The Food and Drug Administration has made long-awaited changes to regulations that are aimed at ensuring the safety of water that’s used to grow fresh produce. 

FDA is proposing to drop the agency's original water testing standards, which were widely criticized by farmers, in favor of requirements that growers assess their water sources for potential contamination. The water regulations are required by the Food Safety Modernization Act, enacted in 2011. 

“The proposed ag water rules look to me to be risk-based,” said Donald Schaffner, extension food scientist and professor at Rutgers University, in a webinar sponsored by CONTACT, a produce safety research project at the University of Florida. He said the changes also offer more flexibility than the old rules, which though also risk-based were a “one size fits all” approach.

Under the proposal, farms would be required to assess several factors. Those include the source of water (ground versus surface), the type of distribution system (open or closed to the environment) and whether the produce is protected from sources of possible contamination, such as animals or other land uses that might add manure. 

In addition, environmental risks such as the frequency of severe weather events, high air temperatures and variable UV exposure all present different levels of risk, which would need to be assessed as part of the process.

While assessing risk involves gathering as much data as is reasonably possible, Schaffner noted that managing that risk is a different task. For the people charged with risk management, he said, the calculation must consider both probability and severity of a given risk.

The more data a risk manager has, the more informed the decision will be, but Schaffner noted that increasing the amount of testing comes with additional costs. The tricky part is finding a data collection point that will be economically feasible but satisfy the company (and the public) that the surveillance provides sufficient protection. 

More research is needed to help provide guidance for growers, Schaffner said. Work he has done, for example, can estimate differences in probability and severity of outbreaks by different pathogens.

Data generated for a fictitious pathogen can roughly mimic listeria. The likelihood that a person will get sick from listeria depends not just on whether the bacteria is present but also how likely the person is to consume the contaminated food. 

While listeria is rather common in cold smoked fish, not many people eat that regularly. Milk, on the other hand, can be contaminated with listeria if pasteurization fails, and many people consume milk every day. The cold smoked fish presents less risk, even though the probability of listeria being present in it is higher than in milk. Even a low probability of listeria in milk is a higher risk because contamination would potentially impact so many people.

Schaffner also explained how the timing of irrigation could affect the safety of oranges. The hot, humid conditions that are common in Florida’s citrus orchards, for example, favor E. coli survival. If contaminated water is applied to the oranges in those conditions, a food safety threat is likely. But when the weather is hot and dry, the bacteria's "survival probability drops. I wouldn't say instantaneously, but very, very rapidly,” Schaffner said.

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He hastened to add that this experiment was conducted in a lab, and in the real world water from a source known to be contaminated would not be applied to produce. But, he said, this type of “risk-based thinking gives us some focus and it allows us to prioritize.” 

“If we can use a risk-based system that looks at severity and probability, that's going to tell us ‘Hey, like, here are some things that maybe have a high probability and high severity.’ But maybe they're really easy to implement controls for, so that's where we should spend our money.”

While the risk-based analysis is an approach Schaffner likes, he cautions that FDA’s changes are “putting the onus on the operator to be able to do this assessment.”

Western Growers agrees. The California-based produce group, in a written statement to Agri-Pulse, said, "we appreciate the agency’s flexibility" but added that the proposed changes "place high expectations on the grower." One example Western Growers offered is that growers don't have control over adjacent land uses, which can impact their water supplies, and, therefore, their assessments. The statement also reflected Schaffner's assertion that more research and outreach will be needed "to address regional and specific risks and inform agricultural water assessments."

FDA will hold two public meetings about the proposed changes, on Feb. 14 and Feb. 25. Western Growers is forming a working group to prepare comments on the changes. FDA will take public comments until April 5.

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