Food Safety and Post harvest Handling for

Organic Crops

W. C. MorrisDepartment of

Food Science and Technology

Why The Concern?

5000 deaths 6 – 81 million illnesses 325,000 hospitalized 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 Water Manure and Municipal Biosolids Worker Health and Hygiene Sanitary Facilities Field Sanitation Packing Facility Sanitation Transportation Traceback

Produce Identified asArea of Concern

May, 1997USDA, EPA and Dept. of HHSsends 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

Published by the FDA in 1998 as a guidance document for produce growers, packers and shippers in the U.S.

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.

Employee Hygiene

Cooling

Irrigation

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

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

Water Testing Flowing Water (rivers, streams)

4 times per year

Impounded Water (ponds, lakes)3 times per year before season begins

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

Contaminationfrom Manure

Proper Composting

Application Timing

Source of ManureFrom Cornell GAPs program – used with permission.

Farm Worker Hygiene

There are many opportunities for fresh produce to be contaminated by farm workers

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

1. Is a system of trace back available for the finished product?

2. Is the finished product traceable to the packing house?

3. Is the finished product traceable to the specific grower?

4. Is the finished product traceable to the specific orchard or field?

5. Is the packing date identified on the finished product?

6. Is the harvest date traceable?

Source Verification Where did it come from? Who produced it? Who handled it?

Bar Codes

Third Party Audits

GAPs

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.

Post Harvest Handling

Production Practices Seed selection and cultivar selection Cultural practices Environmental Conditions at fruit set

Wind Frost Rain

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

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)

Post Harvest and Storage Consideration

• Temperature• Packaging• Chilling injury• Preventing moisture loss• Sanitation• Ethylene• Mixed loads• Storage of crops

TemperatureSingle Most Important Factor Refrigeration retards:

Aging Undesirable metabolic changes Moisture loss Spoilage from bacteria, fungi and yeasts Undesirable growth, i.e. sprouting

Pre-cooling First important step To lowest safe temperature ASAP - critical for

crops with high respiration rates: Broccoli Asparagus Green beans Mushrooms Sweet corn

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

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

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

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

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

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

Chilling Injury Very sensitive crops are:

Basil Cucumber Eggplants Pumpkins Summer squash Okra Sweet potatoes

Chilling Injury Moderately sensitive:

Snap beans Cantaloupe Peppers Winter squash Tomatoes Watermelon

Preventing Moisture Loss 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 Pathogens traced to fresh fruit and vegetables:

E. coli 0157:H7 Salmonella Cryptosporidium Hepatitis Cyclospora

Chlorine is most often usedCaution – organic growers, it is a restricted materialOzoneHydrogen peroxide

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

Mixed Loads Combine only products that are compatible with respect to:

TEMPERATURERelative humidityOxygen and carbon dioxideProtect from odorsEthylene protection

Summary

Quality cannot be improved post harvest

Food Safety begins in the field (GAP’s)

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