Prevention of Food-Borne Illness Begins on the Farm

August 1997

PREVENTION OF FOODBORNE ILLNESS
BEGINS ON THE FARM

Outbreaks of foodborne illness are making headlines on a regular basis. Hepatitis in strawberries, E. coli in apple juice and lettuce, and Cyclosporeae in raspberries have shaken consumer confidence in the safety of the food supply. As many as 30 million people contract some type of foodborne illness each year - most cases are not diagnosed or reported, and are probably just thought to be "stomach flu." However, up to 9,000 people die from foodborne illness each year.

Fruits and vegetables may be harvested on a farm, processed in one plant, repackaged in another, and served by an institution or in the home. They may be hand harvested, stored, and displayed in a store prior to home preparation. Each of these steps is an opportunity for a pathogen to enter the food supply.

How much foodborne illness originates on the farm? No one knows.

Are there reasonable steps that a grower can take to reduce the risk that a pathogen will contaminate the food produced on the farm? Absolutely.

Clean Soil

The improper use of manure is a large risk factor contributing to foodborne illness. Pathogens such as E. coli, Salmonella and Campylobacter can be present in slurry and soil for up to 3 months, depending on temperature and soil conditions. Troubling for growers is the

fact that Listeria may survive on vegetables growing in the soil, even though it may not survive in the soil itself. Yersinia may survive, but not grow, in soil for up to 330 days. Composting manure, incorporating it prior to planting, and avoiding top-dressing are important steps that can reduce the risk of contamination while making use of this important source of nutrients.

Clean Water

Make sure that water used in overhead irrigation, produce cooling, washing, dipping and processing operations is clean. Where possible, use chlorinated water or groundwater. Surface water close to untreated sewage or a livestock operation should be tested. (Contact your county Extension office for water testing services, or look in the yellow pages of your telephone book.)

Clean Hands

The failure of food handlers to wash hands after using the restroom or when infected with the hepatitis virus has been the cause of outbreaks of foodborne illness as well. Attention should be paid to worker hygiene, not only in the packing house, but in the field as well. Provide soap and clean water in the field, and insist that all workers wash hands before handling fruits and vegetables.

Minimizing Pathogen Contamination During Production of Fresh Vegetables and Fruits

PRE PLANT

Manure Source / Type

Slurry - store for 60 days in summer or 90 days in winter prior to field application.

Fresh - incorporate into soil.

Compost - most pathogens killed within days by high temperatures during aerobic composting.

Manure Application Time

Fall - preferably onto cover crop to minimize erosion / nutrient losses.

Spring- preferably onto agronomic rotation crop. If applied to vegetable or fruit ground, incorporate.

Do NOT harvest within 60 days of manure application.

Manure Incorporation

Poor survivability of most pathogens in soils.

Crop Choice

Avoid root / leafy crops in year manure applied.

Preferable to apply manures to agronomic rotation crop.

Perennial crops - minimal risk with manure incorporation and harvest delay.

PRODUCTION

Irrigation Water Contamination

Drip - minimizes risk since no direct crop wetting.

Overhead / well water - minimal risk if well casing is maintained and livestock excluded from pump areas.

Overhead / surface water- consider water testing if downstream from livestock operations or raw sewage.

Manure Sidedressing

ABSOLUTELY NOT fresh or slurry manure.

Compost sidedressing- OK.

Animal Exclusion

NO grazing of livestock (including poultry) during season of harvest.

Minimize wild animal traffic, where possible.

Worker Hygiene

Provide restrooms in field.

Supply antibacterial soap and fresh water for hand washing and enforce use.

HARVEST

Storage Facilities

Clean and sanitize prior to harvest.

Bins / Containers

High pressure wash and sanitize prior to harvest.

Store bins in full sun (ultraviolet rays destroy several pathogens).

No standing in bins during harvest.

Worker Hygiene

Provide restroom facilities in the field.

Supply antibacterial soap and fresh water for hand washing and enforce use.

U-Pick Operations

Promote cleanliness - encourage customer hand washing prior to entering fields.

Provide antibacterial soap for hand washing in field and in restrooms.

Provide clean and convenient restrooms for customer use.

Drops and Damaged Produce

Do not use decayed, damaged or wormy produce.

POST HARVEST

Worker Hygiene

Provide restroom facilities.

Supply antibacterial soap / fresh water for hand washing and enforce use.

Washing / Packing Lines

Use chlorinated wash water.

Monitor chlorine levels to maintain 100 ppm solution.

Packing House Sanitation

Clean and sanitize packing areas daily.

Exclude all animals, especially rodents.

No smoking or eating in packing area.

Produce Cooling / Storage

Cool product quickly to minimize growth of any potential pathogens.

Store at appropriate temperatures to maintain product quality and minimize pathogen growth.

This page was last updated on 10/08/01.

August 1997