The Importance of Water and Soil Safety

You may have seen in recent months that the Food and Drug Administration (FDA) has turned its focus to leafy greens, a type of produce that has become all-too associated with foodborne illness outbreaks. FDA believes the root cause of at least one of the latest California outbreaks is the presence of livestock operations “upstream” from produce growers.

Livestock defecate, and their feces flow downstream through rainfall and irrigation to surrounding crops. Leafy greens are particularly vulnerable to contamination in this manner because they grow in the ground, unlike crops whose edible, harvested parts are elevated above the ground. And leafy greens are typically eaten raw, so they lack a kill step. If the FDA is correct, then resolving this issue is not something that produce growers can do on their own. Cooperation from livestock operations is essential to addressing this problem.

But there are many steps produce growers can take to make their produce safer. And while the neighboring livestock issue might take some time to fully address, there are steps that produce growers should be taking right now if they are considered “covered farms” under FDA’s “Standards for the Growing, Harvesting, Packing and Holding of Produce for Human Consumption,” found at Code of Federal Regulations, 21, 112.

Perhaps the two most important areas covered farms must address to mitigate the risk of foodborne illness are agricultural water and biological soil amendments of animal origin (BSAAO). After all, no matter how well-educated a farm’s employees are on hygiene issues, and no matter how thoroughly they wash their hands before handling produce, all such efforts will be worthless if the produce has already become contaminated in the ground.

At least once a year, and typically at the beginning of the growing season, farmers must inspect their agricultural water systems, with the goal of ensuring that the water is safe and of adequate sanitary quality for its intended use. Farmers must adequately maintain their water systems and implement any necessary and appropriate measures to reduce contact of produce with pooled water. In inspecting the water system, farmers must consider factors such as the nature of the water source, the extent of the farmer’s control over that source, the degree to which the source is protected from contamination, the use of adjacent and nearby land (including those pesky livestock operations currently plaguing some of California’s growers) and the likelihood that known or reasonably foreseeable hazards could be introduced into the water by another user before it reaches the farm.

Any water that is used to irrigate sprouts, that comes into direct contact with covered produce during or after harvesting, that comes into contact with food contact surfaces, that is used to make ice that will come into contact with those surfaces or that is used for handwashing during and after harvesting, must be tested and must contain no detectable E. coli. If E. coli is detected, the water must be treated in accordance with certain criteria set forth in the regulations.

As for BSAAO, first of all, what are they? These are soil amendments, including agricultural teas, compost, manure and the like, that are made from animal feces or non-fecal animal byproducts, such as carcasses. Their use and handling depend on whether they have been properly treated to eliminate harmful pathogens. Proper treatment means treatment by a scientifically valid, controlled, physical (e.g., thermal), chemical (e.g., high alkaline pH) or biological process, or a combination of those processes.

The most robust treatment should render L. monocytogenes, Salmonella and E. coli undetectable. If that treatment method is used, then the BSAAO can be applied in any manner to covered produce (including those leafy greens) without restriction. There is a less robust treatment available, but if that method is used, then the BSAAO must be applied in a manner that minimizes the potential for contact with covered produce during and after application (that means it cannot be applied to leafy greens growing in the ground). But with either of these types of treated BSAAO, the produce can be harvested the same day that the BSAAO is applied.

Farmers should make every effort to protect their treated BSAAO from contamination. For example, it shouldn’t be stored in close proximity to untreated BSAAO, or in an area where livestock are kept or where wildlife are known to roam. If these measures aren’t feasible, then the farmer must treat the BSAAO as untreated.

Indeed, FDA defines untreated BSAAO to include treated BSAAO that has been mixed with untreated BSAAO and treated BSAAO that the farmer suspects or knows has become contaminated since treatment. Untreated BSAAO can still be used, but in a more restricted manner. There can be no contact with the harvestable part of the crop during application, and no or minimal contact thereafter, but again, the produce can be harvested the same day that the BSAAO is applied.

Last but not least, and as is virtually always the case with such regulations, farms must keep robust records documenting water treatment and maintenance, as well as management and treatment of BSAAO. It may be some time before a solution is found to the problem of contamination from upstream livestock, but records at least show FDA that the farm itself is doing all it can to prevent contamination, and can help more quickly isolate the source of any future disease outbreaks.

Editor's Note: Read more about what types of farms and produce are covered under the regulations in Jennifer Allen's previous column.