Transcript Food Safety and Postharvest Handling for Organic Crops

Food Safety and
Post harvest Handling for
Organic Crops
W. C. Morris
Department of
Food Science and Technology
Why The Concern?
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5000 deaths
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6 – 81 million illnesses
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325,000 hospitalized
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Costs : $6.5 - $34.9 billion annually
CDC
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.
Major Areas of Concern
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Water
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Manure and Municipal Biosolids
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Worker Health and Hygiene
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Sanitary Facilities
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Field Sanitation
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Packing Facility Sanitation
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Transportation
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Traceback
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”
FDA Good Agricultural
Practices (GAPs) Guidelines
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Published by the FDA
in 1998 as a guidance
document for produce
growers, packers and
shippers in the U.S.
What are GAPs?
Irrigation
Employee Hygiene
Cooling
Good Agricultural
Practices (GAPs) are
sanitary procedures used
during crop production,
harvesting, packing and
shipping to prevent or
minimize produce
contamination with human
pathogens.
Important Considerations
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Focus is only on microbial hazards
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Focus is on risk reduction, not elimination
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Based on broad scientific principles
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Must keep up with new information and
technologies
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Pest Control
Water Quality and Safety
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Be aware of potential sources of pathogens from
your water sources
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Maintain wells in good condition
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Be aware of current & historical use of land
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Consider practices to protect water quality
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Consider irrigation water quality & use
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Microbial testing of water
Water Testing
Flowing Water (rivers, streams)
4 times per year
Impounded Water (ponds, lakes)
3 times per year before season begins
Processing Water
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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
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Consider the water temperature for certain
produce
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Maintain efficacy of antimicrobials
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Use appropriate wash methods
Contamination
from Manure
Application Timing
Proper Composting
Source of Manure
From Cornell GAPs program – used with permission.
There are many
opportunities for
fresh produce to
be contaminated
by farm workers
Farm Worker
Hygiene
Courtesy of Trevor Suslow
Field Sanitation
Clean harvest
containers and tools
daily.
Transportation Issues
Precooling, sanitation
and proper air delivery
are very important to
maintain the quality
and safety of produce.
Traceability
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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?
Source Verification
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Where did it come from?
Who produced it?
Who handled it?
Bar Codes
Third Party Audits
GAPs
Sources of GAP Audits
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USDA and State Ag. Departments
ABC labs of Gainesville, FL
AIB of Iowa
Primus Labs in CA
Davis Technology in CA
Others.
Post Harvest Handling
Production Practices
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Seed selection and cultivar selection
Cultural practices
Environmental Conditions at fruit set
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Wind
Frost
Rain
Management Practices
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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
Harvest Handling
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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)
Post Harvest and Storage Consideration
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Temperature
Packaging
Chilling injury
Preventing moisture loss
Sanitation
Ethylene
Mixed loads
Storage of crops
Temperature
Single Most Important Factor
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Refrigeration retards:
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Aging
Undesirable metabolic changes
Moisture loss
Spoilage from bacteria, fungi and yeasts
Undesirable growth, i.e. sprouting
Pre-cooling
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First important step
To lowest safe temperature ASAP - critical for
crops with high respiration rates:
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Broccoli
Asparagus
Green beans
Mushrooms
Sweet corn
Room Cooling
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Not as efficient as some
Good as a pre-cooling method
Need good air circulation around containers
Forced Air Cooling
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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
Hydro-cooling
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Very efficient method of cooling (removes heat 5
times faster than air but less energy-efficient)
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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
Top or Liquid Icing
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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
Vacuum Cooling
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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
Chilling Injury
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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
Chilling Injury
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Very sensitive crops are:
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Basil
Cucumber
Eggplants
Pumpkins
Summer squash
Okra
Sweet potatoes
Chilling Injury
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Moderately sensitive:
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Snap beans
Cantaloupe
Peppers
Winter squash
Tomatoes
Watermelon
Preventing Moisture Loss
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Important in controlling moisture loss
Best range 80 -90% R. H.
Difficult for small producers
Sanitation becomes even more critical
Cool temperature important
Use a hygrometer to measure
Sanitation
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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
Ethylene
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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
Mixed Loads
Combine only products that
are compatible with respect to:
TEMPERATURE
Relative humidity
Oxygen and carbon dioxide
Protect from odors
Ethylene protection
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Summary
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Quality cannot be improved post
harvest
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Food Safety begins in the field
(GAP’s)
Summary (continued)
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High Quality and Good Shelf Life Depends On:
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Sound production practices
Proper handling during harvest
Appropriate post harvest handling and storage
 Key Factors
 Temperature
 Relative humidity