Do the Escherichia coli European Union shellfish safety standards predict the presence of Arcobacter spp., a potential zoonotic pathogen?

The genus Arcobacter comprises Campylobacter-related species, considered zoonotic emergent pathogens, the presence of which in water has been associated with fecal pollution. Discharges of fecal polluted water into the sea have been considered as one of the main reasons for the presence of Arcobacter in shellfish, and this may represent a risk for public health. In this study, the European Union shellfish food safety criteria based on levels of Escherichia coli were studied in relation to their capacity to predict the presence of Arcobacter species. In addition, the accumulation factor (AF) that measures the concentration ratio between the microbes present in the shellfish and in the water, was also studied for both bacteria. The results show that the presence of E. coli correlated with the presence of the potentially pathogenic species A. butzleri and A. cryaerophilus. However, in 26.1% of the shellfish samples (corresponding to those taken during summer months) E. coli failed to predict the presence of, for instance A. butzleri and A. skirrowii, among other species. In the rest of the samples a significant correlation between the concentration of E. coli and Arcobacter spp. (mussels and oyster; R2=0.744) was found. This study indicates that the presence of E. coli can predict the presence of pathogenic Arcobacter species in shellfish samples harvested from water with temperatures lower than 26.2°C. Consumption of shellfish collected at higher temperatures which may not be permissive to the growth of E. coli but does allow growth of Arcobacter spp., may represent a risk for consumers.