Consider the risks associated with animal intrusion in fields before harvest

Learn more about the risks associated with the three main types of animal intrusion a grower may find during a preharvest wildlife assessment.

Wildlife tracks in a field
Photo by Phil Tocco, MSU Extension

Animal activity on the farm can be a huge risk to food safety when growing fruits and vegetables, which is why preharvest wildlife scouting is so important. The Food Safety Modernization Act (FSMA) Produce Safety Rule requires fresh produce growers visually examine their fields and covered produce for signs of potential contamination (CFR 112.83 (b)), and that they take all measures reasonably necessary to identify, and not harvest, covered produce that is likely to be contaminated with animal excreta (CFR 112.112).

How do growers determine, though, what crops are safe to harvest versus what crops are likely to be contaminated? It’s important to consider the type and severity of the animal intrusion in fields before harvest.

Three types of animal intrusion you might find include animal tracks, crop damage and animal scat or feces. In the case of animal tracks, only one instance of tracks in the field carries a relatively low risk. On the other hand, sporadic or widespread animal tracks carry a moderate risk, and a no-harvest buffer zone may need to be created around nearby crops.

Crop damage, such as bite marks or trampled plants, is riskier than animal tracks. Sporadic evidence, such as a few observations of trampled plants throughout the field, is moderately risky. Widespread crop damage is a high risk and indicates significant evidence of contamination. Marking and avoiding harvest around high risk areas of crop damage is a good strategy to reduce the potential for contamination. 

Risks associated with fecal matter in the field are the highest. For even just one instance of fecal matter, the risk of contamination is moderate. Widespread evidence of fecal contamination is very high risk and would justify marking the contaminated area and creating a no-harvest buffer zone around the area where significant feces was found.

To learn more, this interactive video made by Michigan State University Extension leads viewers through a simulated preharvest wildlife assessment of a carrot field. This hands-on approach allows the viewer to choose where to scout within the field, record any observations they find, and make a final decision on what to harvest in order to maximize safety and profitability.

Risks posed by wildlife cannot be eliminated, but they can be managed through a common-sense preharvest wildlife scouting program. By taking action and avoiding harvest around significant areas wildlife damage, produce will be much safer to eat. 

If you have specific questions about the Produce Safety Rule or have difficulty tailoring GAPs to your farm, you are welcome to contact the Agrifood Safety Work Group at or 517-788-4292.

Funding for this article was made possible, in part, by the Food and Drug Administration through grant PAR-16-137. The views expressed in the written materials do not necessarily reflect the official policies if the Department of Health and Human Services; nor does any mention of trade names, commercial practices or organization imply endorsement by the United States Government.

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