Y. Ghafir

An Efficient Sampling Technique Used To Detect Four Foodborne Pathogens on Pork and Beef Carcasses in Nine Belgian Abattoirs

The method presented in this paper should prove useful in assessing the effectiveness of HACCP plans developed in slaughterhouses. Samples were collected by swabbing well-defined areas of pork and beef carcasses with sterile gauze. Between 160 and 420 half-carcasses were swabbed in each of nine pork or beef slaughterhouses. Swabs from five carcasses were placed in the same sterile Stomacher bag, constituting a single composite sample. Standard or validated analytical methods were used to isolate and characterize four foodborne pathogens. Salmonella spp., Listeria monocytogenes, Campylobacter spp., and verocytotoxin-producing E. coli were detected, respectively, in 27, 2, 2, and 14% of the pork samples and 0, 22, 10, and 5% of the beef samples. Of the 10 samples positive for E. coli O157, only one yielded an isolate confirmed to be enterohemorrhagic. Since Salmonella spp. appear as the main contaminant port (27%) and L. monocytogenes as the main containment of beef (22%), any slaughterhouse sampling plan should include testing for the former in the case of pork carcasses and for the latter in the case of beef carcasses. One should also test regularly for the presence of E. coli O157 and Campylobacter spp. in pork and beef abattoirs. The method presented here is an easy way to assess the contamination rate of carcasses at the end of the slaughtering process.

Salmonella contamination of pigs and pork in an integrated pig production system.

This paper describes the monitoring of Salmonella in a closed pig production system in Belgium over a 2-year period. A sampling scheme including animal feeds and carcasses was designed to cover the entire chain of production from farrow to finishing pigs. Salmonella was detected by a method based on the use of semisolid Rappaport-Vassiliadis as a selective medium. The serotypes of the isolated strains were determined, and the antibiotic resistance of these strains to six antibiotics was also investigated. Feeds were found to be more contaminated than expected (10.2%, 34 of 332 samples). The percentage of positive fecal samples for pregnant sows (8.1%, 11 of 135 samples) was significantly higher than that for young and lactating sows (2.9%, 11 of 378 samples) (P<0.05). The percentage of positive samples for colon contents collected at the slaughterhouse (47.3%, 88 of 186 samples) was significantly higher than that for feces collected during the fattening stage (5.6%, 18 of 320 samples) (P<0.001). For carcass swab samples, the observed prevalence was 11.2% (17 of 152 samples). On farms, Salmonella recovery levels were higher for overshoe samples than for fecal samples, except for pregnant sows. Salmonella Typhimurium was the most frequently isolated serotype (32.2%, 55 of 171 samples), while Salmonella Brandenburg was predominant in the colon contents collected at the abattoir (21.4%, 18 of 84 samples). Feeds harbored a wide diversity of serotypes of minor epidemiological significance. Of 55 isolated strains of Salmonella Typhimurium, 11 (20%) were resistant to tetracycline, ampicillin, choramphenicol, streptomycin, trimethoprim, and nalidixic acid (R Type TeAmCSNa), while 12 (21.8%) were resistant to all of these antibiotics except nalidixic acid (R Type TeAmCS). The majority of Salmonella Typhimurium strains that exhibited resistance to more than four antimicrobial agents were characterized as Salmonella Typhimurium DT104 or as being closely related to Salmonella Typhimurium DT104 (7 of 12 isolates). In conclusion, our system of surveillance is effective in identifying most points of contamination in the production chain and will be useful in ongoing efforts to develop a Salmonella-free production system.

Hygiene indicator microorganisms for selected pathogens on beef, pork, and poultry meats in Belgium.

Several bacterial indicators are used to evaluate hygiene during the meat slaughtering process. The objectives of this study were to assess the Belgian baseline data on hygienic indicators and the relationship between the indicators and zoonotic agents to establish hygiene indicator criteria for cattle, pig, and chicken carcasses and meat. The study used the results from the official Belgian surveillance plan from 2000 to 2003, which included the monitoring of Escherichia coli counts (ECC), Enterobacteriaceae counts (EC), aerobic colony counts (ACC), and Pseudomonas counts (PC). The sampling method was the wet and dry swabbing technique for cattle and pig carcasses and neck skin excision for broiler and layer chicken carcasses. The 75th and 95th percentiles of ECC were -0.20 and 0.95 log CFU/cm2 for cattle carcasses, 1.20 and 2.32 log CFU/cm2 for pig carcasses, and 4.05 and 5.24 log CFU/g for chicken carcasses. The ACC were 2.1- to 4.5-log higher than the ECC for cattle, pigs, and chickens. For cattle and pig carcasses, a significant correlation between ECC, EC, and ACC was found. ECC for pork and beef samples and EC in pig carcasses were significantly higher in samples contaminated with Salmonella. In poultry samples, ECC were in general higher for samples containing Salmonella or Campylobacter. Thus, E. coli may be considered as a good indicator for enteric zoonotic agents such as Salmonella for beef, pork, and poultry samples and for Campylobacter in poultry samples.

Belgian surveillance plans to assess changes in Salmonella prevalence in meat at different production stages

From 1997 to 1999, the prevalence of Salmonella was assessed at different stages through the pork, poultry, and beef meat production chains. Different dilutions of the initial sample suspension were analyzed to provide a semiquantitative evaluation of Salmonella contamination and to determine the most representative dilution necessary to detect a reduction in prevalence. An average of 300 samples for each type of meat were analyzed. According to Fishers exact test, the dilution to be used to detect a reduction in prevalence was chosen based on an initial prevalence of 20 to 26%. Based on this introductory study, a new sampling plan representative of the nationwide Belgian meat production process was used from 2000 through to 2003. This study confirmed the consistently high rate and level of contamination of poultry meat: broiler and layer carcasses were the most contaminated samples followed by broiler fillets and poultry meat preparations. A constant and significant decrease in Salmonella prevalence was observed for pork carcasses, trimmings, and minced meat and for beef minced meat. Less than 3% of beef carcasses and trimming samples were positive for Salmonella. The Belgian plan, as utilized from 2000 to 2003, was suitable for monitoring of zoonoses because the sampling plan was representative of nationwide production processes, covered all periods of the year, and was executed by trained samplers and the analyses were carried out by recognized laboratories using an identical analytical method.

Analysis of scintigraphical lung images before and after treatment of horses suffering from chronic pulmonary disease.

Scintigraphical analysis of the ratio of inhalation (i) to perfusion (Q) was designed to determine whether chronic pulmonary disease in horses induced mismatches in i/Q and to assess whether medical treatment would restore an I/Q distribution pattern identical to that of control horses. In addition, the results of the I/Q analysis were correlated with the alveolar-arterial PO2 difference (AaDO2). The I/Q matching found in a group of control horses was compared with the I/Q analysis of a group of diseased horses before and after their clinical signs had been treated. The analysis indicated that there was mismatching between I and Q before they were treated. The treatment improved the diseased horses, pulmonary function but there was still heterogeneity in the I/Q distribution after they had been treated. The i/Q analysis parameters were well correlated with the ratio of ventilation (VA) and pulmonary blood flow (Q), evaluated by the determination of AaDO2.

Comparison of swabbing and destructive methods for microbiological pig carcass sampling

Aims:  To compare the Belgian swabbing sampling method for pig carcasses with the reference destructive method with regard to Escherichia coli and aerobic plate counts, Salmonella and Campylobacter prevalence and their relationship.