Monitoring of microbial hazards at farms, slaughterhouses, and processing lines of swine in Korea

Sock and Environmental Swabs as an Efficient, Non-Invasive Tool to Assess the Salmonella Status of Sow Farms

Salmonellosis is the second most reported gastrointestinal infection in humans after campylobacteriosis and a common cause of foodborne outbreaks in the European Union (EU). In addition to consumption of contaminated animal-based foods, such as poultry, beef and eggs, pork is an important source of human salmonellosis outbreaks; therefore, Salmonella (S.) control should start in the early stages of pig production. To be able to implement effective control measures to reduce the risk of pigs being infected by Salmonella, it is important to identify the serovars circulating on farm within the different stages of production, including as early as sow and piglet breeding. The aim of the present study was to assess the Salmonella status of sow farms either producing their own finishers or delivering piglets to fattening farms with a known high serological prevalence identified within the QS Salmonella monitoring system. Overall, 97 (92.4%) of 105 investigated piglet-producing farms across Germany tested positive in at least one sample. Salmonella was detected in 38.2% of the sock and 27.1% of the environmental swab samples. S. Typhimurium was the most frequent serovar. In conclusion, sock and environmental swab samples are well suited for non-invasive Salmonella detection in different production units in farrowing farms. To establish a holistic Salmonella control program, all age classes of pig production should be sampled to enable intervention and implementation of countermeasures at an early stage if necessary.

Distribution and tracking of Clostridium difficile and Clostridium perfringens in a free-range pig abattoir and processing plant

The presence and genetic diversity of Clostridium difficile and C. perfringens along the slaughtering process of pigs reared in a free-range system was assessed. A total of 270 samples from trucks, lairage, slaughter line and quartering were analyzed, and recovered isolates were toxinotyped and genotyped. C. difficile and C. perfringens were retrieved from 14.4% and 12.6% of samples, respectively. The highest percentage of positive samples for C. difficile was detected in trucks (80%) whereas C. perfringens was more prevalent in cecal and colonic samples obtained in the slaughter line (85% and 45%, respectively). C. difficile isolates (n = 105) were classified into 17 PCR ribotypes (including 010, 078, and 126) and 95 AFLP genotypes. C. perfringens isolates (n = 85) belonged to toxinotypes A (94.1%) and C (5.9%) and were classified into 80 AFLP genotypes. The same genotypes of C. difficile and C. perfringens were isolated from different pigs and occasionally from environmental samples, suggesting a risk of contaminated meat products.

Bacterial Quality and Prevalence of Foodborne Pathogens in Edible Offal from Slaughterhouses in Korea

Edible offal meats have recently received significant attention worldwide. However, studies evaluating the microbial quality of diverse edible offal and specifically investigating contamination by pathogens that cause foodborne illnesses are rare. Our study was conducted to investigate the microbiological quality of six kinds of edible offal produced from 11 pigs and 8 cattle slaughterhouses in the Republic of Korea and the prevalence of pathogenic microorganisms such as Salmonella, Clostridium perfringens, Staphylococcus aureus, and Escherichia coli O157:H7 in these products. The values for aerobic plate counts, coliform counts, and E. coli counts in red offal were 1.00 to 6.70, 0 (below 10 CFU) to 4.78, and 0 to 4.00 log CFU/g, respectively. For green offal, the values were 3.00 to 7.00, 1.48 to 6.30, and 0 to 6.00 log CFU/g, respectively. The most frequently detected foodborne pathogen was Salmonella (23.8% prevalence in pig offal and 7.1% prevalence in cattle offal), followed by C. perfringens (11.1 and 7.1%, respectively) and S. aureus (12.7 and 2.4%, respectively). None of the offal samples tested positive for E. coli O157:H7. Considering the microbial quality of offal from Korean slaughterhouses and the prevalence of foodborne pathogens in this material, more refined hygienic standards such as a hazard analysis critical control point system for processing, packing, and transporting edible offal are necessary for preventing further contamination.

Changes in microbial contamination levels of porcine carcasses and fresh pork in slaughterhouses, processing lines, retail outlets, and local markets by commercial distribution

The objective of this study was to evaluate the changes in microbial contamination levels of each porcine carcass and fresh pork in a general distribution process. A total of 100 commercial pigs were sampled (six sampling sites per individual, total 600 samples) at four sequential stages: slaughterhouse (after carcass grading and boning), processing line, retail outlet, and local market. No significant differences were observed in the contaminant percentages among sampling sites and sample collection years (P>0.05) with the exception of Bacillus cereus. The contaminant percentage of B. cereus at 1st collection year was higher than these of 2nd collection year (28.31% vs. 12.26%, P<0.05). B. cereus and Listeria monocytogenes were the most frequently detected pathogenic bacteria in the slaughterhouse and markets, respectively. On the other hand, Escherichia coli O157:H7 and Yersinia enterocolitica were not detected in carcasses or pork collected from any carcass sites and pork samples. However, the frequency of pathogenic bacteria in end-products at local markets was not highly related to the initial contamination of porcine carcasses in the slaughterhouse. Thus, the improvement of microbial safety for pork end-products requires hygienic control of porcine carcasses and meat cutting during all operations in the slaughterhouse, processing line, retail outlet, and local market.

Aerobic plate counts as a measure of hazard analysis critical control point effectiveness in a pork processing plant

A hazard analysis critical control point (HACCP) system was designed to identify specific hazards so that preventive and control measures to ensure the safety of a food could be implemented. Microbiological data generated through sampling were used to characterize the hygienic performance and to validate and verify the various HACCP plans. Aerobic plate counts (APCs) often are chosen as an indicator of the effectiveness of HACCP plans, because data for all aerobic bacteria are more easily collected than are data for pathogens of concern or other indicator organisms. However, it is not clear whether APCs are useful in verifying that a HACCP plan is working satisfactorily. In this study, APC data were collected from one pork-cutting plant in Korea both before and after the company initiated its HACCP plan. These APC data were used to compare microbiological differences and to determine the effect of any changes before and after implementing the HACCP plan. For this pork plant, after the HACCP plan was implemented the proportion of samples exceeding the 3 log CFU/cm2 limit dropped from 73.39 to 4.29% for the overall process. These results indicate that this plant improved its hygienic performance considerably and that the HACCP plan was an effective and valuable tool for achieving this improvement. The APC data were sufficient for validation and verification of the HACCP system that was successfully implemented to improve hygienic performance.

Aerobic and Anaerobic Microbiology of the Immersion Chilling Procedure During Poultry Processing

The development of treatments to reduce bacterial numbers on poultry carcasses is important for the overall hygienic quality of birds. The important washing effect of the immersion chilling procedure is discussed. Systematic monitoring of fecal bacterial indicators as well as some classic pathogens was performed at selected critical points in a water chiller ecosystem. Clostridium perfringens, fecal coliforms, Enterococcus sp., and Streptococcus sp. were found in all water chiller samples. The temperature of the chiller ecosystem varied according to location: Escherichia coli and Salmonella sp. were found at 16 degrees C, compared with the 4 degrees C location, where these species were found in lower numbers. Moreover, the psychrotrophic bacterium Pseudomonas was found only at this last location. The temperature of the water during the immersion chilling procedure was unfavorable for the growth of Campylobacter sp., whose presence was always strictly associated with a pH close to 6. Spore forms of C. perfringens were persistent in all locations and seemed to be a reliable indicator of contamination of the water chiller ecosystem.

The role of contaminated feed in the epidemiology and control of Salmonella enterica in pork production

Food animal producers have ethical obligations to reduce the risk of foodborne hazards in animals under their care. Contaminated feed is a recognized source of Salmonella infection of food animals and regulations to control Salmonella contamination of animal feed have existed in some countries for decades. The impact of reducing Salmonella contamination of animal feeds on the risk of human foodborne salmonellosis is difficult to assess, and is likely to vary among food animal industries. In the context of U.S. pork production, factors that may attenuate or negate the impact (on public health) of regulatory interventions to control Salmonella in commercial feed include widespread use of on-farm mixing of swine feed; incomplete decontamination of feed during processing; post-processing contamination of feed at feed mills or in transportation or on-farm storage; the multitude of nonfeed sources of Salmonella infection; an apparently high risk of post-farm infection in lairage; and post-harvest sources of contamination. A structured survey of the extent of Salmonella contamination of animal feed in the United States is necessary to enable more informed debate on the feasibility and likely efficacy of enforcing a Salmonella-negative standard for animal feeds to reduce the incidence of human salmonellosis.