E. coli 0157:H7 compared to 1.6% for conventional produce from farms in Minnesota.

5. Major Areas of Concern Water Manure and Municipal Biosolids
Worker Health and Hygiene
Sanitary Facilities
Field Sanitation
Packing Facility Sanitation
Transportation
Traceback

6. Produce Identified as Area of Concern
May, 1997
USDA, EPA and Dept. of HHS
sends the President a report that
identifies produce as an area of
concern.
Resulting In: “Guide To Minimize Microbial Food Safety Hazards For Fresh Fruits and Vegetables”

7. FDA Good Agricultural Practices (GAPs) Guidelines
Published by the FDA in 1998 as a guidance document for produce growers, packers and shippers in the U.S.

8. What are GAPs?
Good Agricultural Practices (GAPs) are sanitary procedures used during crop production, harvesting, packing and shipping to prevent or minimize produce contamination with human pathogens.
Irrigation
Employee Hygiene
Cooling

9. Important Considerations
Focus is only on microbial hazards
Focus is on risk reduction, not elimination
Based on broad scientific principles
Must keep up with new information and technologies
Pest Control

10. Water Quality and Safety
Be aware of potential sources of pathogens from your water sources
Maintain wells in good condition
Be aware of current & historical use of land
Consider practices to protect water quality
Consider irrigation water quality & use
Microbial testing of water

11. Water Testing Flowing Water (rivers, streams)
4 times per year
Impounded Water (ponds, lakes)
3 times per year before season begins

12. Processing Water Practices that ensure & maintain quality
-sampling & micro. Testing
-develop SOP’s for all processes using water
-clean/sanitize water contact surfaces
-install backflow devices & legal air gaps
-routinely inspect equipment used to maintain quality
Consider the water temperature for certain produce
Maintain efficacy of antimicrobials
Use appropriate wash methods

13. Contamination from Manure
Application Timing
Proper Composting
Source of Manure
From Cornell GAPs program – used with permission.

14. There are many opportunities for fresh produce to be contaminated by farm workers
Farm Worker Hygiene
Courtesy of Trevor Suslow

15. Clean harvest containers and tools daily.
Field Sanitation
Clean harvest containers and tools daily.

16. Transportation Issues
Precooling, sanitation and proper air delivery are very important to maintain the quality and safety of produce.

17. Traceability
Is a system of trace back available for the finished product?
Is the finished product traceable to the packing house?
Is the finished product traceable to the specific grower?
Is the finished product traceable to the specific orchard or field?
Is the packing date identified on the finished product?
Is the harvest date traceable?

18. Source Verification Where did it come from? Who produced it?
Who handled it?
Bar Codes

19. Third Party Audits
GAPs

20. Sources of GAP Audits USDA and State Ag. Departments
ABC labs of Gainesville, FL
AIB of Iowa
Primus Labs in CA
Davis Technology in CA
Others.

22. Post Harvest Handling

23. Production Practices Seed selection and cultivar selection
Cultural practices
Environmental Conditions at fruit set
Wind
Frost
Rain

24. Management Practices Irrigation – to much or to little
High rates of nitrogen (improper soil nutrition)
Mechanical injury
Use only composted manure (60 – 120 days) depending on certifying agency and crop

25. Harvest Handling Quality cannot be improved after harvest
Harvest at proper stage and size
During the coolest part of day
Keep in shade
Handle gently (moisture loss may be as much as 400% by single blemish)

26. Post Harvest and Storage Consideration
Temperature
Packaging
Chilling injury
Preventing moisture loss
Sanitation
Ethylene
Mixed loads
Storage of crops

27. Temperature Single Most Important Factor
Refrigeration retards:
Aging
Undesirable metabolic changes
Moisture loss
Spoilage from bacteria, fungi and yeasts
Undesirable growth, i.e. sprouting

28. Pre-cooling First important step
To lowest safe temperature ASAP - critical for crops with high respiration rates:
Broccoli
Asparagus
Green beans
Mushrooms
Sweet corn

29. Room Cooling Not as efficient as some Good as a pre-cooling method
Need good air circulation around containers

30. Forced Air Cooling
Cooling rate depends on air temperature and rate of air flow
Generally 75-90% faster cooling
Note: to avoid over cooling and dehydration, do not operate forced air fans after produce has been cooled to correct temperature

31. Hydro-cooling
Very efficient method of cooling (removes heat 5 times faster than air but less energy-efficient)
Can serve as a means of cleaning
Reduces water loss
Chlorinate to reduce microorganisms
Not appropriate for: berries, potatoes, bulb onions, others not suited to wetting

32. Top or Liquid Icing
Especially effective on dense products and palletized products difficult to cool
Works well on high respiration products: sweet corn, broccoli
One pound of ice cools ~three pounds of produce

33. Vacuum Cooling Water leaves crop and take heat with it
Produce sprayed with water first = “Hydrovac Cooling”
Good for leafy vegetable which have a high surface-to-volume ratio, i.e. greens

34. Chilling Injury Some vegetables best stored just above freezing
Others best stored at 45°F-55°F
Both time and temperature involved
Effects of chilling injury are cumulative

35. Chilling Injury Very sensitive crops are: Basil Cucumber Eggplants
Pumpkins
Summer squash
Okra
Sweet potatoes

36. Chilling Injury Moderately sensitive: Snap beans Cantaloupe Peppers
Winter squash
Tomatoes
Watermelon

37. Preventing Moisture Loss
Important in controlling moisture loss
Best range % R. H.
Difficult for small producers
Sanitation becomes even more critical
Cool temperature important
Use a hygrometer to measure

38. Sanitation Chlorine is most often used
Pathogens traced to fresh fruit and vegetables:
E. coli 0157:H7
Salmonella
Cryptosporidium
Hepatitis
Cyclospora
Chlorine is most often used
Caution – organic growers, it is a restricted material
Ozone
Hydrogen peroxide

39. Ethylene Natural hormone produced by some fruits
Damaged fruit produces more
Do not store ethylene producers with fruits and vegetables that are sensitive
Ethylene producers: apples, cantaloupes, peaches, pears, plums, tomatoes

40. Mixed Loads Combine only products that are compatible with respect to:
TEMPERATURE
Relative humidity
Oxygen and carbon dioxide
Protect from odors
Ethylene protection

41. Summary Quality cannot be improved post harvest
Food Safety begins in the field (GAP’s)

42. Summary (continued) High Quality and Good Shelf Life Depends On:
Sound production practices
Proper handling during harvest
Appropriate post harvest handling and storage
Key Factors
Temperature
Relative humidity