AimsEvaluating the effect of a commercially available organic acid water additive in conventional broiler production on Campylobacter spp. Methods and ResultsThe organic acid water additive was added to the drinking water from chick housing to catching in three consecutive rearing cycles. The broiler performance data were evaluated, and the load of thermophilic Campylobacter spp. was analysed in water, feed and the environment as well as determined in caecum content and on carcasses at the abattoir according to ISO 10272:1.2-2002. The results indicated that permanent application of acidified drinking water did not have detrimental effects on production parameters or animal welfare. The quantitative results obtained at slaughter were ambiguous, but suggested a reduced carriage of Campylobacter spp. by the flock and in caecum content. Such reduction did not result in lower Campylobacter carriage of the carcasses after slaughter. ConclusionsOrganic acids in drinking water of broilers can partly reduce the caecal Campylobacter spp. load, but this did not reduce carcass contamination. Significance and Impact of the StudyBroiler meat is a major source of foodborne campylobacteriosis. The public health would considerably benefit from controlling Campylobacter in the food chain. The addition of organic acid to drinking water of broilers can potentially lower the caecal carriage in primary production. However, in this field trial, a commercial product failed to have an impact on the bacterial load after slaughter.