Identifying pre-harvest Salmonella is essential for poultry producers to protect flock health and economic viability. Outbreaks are costly—2020 national estimates placed the annual burden at $2.8 billion.1
Salmonella contamination can also lead to processor rejections to meet USDA performance standards. A University of Georgia field report notes that if 23.5% or more of carcass samples in an FSIS set test positive, the plant fails inspection.2 Three consecutive failures can result in USDA withdrawing inspection, halting production, and creating significant financial and reputational risks.
To combat the risk of Salmonella contamination, protect flocks and preserve business relationships, pre-harvest intervention methods are integral. Producers have a responsibility to adopt proactive measures to meet USDA standards while safeguarding public trust and processor relationships.3
Common indicators of pre-harvest Salmonella
The majority of poultry carry Salmonella asymptomatically, and the presence of the pathogen does not often present in flock level changes.4 Most infections show no obvious signs, but some flock-level changes may indicate risk, including lethargy, loss of appetite and diarrhea.5 Diarrhea can spread the pathogen through litter, contaminating the environment.
Environmental indicators, especially darkling beetles, can also signal Salmonella risk. Darling beetles are a reliable indicator of Salmonella transmission in poultry houses as they are proven carriers of several pathogens, including Salmonella. These pests thrive in dark areas, burrow in litter and contaminate feed and water, making pest control essential for reducing pre-harvest transmission.
Diagnostic and testing strategies
Once risk indicators are identified, diagnostic testing confirms infection and guides interventions. Producers can use destructive sampling, collecting internal tissues like ceca, liver or spleen, or non-destructive sampling with boot socks, cloacal swabs or hatchery chick trays for ongoing monitoring without losing birds.
Laboratory testing options:
- Culture-based methods: Non-invasive sampling from drag swabs or boot socks. Samples are incubated in selective broths and monitored for Salmonella growth.
- DNA-based rapid assays: Polymerase chain reaction (PCR) and quantitative PCR (qPCR) detect Salmonella within hours, providing presence and load data.
Protecting economic viability
Salmonella is one of the most persistent challenges facing poultry operations. Pre-harvest monitoring helps protect producers, processors and over-all flock health.
Subtle flock signs and environmental indicators, combined with timely diagnostic testing, can allow producers to intervene early, reducing pathogen spread and safeguarding the long-term sustainability of poultry operations.
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© 2026 Elanco or its affiliates.
Francene Van Sambeek, D.V.M, MAM, ACPV Poultry Technical Consultant
Dr. Francene Van Sambeek is a graduate of Michigan State University. Her areas of expertise include broiler and broiler-breeder Intestinal Integrity, vaccines and animal welfare.
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1 Scharff, R. 2020. “Food Attribution and Economic Cost Estimates for Meat- and Poultry-Related Illnesses.” In: “Journal of Food Protection.” International Association for Food Protection. https://www.sciencedirect.com/science/article/pii/S0362028X22103248
2 Ritz, C. 2024. “Troubleshooting Salmonella in Poultry Processing Plants: Case Studies.” University of Georgia College of Agriculture and Environmental Sciences. UGA Extension Publications. https://fieldreport.caes.uga.edu/publications/B1310/troubleshooting-salmonella-in-poultry-processing-plants-case-studies/
3 “Salmonella Framework for Raw Poultry Products.” August. 2024. Food Safety and Inspection Service. Accessed 9/3/25. https://www.fsis.usda.gov/policy/federal-register-rulemaking/federal-register-rules/salmonella-framework-raw-poultry-products
4 Edrington, T. S., & Brown, T. R. (2022). A Commentary on Salmonella From a Pre-Harvest Perspective. Frontiers in Animal Science, 3, 877392. https://doi.org/10.3389/fanim.2022.877392
5 Din, T., Khan, W., et al. 2025. “Salmonellosis in Poultry: A Clinical Perspective.” In: “Diseases Across Life: From Humans to Land and Sea.” Unique Scientific Publishers. https://www.researchgate.net/publication/393097032_Salmonellosis_in_Poultry_A_Clinical_Perspective
