Where did the Romaine Lettuce Go?

In November 2018, shoppers in Ontario, Quebec and Nova Scotia noticed a prominent empty space in the produce wall of their local grocery store. Due to an E. coli scare linked to lettuce grown in California, romaine lettuce had been removed from shelves.

It was the third time in 2018 that E. coli outbreaks were linked to romaine lettuce.

Reasons for E. coli outbreaks

There are various ways vegetables can become contaminated. Soil or groundwater and surface water supplies used for irrigation can become contaminated by wildlife feces, livestock feces or sewer run-off/spillage.

In the U.S., the Food and Drug Agency (FDA) does not require growers to test their irrigation water for E. coli or other pathogens. Any testing is done voluntarily at the grower’s expense. Irrigation water may also be taken directly from surface water and given to plants without any treatment.

In Ontario, the Ministry of Agriculture, Food and Rural Affairs’ Good Agricultural Practices say that the frequency of testing depends on the water source, intended use and crop type, and tests should be conducted at the point of use. Testing frequency is often dependent on on-farm food safety programs or requirements of producers and frequency can vary from monthly to quarterly to yearly.

Results should show that the irrigation water complies with the fecal coliforms (E. coli) guidelines set out in the Canadian Water Quality Guidelines for Irrigation Water.

But once a year testing may not be enough to catch or prevent E. coli.

The Good Agricultural Practices say: “Water contamination is often intermittent and pathogens do not distribute uniformly in water. Therefore, even a negative test does not guarantee the absence of pathogenic bacteria. Regular testing increases the opportunity to discover contamination.”

Approximately 30% of E.coli outbreaks are due to contaminated vegetables[1].

Solutions for irrigation water

The best solution to avoid E. coli contamination is to be proactive – preventing an outbreak before it happens.

Treating irrigation water reduces the risk of an outbreak by disinfecting contaminated water.

The AVIVE system, using a hydrogen peroxide called Huwa-San® Peroxide, sanitizes water throughout the irrigation system, from source to final destination. In a peer-reviewed study, Huwa-San was shown to be as or more effective than chlorine at killing E. coli bacteria.

The second solution is prescriptive and complimentary – test the water more frequently.

Rapid microbial analysis can be done on site without sending water samples to the lab. This gives owners, growers and managers reliable and real-time data. High cATP readings can be an indicator of E. coli, prompting growers conduct a second test based on culturing techniques to confirm the presence of E. coli and take risk mitigation measures.

Solutions for process water

In Ontario, it is required that “water used for washing and cooling of fresh, ready-to-eat fruit and vegetables must be of potable quality” – quality complying with the Ontario Drinking Water Quality Standards.

Recently, SanEcoTec received a Letter of No Objection (LONO) from Health Canada for the use of its Clean5, Clean25 and Clean50 sanitizers in process water on fresh and minimally processed fruits and vegetables. The LONO is a standard form letter in response to a detailed scientific submission expressly stating that Health Canada sees no reason why the sanitizers should not be used.

In process water, the Clean line of products provide a sanitizing wash and efficacy against standard food spoiling organisms.

Next steps for growers

Water is complex, but it doesn’t need to be a mystery. SanEcoTec carries out water quality risk assessment – called a “Discovery Project” – with rapid microbiological analysis to gain insight into the unique situation of each grower. This is a small but valuable engagement for clients and the best place to start as it provides a clear baseline of key performance indicators and forms the basis of a water quality strategy.

A solution to a persistent problem

The SanEcoTec approach, with the AVIVE program, provides a reliable, battle-tested solution to the problems of E. coli outbreaks and delivers secondary business-building benefits for growers.

[1] Microbiologicalsociety.org

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