- Malheur Experiment Station
Food safety begins with proper growing practices. The source of irrigation water should be safe for its intended use, either to irrigate (non-potable water) or to wash crops (potable water). Water contacting produce should be monitored to prevent pathogen contamination and foodborne illnesses. Where water quality cannot be controlled, it is best to minimize contamination risks by identifying and diverting sources for contamination dangers (e.g. nearby manure runoff from cattle ranch). However, for onion growing, there is evidence that survival of some serious waterborne pathogens on the surface of raw onions can be restricted. Natural antimicrobial characteristics of onion bulbs have been found to limit survival of harmful bacteria such as E. coli and Salmonella (Azu, 2007). Also, pathogens in irrigation water that get onto produce may die off by the time of harvest. A recent study showed that onions inoculated early in the growing season with high levels of Escherichia coli 0157:H7 bacteria in sprinkled irrigation water harbored decreasing counts of the bacteria over a period of several weeks; by harvest time, E. coli bacteria counts were not detectable (Islam, 2004). However, it is important to note that even low counts of harmful bacteria can cause sickness.
Other areas of food safety during the growing process include correct use of pesticides, insecticides, fertilizers, and other necessary chemicals. Food safety and sustainable practices are maintained by knowing when to apply, how much to apply, and keeping record of the amount of chemicals that have already been applied.
For growing practices involving the use of animal manure (required for certified organic growing practices), specific provisions must be taken to prevent pathogens and parasites from infecting humans. For onion production, raw manure cannot be used unless it is composted or if the time between application and harvest is at least 120 days. Additionally, the use of dog, cat, or pig manure is prohibited (“Manure Facts - Organic Trade Association,” n.d.). Observing these provisions will minimize the risk of adulterating the food supply and harming the consumer.
During harvest, there are necessary precautions that can prevent contamination. It is important that employees are properly trained for their duties and that growers observe the GAPs and a Farm Food Safety Plan. Proper use of facilities should be enforced. Workers should be taught proper hygiene when returning from restrooms, and employers should make functioning restroom and hand-washing facilities (with potable water) available (Daeschel, 2013). Employees should be taught about blood-borne pathogens and how to prevent their spread. If an employee is sick, he or she should not handle produce or be near other employees; the risk of infecting others and spreading disease to food supply is high (Food Safety Initiative Staff- Food and Drug Administration, 1998). Totes and crates used to carry onions should be sanitized to eliminate possible pathogens and bacterial growth. Proper sorting of damaged, bruised, or punctured produce will help to ensure quality of food while preventing foodborne pathogens from entering and spreading among the food supply (Daeschel, 2013).