Reducing Campylobacter contamination during defeathering

Organic acids can help reduce the incidence of Campylobacter on broiler carcasses.

Campylobacter is associated with poultry and poultry meat products and is frequently isolated from live broilers. Gut contents of a Campylobacter positive broiler can contain more than a million cells of Campylobacter per gram. 

Overall, poultry processing lowers bacterial contamination of carcasses. However, as carcasses pass through a commercial feather-picking machine, picker fingers press on the abdomen and force gut contents out of the cloaca. We have shown that this causes the number of Campylobacter recovered from broiler carcass skin to increase significantly during feather removal. 

Controlling Campylobacter

Controlling the increase in Campylobacter contamination during feather removal could help processors produce finished products with fewer Campylobacter thereby lessening risk of foodborne illness to the consumer.

The objective of this study was to test the effect of three different organic acids placed in the cloaca before scalding on the numbers of Campylobacter found on the broiler carcass breast skin after automated defeathering.

One molar concentrations of acetic acid (pH 2.3), lactic acid (pH 1.9) and proprionic acid (pH 2.4) were tested for their ability to reduce the number of Campylobacter on carcasses.

Experimental methodology

In each of three replicate trials, 10 carcasses were treated with each acid and another 10 were treated with sterile water as a control. Live, 42-day-old broilers were obtained from a commercial processing plant after approximately 12 hours of feed withdrawal. Broilers were caged in plastic coops and transported to a pilot processing facility. Broilers were electrically stunned and killed using commercial processing equipment. 

Following bleed out, each carcass was subjected to a manual abdominal squeeze to express contents from the cloaca. Then the test liquid was injected into the cloaca using a sterile pipette. Each pipette was gently inserted until resistance was met, at approximately 3 centimeters, and 12 milliliters of acid or water was pumped into the cloaca. Upon removal of the pipette, the vent was held shut for three seconds to minimize leakage of the liquid. 

Following treatment, carcasses were scalded in a set of three triple-pass scald tanks with a water temperature of 56° Celsius (132.8° Fahrenheit) and then proceeded into a commercial defeathering machine.

The breast skin of each carcass was sampled before and after feather removal to determine numbers of Campylobacter present. Carcasses were sampled using a sterile sponge pre-moistened with 10 ml of sterile phosphate buffered saline (PBS). 

Each carcass was sampled by three downward swipes on the breast skin between feather tracts from the tip of the keel to the top of the breast. An additional 10ml of PBS was then added to each sponge prior to stomaching for 30 seconds. Next, serial dilutions of diluent were made in PBS and plated on Campy-Cefex agar. Plates were then incubated in a microaerobic atmosphere at 42°C (107.6° F) for 48 hours and colonies characteristic of Campylobacter were counted. 

Each colony type from every sample was confirmed as Campylobacter by observation of typical cellular morphology and motility on a wet mount under a phase-contrast microscope and further confirmed by utilizing a serological latex agglutination test.

Birds treated with organic acid had close to 99% fewer Campylobacter detected than the control group.

Results

In every case, numbers of Campylobacter on breast skin increased during feather picking as expected. Water treated carcasses had an increase of 3.5 log units. All three acid treatments resulted in significantly less breast skin contamination by Campylobacter than the water treated control. Treated carcasses had close to 99% fewer Campylobacter than water treated control carcasses.  

Conclusion

Practical use of this type of treatment in a commercial setting would require an engineering solution for application. Assuming that the mechanical logistics are solved, such a treatment would be expected to result in lower Campylobacter numbers being on the skin prior to the use of an inside-outside washer and other interventions commonly used in poultry processing. 

Sources available upon request.

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