Baseline data from a Belgium-wide survey of Campylobacter species contamination in chicken meat preparations and considerations for a reliable monitoring program

Abstract

From February to November 2007, chicken meat preparations (n = 656) were sampled at 11 processing companies across Belgium. All samples were tested for Campylobacter by enrichment culture and by direct plating according to standard methods. Almost half (48.02%) of the samples were positive for Campylobacter spp. The mean Campylobacter count was 1.68 log(10) CFU/g with a standard deviation of +/- 0.64 log(10) CFU/g. The study revealed a statistically significant variation in Campylobacter contamination levels between companies; processors with a wider frequency distribution range of Campylobacter counts provided chicken meat preparations with higher Campylobacter incidences and concentrations. There was no significant difference between the counts of Campylobacter spp. in various preparation types. However, the Campylobacter counts and incidences in chicken wings were the highest and portioned-form products (legs, wings, and breasts) showed a higher probability of being Campylobacter positive compared to minced-form products (sausages, burgers, and minced meat). The proportion of Campylobacter-positive samples was significantly higher in July than in other months. Recovery of Campylobacter spp. recovery by direct plating was higher (41.0%) compared to detection after enrichment (24.2%). Statistical modeling of the survey data showed that the likelihood of obtaining a positive result by enrichment culture increases with an increase in the Campylobacter concentration in the sample. In the present study, we provide the first enumeration data on Campylobacter contamination in Belgian chicken meat preparations and address proposals for improving Campylobacter monitoring programs.

FIG. 1.

Frequency distribution of Campylobacter counts in 656 chicken meat preparation samples. The scale on the y axis shows the number of samples that fall within the range of Campylobacter counts represented by the bars on the x axis.

FIG. 2.

Variation in frequency distribution of Campylobacter counts in chicken meat preparation samples over companies. The 11 companies are identified by the letters A to K, and the two dashed lines denote contamination levels of 1 and 2 log₁₀ CFU/g. The scale on the y axis shows the number of samples that fall within the range of Campylobacter counts represented by the bars on the x axis.

FIG. 3.

Variation in Campylobacter counts in 656 chicken meat preparation samples from 11 Belgian producers, distributed according to product forms (A) and preparation types (B). The line inside each box represents the median value, and the upper and lower hinges represent the 75th and the 25th percentiles, respectively. The highest Campylobacter contamination counts (values over the 90th percentile) are shown as circles.

FIG. 4.

Occurrence of Campylobacter bacteria in Belgian chicken meat preparations from February to November 2007. ▴, percentage of positive samples; dotted columns, number of samples tested; squared columns, number of Campylobacter-positive samples.