Campylobacter coli in Swine Slaughtering Flowchart and Research of cdt Genes

Abstract

Background: Campylobacter spp. are among the microorganisms most commonly associated with foodborne disease. Campylobacter spp. isolation from pigs during the slaughter and final products have been reported in several countries, including Brazil. However, very little is known about the sources of contamination in the slaughtering flowchart and how these microorganisms are spread in processing plants. Considering the possibility of the pigs carry Campylobacter spp. since the farm or its products are contaminated in the slaughterhouse, this study had as aim to track Campylobacter spp. in pig slaughtering flowchart to understand the behavior of these pathogens in the production line.Materials, Methods & Results: Forty animals of 10 lots, four from each lot, were followed during slaughter. Stool samples were collected from the floor of each enclosure where the pigs were housed on the farm and immediately after stunning on slaughterhouse. Samples from carcass surface were collected after removal of the animals from scrap machine, after evisceration and before the refrigeration chamber. It was also collected surface samples from jowls and samples from the scalding tank water before and after the passage of animals. The swabs containing samples were plated onto Columbia agar supplemented with activated charcoal, oxygen reduction solution and antibiotics supplement, and incubated at 42°C for 48 h under microaerobic conditions. The colonies which presented with a shiny and moist appearance were analyzed by Gram staining for identification of Campylobacter by morphology, and then tested for catalase and oxidase. The Campylobacter isolates were identified for species C. jejuni or C. coli by PCR. Bands profiles were determined by rep-PCR and used to compare the strains. Campylobacter was isolated from 19 (9.5%) of the 200 pig samples analyzed, seven (36.8%) of the rectum, seven (36.8%) after evisceration and five (26.3%) before the refrigeration chamber. Campylobacter was not isolated from jowls and from scalding tank water. All isolates were C. coliand cdtnegative.Persistence of strains originating from the farm and cross contaminations during the slaughtering flowchart was identified by the analysis of the bands profiles obtained by rep-PCR.Discussion: C. coli was the species of Campylobacter present in the swine intestinal tract and in the swine slaughterhouse. The animals, once contaminated, can carry the microorganism during the stages of the slaughtering flowchart. The farm where the animals came from is an important source of contamination during processing, however cross contamination also plays a relevant role. The evisceration was considered the most critical stage, due to the greater number of isolates obtained after this procedure, what emphasize the importance of the hygienic-sanitary management in this stage. Campylobacter spp. can survive, despite not being able to multiply, in foods at refrigeration temperatures (-1 to 5°C) for one to three weeks. Therefore, the high percentage of isolates obtained from the carcass before the refrigeration chamber may represent a problem, since the contamination of the carcasses that enter in this sector can be maintained until the food reaches the consumer. There was no similarity between strains isolated from different lots, indicating that there were no persistence of strains both in the farm and in the slaughterhouse.

Prevalence, Population Diversity and Antimicrobial Resistance of Campylobacter coli Isolated in Italian Swine at Slaughterhouse

“…A co-infection with C. jejuni has only been observed in three animals. This is in agreement with a previous report from Italy, showing low levels of C. jejuni colonization in pigs [29]. The higher prevalence of Campylobacter in carcasses compared to faeces could indicate a cross contamination during the slaughter process, argued by the low level of contamination and also confirmed by PFGE analysis.…”

“…The higher percentage of positive faeces recorded during the warm seasons are consistent with the Campylobacter seasonality reported in pig [30]. C. coli is often present in the intestinal tracts of swine, and carcasses may be contaminated during evisceration, which is considered the most critical phase of slaughter, with possible cross-contamination between carcasses, if they have the possibility to be in contact along the slaughtering line or the equipment used for evisceration is not properly cleaned and disinfected between carcasses [29]. However, contamination levels are significantly reduced by the chilling of the carcasses [31] and Campylobacter is found only at low levels in pork retail products [32][33][34].…”

“…Despite not be able to grow out of the body of the living host, Campylobacter can survive in food products at refrigeration temperatures from one to three weeks. This clearly indicates the importance of the contamination of carcasses (and therefore of the meats), given the capacity of Campylobacter to survive after refrigeration and the following processing phases, and determining infections in the consumers [29]. Each farm from which the tested pigs originated resulted as characterized by different clonal populations, characterized by several STs.…”