Worldwide growers should follow Good Agricultural Practices (GAPs) and Good Handling Practices (GHPs) when handling fresh produce to minimize contamination.
Water is an ideal source for pathogens to contaminate the produce that reach the consumer. Pathogens can survive long periods in water and travel over a larger area using water as a source. Thereby allowing to contact the pre and post-harvest produce through contamination. Hence, the quality of water consistently determines the potential of contamination by pathogens as water could carry many different microorganisms that are harmful to human health.
It is estimated that tiny amounts of microorganisms (as few as 10 to100 cells) in water could cause foodborne illness. Contamination could happen at pre-harvest in field operations, such as irrigation, fertilizer/pesticide applications, frost control and cooling. It could also occur during post-harvest activities, such as product rinsing, washing, cooling and transport.
The quality of agricultural water varies and it highly depends upon the source of the water. Surface water has the highest probability of being contaminated, while groundwater is of moderate risk, and municipal water is considered low risk. Indirect water application (non-crop contact) on crop planted growbags, such as drip irrigation are at a very low risk of being contaminated.
There are few ways to minimize water contamination of crops. Drip irrigation is a one particular method that prevents contamination from product contact and soil splash. Furthermore, avoiding irrigation one week before harvest could help minimize contamination to a considerable extent. Maximization of the time between irrigation and harvest would help to reduce contamination due to dryness and exposure to solar radiation, which increases the rate of inactivation or death of pathogens in the water. Moreover, another good practice to follow in order to reduce water contamination in the product is to periodically conduct a laboratory test on the water that is being used for the crops for elements such as generic E. coli.
In general, surface water should also be tested once a month over the growing season, specifically during planting, peak use and right before the harvest. Well water should be tested once every three months whilst municipal water is assumed safe.
Microbial standards of water used for agricultural teas, sprout or mushrooms on food contact surfaces require a no detectable generic E. coli content per 100 milliliters of water. Irrigation water requires to have not more than 235 colony forming units (CFU) of generic E. coli per 100 milliliters of any single water sample.