Passage through automated feather picking machines used in poultry processing can increase the number of Campylobacter bacteria on carcasses by 100 times. This is problematic because carcasses can carry high numbers of Campylobacter into the rest of the plant, making it harder to keep the level of the pathogen on post-chill carcasses as low as possible.
Potential sources of Campylobacter in picking
There are several factors that could be contributing to the Campylobacter increase during picking:
- Transfer of built-up surface contamination from the picking machine to carcasses.
- Airborne transfer of Campylobacter from highly contaminated carcasses to others.
- Expression and spread of Campylobacter contaminated cloacal contents during the process.
Separate research studies were designed and conducted to evaluate each of these possibilities.
Contamination from the machines?
One study was conducted to determine if contact with surfaces in naturally contaminated picking machines contributes to the increased Campylobacter counts. Fully-processed, chilled carcasses with low numbers of Campylobacter were used to examine the effect of the machine’s surface contamination on Campylobacter numbers. Chilled carcasses were hung on shackles and allowed to proceed through three, sequential empty machines during a processing break in a commercial slaughter plant. The machines were previously soiled by about 20,000 broilers.
Standard, feathered control carcasses underwent the expected large increase in Campylobacter numbers associated with picking. However, Campylobacter numbers on chilled carcasses did not increase while passing through the same machines. This suggests naturally contaminated surfaces of the machines are not a primary cause of the increase in Campylobacter.
Campylobacter is a leading cause of foodborne illness and processors are always looking to reduce the presence of the bacteria. | US Poultry & Egg Association
Contamination from the air?
Another study investigated the contribution of airborne contamination. Mechanical picking creates mist and causes particles of dust, feathers, feces and other matter to become airborne around the machine. According to air quality studies, air in the picker room generally is more heavily contaminated than any other area in the processing plant.
In this study, chilled carcasses with low numbers of Campylobacter were suspended at several points near an operating commercial feather picker and exposed to airborne contaminants for one minute. Bacteria, including Campylobacter, were detected in the air near the picker. However, microbiological culture of carcasses after exposure to airborne contamination in the picker room revealed that they had no more Campylobacter than unexposed carcasses.
Contamination from the cloaca?
Spinning rubber fingers in a commercial feather picker press on the abdomen and can force small amounts of cloacal contents out of broiler carcasses. Gut contents of colonized broilers can carry high numbers of Campylobacter bacteria.
We examined the influence of leaking gut contents on carcass Campylobacter numbers. In this study, Campylobacter-positive broilers obtained at a commercial processing plant and transported live to our pilot plant were divided into two groups. In the first group, just prior to scalding, the cloacae were plugged with absorbent cotton tampons and sutured shut. The second was used as the control group.
Carcasses were scalded and breast skin was sampled before and after picking. Breast skin contamination on plugged carcasses was compared to that on unplugged control carcasses from the same flock. After passing through the picker, 100 percent of control carcasses had Campylobacter-positive breast skin samples with an average contamination level of 15,849 colony forming units per 30 square centimeters of skin, while only 10.8 percent of the plugged carcasses had detectable levels on the breast skin with an average of contamination level of 316 colony forming units per 30 square centimeters of skin.
Conclusions
The studies indicate the increase in broiler carcass Campylobacter numbers during picking is largely due to the escape of contaminated feces from the cloaca. A small, barely visible spot of gut contents can spread the bacteria. A later study demonstrated that as little as 5 milligrams of cecal contents can cause a significant increase in the numbers of Campylobacter on eviscerated broiler carcasses. In our next paper on this topic, we will detail several studies in which intervention strategies targeting this very important situation were developed and tested.
Read more:
Salmonella, Campylobacter infection routes in broilers, www.wattagnet.com/articles/34510
