Effect of morphological changes in feather follicles of chicken carcasses after defeathering and chilling on the degree of skin contamination by <i>Campylobacter</i> species

Abstract

Campylobacter jejuni and C. coli are the leading causes of enteric infections in many developed countries. Healthy chickens are considered to act as reservoirs of campylobacters, as the organisms colonize the intestinal tract. Once infected birds enter a processing plant, contamination of chicken carcasses with campylobacters occurs over the entire skin during defeathering and evisceration due to leakage of crop and/or intestinal contents. Although the role of feather follicles in the contamination of chicken carcasses by campylobacters during processing is still debatable, it has been considered that the microorganisms would be entrapped and retained in the follicles due to the morphological changes resulting from defeathering and chilling. In the present study, we observed the morphology of feather follicles in chicken carcasses after defeathering and chilling. A total of 3,133 feather follicles were examined for morphological changes before and after chilling. Shortly after defeathering, most (91.5%) of the follicles were closed, whereas after chilling they were either closed (85.5%) or open (6%), although a small proportion of enlarged follicles became smaller or closed (2.6%). Moreover, 5.9% of the follicles that were slightly open became further enlarged after chilling. Furthermore, the proportion of enlarged feather follicles that became closed after chilling showed no discernible relationship with the degree of campylobacter contamination in different areas of the carcass skin, suggesting that campylobacters may not be confined to feather follicles as a result of the morphological changes attributable to defeathering and chilling.

Complex Internal Microstructure of Feather Follicles on Chicken Skin Promotes the Bacterial Cross-Contamination of Carcasses During the Slaughtering Process

“…Latt et al (2018) found that 85% of the feather follicles of slaughtered broiler chickens were closed, and 6% were open after chilling. Furthermore, the proportion of enlarged feather follicles has no discernible relationship to the degree of Campylobacter jejuni contamination in different areas of the carcass skin (Latt et al, 2018). Based on the analysis of the microstructural changes of chicken skin feather follicles and the changes of the bacteria composition inside the feather follicles above, it is believed that the feather follicle structure inside the chicken skin plays a important role of containing bacterial contamination during the slaughter process, which is not conducive to the cleaning and decontamination of bacteria of chicken carcasses in the slaughter process.…”

“…This process sealed the follicle cavity of the follicles, promoting the resistance of the bacteria to disinfectants and cleaning. The paraffin sections of the different stages ( Figure 1 ) indicate that a percentage of the follicles shrunk and closed the entrances with a fatty layer of skin due to post-mortem rigidity, which is a normal phenomenon in dead animal tissues ( Barbut, 2015 ; Latt et al, 2018 ). These organic-rich tissue fluids in the follicles also provide protection for the absorbed bacteria against disinfection by consuming the disinfectant because feather plucking can injure the follicle’s primary tissue, allowing the tissue fluid to ooze out.…”

“…Many studies have documented the location of contamination bacteria on the surface microstructure of chicken skin as well as bacterial cross-contamination during slaughter (Cason et al, 2004;Chantarapanont et al, 2004;Jang et al, 2007;Latt et al, 2018). Jang et al (2007) find that the adsorption sites of Campylobacter jejuni are located on the skin surface and in the follicles.…”

“…However, fresh chicken is susceptible to spoilage-related microbial group contamination, such as ephemeral/specific spoilage organisms (E/SSO), destroying the shelf life of products and resulting in massive economic losses ( Doulgeraki et al, 2012 ; Wang et al, 2017 ). Furthermore, it is generally believed that the complex structure of chicken skin tissue makes it more susceptible to bacterial contamination because it is difficult to clean and reduce bacteria during slaughter ( Berndtson et al, 1992 ; Yang et al, 2001 ; Cason et al, 2004 ; Jang et al, 2007 ; Latt et al, 2018 ).…”

Current Status of <i>Campylobacter</i> Food Poisoning in Japan

“…A previous study has demonstrated that microorganisms would be entrapped and retained in the feather follicles 38,61) due to morphological changes resulting from defeathering and chilling 62) . However, the proportion of enlarged follicles that became closed after chilling showed no discernible relationship with the degree of Campylobacter contamination in different areas of the carcass skin, suggesting that campylobacters may not be confined to feather follicles as a result of the morphological changes attributable to defeathering and chilling 63) .…”