Effective Salmonella control requires involvement of entire production chain

Since public interest drives public policy, it’s no surprise USDA’s Food Safety and Inspection Service (FSIS) tightened the standards for the maximum acceptable limit of Salmonella at processing.
calendar icon 16 August 2022
clock icon 8 minute read

Besides vaccination, proper ventilation and litter management to reduce litter moisture will help keep Salmonella numbers down during growout. So can drinking water acidification, which can reduce Salmonella levels in the crop. For at least the last 72 hours, water should be progressively acidified to the lowest pH that doesn’t affect water consumption.

Since broilers with a healthy intestinal tract are likely to carry less Salmonella,10 coccidiosis control is important. Composting or windrowing litter and avoidance of overcrowding are likewise useful. So is flock downtime — 18 days is acceptable, but if the contract allows, 21 days is better.

Feed withdrawal before processing needs to be just right. The goal is to reduce intestinal contents, but if birds get so hungry they start eating litter, they’re more likely to have Salmonella in their crops. The target withdrawal time is 8 hours. Intestinal strength diminishes with withdrawals of more than 10 hours.

Salmonella in feed

Speaking of feed, it’s best to consider all feed ingredients as Salmonella-contaminated, and even if they aren’t, they need to be protected from contamination. One important way to do that is by controlling dust when raw ingredients are delivered since dust can be a major source of Salmonella.

When heating feed for pelleting, the temperature needs to reach 185° F (85 °C). Be sure to avoid condensation in the pellet cooler. Formaldehyde and propionic acid can also be used to eliminate Salmonella in feed.

Feed mill equipment must be sanitised after cleaning. It’s imperative to have a robust pest-control program and tight biosecurity throughout the mill. Work shoes in particular can transfer Salmonella. Wild birds and, for that matter, all other animals need to be kept away from the mill and flocks.

Last chance: processing

As we all know, processing is our last chance to contain or eliminate Salmonella on chicken carcasses.

There should be a pre-scald carcass brush wash. It also helps to use acidic sanitisers on picker rails.

Scalders can be an intervention. If you use an acid sanitiser, you can decrease the scalder temperature to help maintain skin integrity, which reduces bacterial attachment and improves picking. The scalder temperature, however, shouldn’t go below 123° F (50.5° C), in which case Salmonella will grow. In addition, if you reduce fat liquefaction, and fat on equipment and in the chiller, you not only improve yield, you’ll have less Salmonella.

The evisceration process must ensure sanitary dressing. This might require reducing the line speed, adjusting equipment or making staff changes to prevent digestive-tract spillage and get the job properly done.

Producers have several options for chilling, including peroxyacetic acid (commonly called PAA), hypochlorus acid, which is chlorine, and buffered sulfuric acid. Organic and inorganic acids are also possibilities.

Post-chill, antimicrobial and/or acidified immersion baths should be used. Processing belts should be treated continuously with an antimicrobial such as chlorine, a stabilised acid or peroxyacetic acid.

When proper processing procedures are coupled with live-side efforts, they can go a long way toward reducing the prevalence of Salmonella on chicken carcasses.

Communication is essential

Based on my 29 years as a supervisory public health veterinarian, I can tell you that communication among everyone involved in poultry production is essential for good Salmonella control. Anecdotally, I can report that poultry companies with good management and communication among all facets of production have better results.

I recommend that live production managers attend FSIS meetings at least once monthly and review condemned carcasses along with processing plant management. Live production managers as well as service technicians and processing plant managers should collaborate on feed withdrawal to find what works best to prevent litter picking yet reduce intestinal contents.

There’s no doubt that a properly executed Salmonella prevention and control plan requires a lot of hard work and resources, but it’s not optional. It’s the cost of doing business. It prevents recalls, protects a producer’s brand and, in doing so, can save a lot of heartache and money.

Figure 1. Salmonella-positive rinses at rehang in conventional broilers vaccinated against Salmonella with a modified-live vaccine compared to unvaccinated controls
Figure 1. Salmonella-positive rinses at rehang in conventional broilers vaccinated against Salmonella with a modified-live vaccine compared to unvaccinated controls

© Poultry Health Today

In another trial involving 8.5 million broilers raised without antibiotics (4 million vaccinates), there was about a 30 percent reduction in positive carcasses and 40 percent reduction in parts positive for Salmonella (Figure 2).8,9

Figure 2. Salmonella-positive rinses at rehang and parts in broilers vaccinated against Salmonella with a modified-live vaccine and raised without antibiotics as compared to unvaccinated controls
Figure 2. Salmonella-positive rinses at rehang and parts in broilers vaccinated against Salmonella with a modified-live vaccine and raised without antibiotics as compared to unvaccinated controls

© Poultry Health Today

Besides vaccination, proper ventilation and litter management to reduce litter moisture will help keep Salmonella numbers down during growout. So can drinking water acidification, which can reduce Salmonella levels in the crop. For at least the last 72 hours, water should be progressively acidified to the lowest pH that doesn’t affect water consumption.

Since broilers with a healthy intestinal tract are likely to carry less Salmonella,10 coccidiosis control is important. Composting or windrowing litter and avoidance of overcrowding are likewise useful. So is flock downtime — 18 days is acceptable, but if the contract allows, 21 days is better.

Feed withdrawal before processing needs to be just right. The goal is to reduce intestinal contents, but if birds get so hungry they start eating litter, they’re more likely to have Salmonella in their crops. The target withdrawal time is 8 hours. Intestinal strength diminishes with withdrawals of more than 10 hours.

Salmonella in feed

Speaking of feed, it’s best to consider all feed ingredients as Salmonella-contaminated, and even if they aren’t, they need to be protected from contamination. One important way to do that is by controlling dust when raw ingredients are delivered since dust can be a major source of Salmonella.

When heating feed for pelleting, the temperature needs to reach 185° F (85 °C). Be sure to avoid condensation in the pellet cooler. Formaldehyde and propionic acid can also be used to eliminate Salmonella in feed.

Feed mill equipment must be sanitised after cleaning. It’s imperative to have a robust pest-control program and tight biosecurity throughout the mill. Work shoes in particular can transfer Salmonella. Wild birds and, for that matter, all other animals need to be kept away from the mill and flocks.

Last chance: processing

As we all know, processing is our last chance to contain or eliminate Salmonella on chicken carcasses.

There should be a pre-scald carcass brush wash. It also helps to use acidic sanitisers on picker rails.

Scalders can be an intervention. If you use an acid sanitiser, you can decrease the scalder temperature to help maintain skin integrity, which reduces bacterial attachment and improves picking. The scalder temperature, however, shouldn’t go below 123° F (50.5° C), in which case Salmonella will grow. In addition, if you reduce fat liquefaction, and fat on equipment and in the chiller, you not only improve yield, you’ll have less Salmonella.

The evisceration process must ensure sanitary dressing. This might require reducing the line speed, adjusting equipment or making staff changes to prevent digestive-tract spillage and get the job properly done.

Producers have several options for chilling, including peroxyacetic acid (commonly called PAA), hypochlorus acid, which is chlorine, and buffered sulfuric acid. Organic and inorganic acids are also possibilities.

Post-chill, antimicrobial and/or acidified immersion baths should be used. Processing belts should be treated continuously with an antimicrobial such as chlorine, a stabilised acid or peroxyacetic acid.

When proper processing procedures are coupled with live-side efforts, they can go a long way toward reducing the prevalence of Salmonella on chicken carcasses.

Communication is essential

Based on my 29 years as a supervisory public health veterinarian, I can tell you that communication among everyone involved in poultry production is essential for good Salmonella control. Anecdotally, I can report that poultry companies with good management and communication among all facets of production have better results.

I recommend that live production managers attend FSIS meetings at least once monthly and review condemned carcasses along with processing plant management. Live production managers as well as service technicians and processing plant managers should collaborate on feed withdrawal to find what works best to prevent litter picking yet reduce intestinal contents.

There’s no doubt that a properly executed Salmonella prevention and control plan requires a lot of hard work and resources, but it’s not optional. It’s the cost of doing business. It prevents recalls, protects a producer’s brand and, in doing so, can save a lot of heartache and money.

Poultry Health Today

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