Follow Up Article – Cucumbers and Salmonella – Irrigation Water the Likely Culprit
Part 2: Monitoring Irrigation Waters
A previous blog posting discussed a foodborne illness involving cucumbers and Salmonella contamination. In that incident, surface waters used to irrigate product, as well as soil on the production site, were both found contaminated with Salmonella.
Produce and ready to eat foods are increasingly popular for their convenance, nutrition and health. However, there is no additional cooking involved, the consumer subject to any errors in source and preparation. Cases of illness involving these foods has increased past those involving raw animal foods.
This concern caused the United States Food and Drug Administration (FDA) to issue a Produce Safety Rule within the Food Safety Modernization Act. According to the FDA, farmers who are included under the Produce Safety Rule are regulated by the FDA irrigation water standards, meaning farms that grow produce like fruits, vegetables, and nuts, and meet certain sales thresholds, are required to comply with the standards for agricultural water used during growing, harvesting, packing, and holding processes
Under this rule, farms using preharvest irrigation waters must monitor and assess risk from irrigation waters and maintain these waters from contamination sources such as surface run off from livestock farms or pesticide applications or from farm equipment in the area. (There will be exemptions to this rule, such as smaller income farms or produce that is not expected to be eaten raw. Sprouts are exempt but are covered by other rules.)
Farmers must consider and control risks based on the following factors:
1. The water source, where it’s located, the type of supply (ground water or surface water – surface water can only be used for preharvest irrigation) and the type of distribution system (open or closed pipes);
2. Irrigation Method : Overhead sprinkling, drip, furrow or seepage – different methods will subject produce to contamination risks, depending on the crops root depth and the amount of irrigation needed;.
3. Time Interval: How much time elapses tween the last application of irrigated waters and harvest? Water which does not evaporate prior to harvest could stay on the produce.
4. Environment Heavy rains, pooling surface waters with sewage or sediment, or extreme weather can affect the water systems. Hot weather or high winds could also change the rate of contamination;
5. Annual Irrigation source testing – Standards are based on E. Coli testing. Those test results will impact use of the system.
6. Water Quality – preharvest irrigation water must meet specified standards. Water samples must be analyzed by a set schedule, usually yearly.
7. Worker Health and Hygiene – farm workers must be trained in health and hygiene practices such as hand washing and personal hygiene
What can food service workers take away from this discussion:
1. There are strict rules for produce irrigation – check with your supplier to be sure these rules are being satisfied. This assurance should include some type of food safety plan as well as water testing results;
2. Inspect your deliveries carefully – look for spoilage or wet produce, signs that contamination might have occurred.
3. Look carefully at international suppliers – ask for documentation on their food safety practices and inspections.