Colony forming unit counts of Campylobacter jejuni were serially determined in a variety of microcosms in which growth was not expected. Unremitting decline in colony counts occurred in nutrient-free systems, however, transient increases were observed in human faecal emulsions and nutrient media on storage at between 1 and 25³C. The phenomenon, which was more pronounced at lower temperatures, could not be attributed to sampling errors, cell clumping or the influence of minor fluctuations in experimental conditions. C. jejuni is capable of either growth at low temperatures or transition between temporarily nonculturable and culturable states. z 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V.

Colony forming unit counts of Campylobacter jejuni were serially determined in a variety of microcosms in which growth was not expected. Unremitting decline in colony counts occurred in nutrient-free systems, however, transient increases were observed in human faecal emulsions and nutrient media on storage at between 1 and 25 degrees C. The phenomenon, which was more pronounced at lower temperatures, could not be attributed to sampling errors, cell clumping or the influence of minor fluctuations in experimental conditions. C. jejuni is capable of either growth at low temperatures or transition between temporarily nonculturable and culturable states.