Rapid and reliable detection of foodborne pathogens : Exploring Campylobacter ecology in enrichments to improve detection

Abstract

In 1988, Black et al. conducted a trial, in which they administered adult volunteers with food artificially contaminated with different concentrations of two C. jejuni strains to establish a dose-response relation for Campylobacter infections from food . They found not only that one of the strains was more likely to cause illness and that illnesses were more severe, but they also concluded that already 800 cells were sufficient to cause campylobacteriosis . Later, mathematical models and microbiological risk assessments were used to estimate a dose-response relation. Medema et al. (1996) suggested that the ingested dose resulting in illness was 9•10 4 cells but also mentioned that the risk differed between C. jejuni isolates. It is well established that C. jejuni is responsible for most foodborne Campylobacter infections, but C. coli has been recognized to be responsible for a fourth of all campylobacteriosis cases (Gürtler et al., 2005;Inglis et al., 2011) and symptoms are similar to those induced by C. jejuni . It is important to mention that, although it has been suggested that the infectious dose of C. jejuni is much lower than other foodborne pathogens (Kothary and Babu, 2001), no clear dose-response relation can be established as it is not only dependent on the pathogenicity of the strain but on other factors like the health state and demographics of the individuals ingesting the Campylobacter cells. Although everyone can be infected by Campylobacter, infections are predominantly common in certain age groups; in industrialized countries, the incidence rate is generally higher in young children until the age of four (