College of Agriculture and Environmental Sciences

Wildlife and Domestic Animal Risks to Produce Safety

Animals are a normal part of the farm environment, but they are a big concern for produce safety. Both domestic and wild animals can carry human pathogens in their feces and transport them into the production field, contaminating the produce with such pathogens as salmonella, E.coli O157:H7, and campylobacter jejuni, all of which have been found in animals. It’s essential to restrict their entry into the production field to avoid this danger.

In addition to direct contamination of the products in the field, animal feces may also pollute the water sources utilized during production, leading to cross-contamination of crops. Vast numbers of animals (i.e., flocks of geese, groups of deer or a large-scale cattle operation) represent extreme dangers, since they generate large amounts of fecal matter that may enter the production field through water runoff, airborne particles or cross-contamination from insects as well.

Even though domestic animals, such as dogs and cats, may be considered members of the family and may be deterrents to wildlife, they also have the potential to harbor pathogenic microorganisms. Family pets should be kept out of the packing house and the production fields, and kept away from vehicles carrying fresh produce, particularly near the harvest. While it is not practical to completely exclude animals from the field or the packing house, steps to minimize their entry should be taken.

How Do I Reduce Animal Contamination?

Conduct a risk assessment to detect risks posed by wild and domestic animals.

At the beginning of each season, every farm owner/operator must assess the hazards posed by wildlife and domestic animals in or close to the vegetable production fields. Proximity to wooded areas or water sources that attract wildlife must be considered. Any domestic animals, such as grazing livestock, chickens, or other farm animals, may pose a contamination hazard if runoff from their feces or bedding enters the production areas.

Knowing what parts of your farm are being frequented, or will possibly be frequented, by wildlife is critical to managing your operation. This may be difficult to determine, since there are many diverse wildlife species present, each having different habitats, food requirements and behaviors.

Wildlife Monitoring

Wildlife monitoring through the produce production season is important in preventing contamination and crop loss, but it also may give growers a better understanding of when and to what degree animal interruption occurs all through the season, thus allowing them to create a more viable animal management strategy.

Consider crop characteristics when checking for food safety-related issues with wildlife. Tree crops and crops developed off the ground are less likely to be contaminated by small rodents and warm-blooded animals, since they don’t grow where feces are likely to be deposited. Still, local bird populations or migrant birds, such as crows, are more likely to affect a tree crop directly.

Consider issues that might lead to increased animal movement toward crop and water sources: an unusually dry season, for example, or post-wildfire conditions that may impact animal movement patterns.

Some animals, including wildlife, pets that live outside or farm animals that get away from their pens, may enter the production field and packing areas unexpectedly. It’s important to have a plan for addressing these incidents.

Domestic Animal Risks on the Farm

Many of the standards for food safety related to wildlife equally apply to domestic animals. Keep working animals outside the production field and away from the harvest, particularly when the edible part of the crop is growing.

There are a few extra considerations to make on the farm with domesticated animals, since the producer may use them directly for the farm’s work.

Be sure that farm workers prevent animal feces from coming in contact with their hands, clothing, and shoes. The Food Safety Modernization Act (FSMA) requires that any farmworker coming in contact with working animals must take appropriate steps to reduce produce contamination, including thoroughly washing hands as soon as practical after touching or working with animal waste. The number of pathogens that domesticated animals carry can be affected by the animal’s age, species, how it was raised and other management components, but all animals have the potential to pose risks.

Assessing Risk Posed by Domesticated Animals

Are domesticated animals permitted within the field while produce is present? Domesticated animals in the production field are usually easy to exclude and control. To avoid the risk of animals contaminating products, they must not be permitted to enter fields and water sources during production.

In this case, if an animal defecates (poops) while in the field, there must be a plan in place to deal with it. It can be left in the field; however, a no-harvest buffer zone must be established around fecal contamination. If it is left in the field, rain splash can spread contamination. If a farmer decides to bury or remove the poop, it is essential to create sanitation procedures to make sure the right tools (such as gloves, shovels and buckets) are properly cleaned and sanitized afterward. Determine these arrangements ahead of time to improve produce safety.

There are many ways to address the risks of using working animals in the field, but practices should not result in more risks. Anyone who handles working animals must understand food safety risks that may be present and be trained to minimize them.

Pets on the Farm

Dogs and cats are ever-present on the family farm, and can, in some cases, be effective working animals, such as using cats for rodent control in packing houses. However, pets can present food safety hazards if they have access to fields and food packing areas; for example, cats can carry the parasite Toxoplasma gondii, which can cause severe illness in humans, including blindness, miscarriage and death, and should be kept away from food-packing facilities.

The Food Safety Modernization Act does not prohibit working dogs and cats on the farm, but their presence must be monitored and steps must be outlined to address their presence. Farmers with “u-pick” operations must instruct their customers not to bring their pets to the farm in order to prevent food safety risks and liability.


  • California Leafy Green Products Handler Marketing Agreement (LGMA). (2013) Assessing Animal Activity in the Field. 
  • CA LGMA Metrics August 2020 - Leafy Green Guidance
  • On-Farm Decision Tree Project: Wildlife and Animal Management—v3 07/16/2014 24 E.A. Bihn, M.A. Schermann, A.L. Wszelaki, G.L. Wall, and S.K. Amundson, 2014