Post-harvest: Resource materials include management of personnel, proper clean-up and disinfection methods, and food handling education and training materials.
Post Harvest Recommendations
Chemicals and Sanitizers for Washing Fruits
Follow scientifically valid chemical concentration and contact time parameters for washing fruits (parameters can be based on regulation, industry guidance and/or scientific studies). For example, sodium hypochlorite concentration should not exceed 200 ppm free chlorine when used as sanitizing solution according to CFR title 21, Chapter I, Subchapter B, Part 178. In the USDA Good Agricultural Practices and Good Handling Practices Audit Verification Program, chlorine is mentioned to be added to water for post-harvest treatment of fresh produce at 50 -200 ppm total chlorine for 1 to 2 minutes.
1. Always adapt the concentration and contact time as prescribed for each type of fruit.
Managing Organic Waste Materials on Farm and in Processing Areas
Residual organic matter such as rejected fruits, cut parts of the harvest, etc., generated from cleaning and processing activities can become a source of contamination
2. These areas should be routinely cleaned and/or disinfected.
3. Avoid accumulating and holding organic waste for more than a day as this increases the risk of contamination.
Monitoring Microbial Quality of Processing Water
Monitor the microbial quality of processing water in direct contact with fruit periodically.
1. When test results indicate fecal contamination, test the water for Hepatitis A virus (HAV) and Norovirus (NoV).
2. If virus contamination is confirmed, consider change water source, hold activities involving water, and notify health authorities.
Washing of Produce
Use an appropriate washing method to reduce the microbial load on fresh produce.
1. For produce not easily bruised or injured, immersion bath is generally preferred than sprays due to the better surface coverage.
2. If an immersion tank is used, the wash water in water tank shall be replaced regularly to avoid cross-contamination from one batch to another.
3. Water quality should be maintained to not to introduce contamination in all washing systems.
4. To decide when to refresh water, either measure turbidity or monitor the water visually with a clearly defined criteria (e.g.: a photo of water with organic matter build-up that need refreshing).
5. If possible, use a series of washes with antimicrobial chemical to achieve a better result.
The storage unit of water must be maintained and disinfected regularly to ensure the good microbial quality of water.
Water used for Post-Harvest Operations
Use potable water for all cleaning and washing activities.
1. If potable water is not available or water is recirculated, treat the water with effective disinfectant before using, such as chlorine or ozone.
2. Untreated surface water must not be used for any activities post-harvest.
3. Monitor the microbial quality of treated water and the concentration of disinfectant added frequently to prevent the wash water to become the source of contamination.
4. When measuring the concentration of disinfectant, choose a method that can give a value of concentration, such as titration or colorimeter instead of test strips which can only estimate a range of concentration.
Water used in Wash Tanks
Water used in the wash tank (dump tank) should be warmer than the fruit being washed so as to reduce the infiltration of wash water into the fruit. When infiltration occurs, cold water creates air pockets within the produce which lead to a pressure differential that pulls water into the produce, microorganisms in wash water may be pulled into spaces inside the produce and subsequent washing steps will not be able to reduce these microorganisms.
1. Monitor the temperature of water to ensure it is always warmer than fruit being washed or cool the fruit before washing.