# Wild Birds Pose Unique Food Safety Threats in the US Southeast

## TL;DR

Wild birds in the US Southeast may pose food safety risks by spreading Salmonella on produce, especially in areas with livestock and wetlands.

## Contribution

This study identifies Salmonella in bird feces on produce farms in the Southeast and links its presence to livestock and wetland landscapes.

## Key findings

- Salmonella was detected in 8.6% of bird fecal samples collected from produce fields.
- Salmonella prevalence was highest in areas with livestock and abundant wetlands.
- Campylobacter was not detected in any bird fecal samples collected from crops.

## Abstract

Wild birds may endanger food safety when they defecate onto fresh produce. These risks have been primarily studied in the western US, where Campylobacter is the most common bacterial foodborne pathogen associated with birds, and pathogen prevalence increases in bird feces in crop fields near cattle production. To understand the food safety risks posed by birds in the US Southeast, we collected bird feces from produce fields and tested them for the presence of Salmonella and Campylobacter. Campylobacter was never detected in bird feces on crop plants, while Salmonella detection (in 8.6% of fecal samples) was most common on farms within landscapes with abundant wetlands that also had livestock. Birds may pose different food safety risks in the Southeast than elsewhere.

Natural areas near farmland can provide refuge for birds that contribute to natural pest control. However, birds can endanger food safety by defecating on or near produce. Work in the western US suggests that Campylobacter spp. are the potential foodborne pathogens most commonly associated with wild birds and that pathogen prevalence is higher in landscapes dominated by animal agriculture. However, relatively little is known about other fresh-market-produce growing regions. Working on produce farms in the Southeastern US, we characterized bird communities, tested bird feces deposited on crop foliage for Campylobacter and Salmonella, and searched for landscape features associated with heightened bird-associated food safety risks. We found that bird communities on farms were generally similar across ecoregions. Campylobacter was never detected from bird feces deposited on crop foliage, but Salmonella was detected in 8.6% of fecal samples. Salmonella prevalence in crop-surface-collected bird feces was highest when farms also produced livestock and when wetland cover was prevalent in the landscape. Overall, our results suggest that on-farm livestock production may be an indicator of bird-associated food safety risks in the Southeast, as in the West. We suggest there may be some similarities, but important differences, in food safety risks posed by birds in different US produce growing regions.