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Remember to scout for scat prior to harvest

Every (garden) party has a pooper, and as growers we all know that keeping animals out of the garden can be incredibly challenging! No matter what we do, there’s always something that seems to find its way to our crops, whether it be birds, raccoons, rabbits, deer, or even a bear.

And it’s not just plant damage that we need to be concerned about; animals can carry human pathogens (bacteria, viruses, and parasites) in their feces and they can spread that contamination around fields as they move.

Bird droppings on blueberries. Photo: Anne Sawyer

Eating raw produce that has been contaminated can make us very sick. Just this past summer, an outbreak of E. coli O157:H7 was traced to romaine lettuce grown near Yuma, Arizona. The source of contamination is believed to be a nearby cattle feedlot. In total, 210 people were sickened and five people died, including two deaths in Minnesota.

Symptoms of foodborne illness generally involve diarrhea, abdominal cramps, nausea and/or vomiting, and can also include fever, fatigue, muscle aches, and more. Children, older people, those who are pregnant or those who have weakened immune symptoms can be at even greater risk of severe illness or even death from foodborne pathogens. Therefore, we want to be sure that we do all we can to minimize the risk of contamination in fresh produce.

Can I just wash it off?

Unfortunately, no. Once produce is contaminated with feces, that contamination can be nearly impossible to remove. Crops such as strawberries or cantaloupes have a rough surface texture where pathogens can reside. Leafy greens have a large surface area and folds or wrinkles that may be difficult to thoroughly wash. Stem scars, cracks, punctures or other injuries also provide great hiding places for pathogens. Many microorganisms secrete glue-like carbohydrates that help them cling to the surface of produce, making it even more difficult to completely remove.


Cantaloupe netting can harbor pathogens. Photo: Produce Safety Alliance.

Sometimes feces can be difficult to see, such as in the above picture of blueberries, and you realize too late that you’ve picked something with poop on it. If you accidentally touch something that’s been contaminated, stop what you’re doing and go wash your hands with soap and water before returning to harvest.

If you accidentally put something with feces into the harvest bucket, be aware that you may have spread contamination to the rest of your harvest bucket. Any produce that may be contaminated should not be consumed raw.

Awareness is key

One way to minimize risk of accidental contamination is by completing a preharvest assessment prior to picking. Examine the ground and plants for signs of animal intrusion. Both wind and rain can transmit particles and pathogens from feces to nearby produce, so do not harvest any produce for raw consumption that is near feces.

It’s up to you to determine the size of the area not to harvest when feces is found. Consider the risk based on the type of crop as well as the size and amount of poop. Crops growing near or in contact with the ground, such as strawberries or leafy greens, may be at greater risk from rainsplash than trellised tomatoes, and a cow pie has greater potential for contamination spread than mouse droppings. In general, it’s wise to avoid harvesting anything that’s close to visible feces – better safe than sorry!

If feces is found, consider marking the area in order to avoid an accidental harvest of contaminated produce. After you’ve finished harvesting, you can go back and remove the feces. Be sure that any tools you use to remove it are NOT used for production or harvest related activities later on, unless they are properly cleaned and sanitized.

Fox scat near young lettuce. Photo: Anne Sawyer

Animal activity monitoring

If your farm is covered under the Food Safety Modernization Act (FSMA) Produce Safety Rule (PSR), §112.112 requires a visual assessment of the growing area and all covered produce.

Specifically, it requires that those covered by the rule take all measures reasonably necessary to identify, and not harvest, covered produce that is reasonably likely to be contaminated with a known or reasonably foreseeable hazard. Although the Produce Safety Rule does not require growers to keep a written record of those assessments, most third-party food safety audits do.

To learn more about whether your farm is covered by the Produce Safety Rule, see this factsheet: FSMA and the Produce Safety Rule: does the rule apply to me?

Regardless, all growers should consider keeping a record of their preharvest assessments. Tracking animal activity, both at harvest and throughout the year, allows you to assess your practices for effectiveness, recognize patterns in animal activity, and revise your exclusion efforts accordingly. You’ll not only save time and money, but you just might save your customers, too!

For more information:

To learn more about and register for upcoming FSMA Grower Training Workshops: Click here

The University of Minnesota Extension On-Farm Good Agricultural Practices (GAPs) Education Program team can help you understand GAPs and FSMA, farm food safety principles and help you prepare for a GAP audit. Reach us at safety@umn.edu or visit http://safety.cfans.umn.edu/.

FDA page on the FSMA Produce Safety Rule: Click here.

Minnesota Department of Agriculture Produce Safety Program: Click here.

The Internet Center for Wildlife Damage Management provides research-based information regarding animal exclusion: http://icwdm.com/.

Author: Anne Sawyer, Extension Educator - On-Farm Food Safety
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