Interpretive Summary: What are the sources of Salmonella on poultry farms before processing?
By Deepak Subedi
Researchers at the University of Georgia set out to answer a simple but important question: Where is Salmonella coming from on poultry farms before birds even reach the processing plant? To find out, they reviewed and analyzed decades of research to pinpoint the biggest sources of these bacteria during broiler production.
The goal of the study was to figure out which parts of the poultry production process are most likely to introduce or spread Salmonella, whether it’s the hatchery, the litter, the feed, or even the drinking water. Knowing this helps producers focus their efforts and resources where it matters most to keep poultry meat safer.
To do this, the team reviewed over 16,000 studies and included 39 detailed research papers from different parts of the world including the United States. They grouped the data by sources of Salmonella and calculated how often the bacteria was found in each of those areas using statistical models.
So, what did they find?
The hatchery came out as the top source, with Salmonella showing up in nearly half of the samples (48.5%). That means the process of hatching chicks, from eggshells to fluff and surfaces inside the hatcher, is a major risk point. Once Salmonella gets into the hatchery, it can easily reach the chicks and stay with them throughout their life.
Next was poultry litter, where the bacteria were found in about 1 out of every 4 samples (25.4%). This makes sense because litter is often reused and mixed with feces from the birds. If it’s not managed well, it becomes a perfect environment for bacteria to thrive and spread.
Feces themselves, the droppings birds leave behind, were also a major contributor at 16.3%. Birds that carry Salmonella can pass it on to others through their droppings, which then contaminate the litter, floors, and even other birds.
Other sources had lower but still noteworthy risks:
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Interior of the poultry house (walls, fans, pests like rodents and beetles): 7.9%
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Feed: 4.8%
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Chicks (direct from hatcheries): 4.7%
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Poultry house exterior (soil, puddles, wild birds): 4.7%
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Drinking water: 2.0%
Why does this matter for producers?
This study highlights that controlling Salmonella before birds go to the processing plant is crucial. While many farms focus on interventions during processing, a big part of the problem starts earlier. For example, improving hygiene in hatcheries, managing and treating litter between flocks, and keeping pests under control inside poultry houses can make a big difference.
Even though drinking water and feed showed lower contamination rates, they’re still important. Bacteria in the water lines or feed bins can silently spread through the flock if left unchecked.
What can the industry do?
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Focus on hatchery hygiene: Clean and sanitize hatching equipment thoroughly and control dust and fluff buildup.
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Manage litter better: Consider treatments between flocks to reduce bacterial load.
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Monitor pests: Rodents and beetles are known to carry Salmonella, so pest control is essential.
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Check feed sources: Keep feed bins clean and monitor for contamination.
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Don’t forget the outside: Wild birds and nearby animals can bring in pathogens, so biosecurity at the farm gate matters.
What's next?
The researchers suggest more work is needed on preharvest interventions like vaccines, feed additives, and better hatchery design to keep Salmonella under control before it ever reaches the processing stage.
This study was published in the journal Poultry Science, Volume 102, Issue 5, May 2023, Article 102566, and can be found online here: https://doi.org/10.1016/j.psj.2023.102566