C . T HO M AS , D . J. HI L L A ND M .M AB E Y. 1999. Batch microcosms containing various water types (de-ionized and river water with or without sediment), incubated at a range of temperatures (5-37°C), were used to facilitate a comparative evaluation of the significance of such variables and their interactions upon the collective and individual survival of four species of thermophilic Campylobacter. All variables significantly influenced (P ³ 0·031) population decay rates. Minimal decay for the group was identified at low temperatures (5°C) in river water, i.e. nutrient-containing microcosms. Collective decay rates within river water microcosms were significantly decreased (P 0·03) from those observed in de-ionized water, particularly at environmental temperatures (5 and 15°C). However, the increased nutrient levels observed in sedimentcontaining microcosms did not significantly (P 0·41) reduce population decay rates. Overall, Camp. jejuni populations demonstrated the most resilience to the environmental stressors evaluated, with the exception of 15°C where Camp. lari was the most persistent. Campylobacter coli and Camp. upsaliensis demonstrated comparable survival characteristics but were less resilient than Camp. jejuni and Camp. lari. These observations identify the suitability of water systems as a reservoir and medium for Campylobacter infection, and potentially identifies Camp. jejuni and Camp. lari as the main protagonists of water-mediated campylobacteriosis.

SUMMARY Members of the genus Campylobacter have established themselves as the most common human gastro‐enteric pathogens throughout much of the developed world. The ubiquitous distribution of Campylobacter spp. in animal reservoirs and food products derived thereof make such vehicles primary risk factors in contracting campylobacteriosis. The contamination rates, identification of common pathogenic serotypes and extended survival of Campylobacter in surface waters illustrates the potential, but yet to be quantified, campylobacteriosis risk associated with untreated water. The existence and potential pathogenicity of viable but nonculturable forms of Campylobacter remains a contentious subject. Furthermore, the role of such forms in the epidemiology of Campylobacter related disease and their involvement in the large number of waterborne gastroenteritis outbreaks from which a disease agent cannot be isolated remains to be fully clarified. This article presents a survey of current perspectives with regard to the survival and epidemiology of Campylobacter spp. in natural water systems.

Aims: To study the survival processes of thermophilic Campylobacter spp. within a modelled aquatic system and particularly the involvement and survival potential of viable but nonculturable forms. Methods and Results: The survival and morphological characteristics of populations of thermophilic Campylobacter species exposed to simulated aquatic conditions were examined using a combination of cultural and microscopic techniques. Populations underwent progressive decay when exposed to simulated aquatic conditions. The rates of population decay were observed to be signi®cantly greater at the higher temperature (20°C) with a rapid transition of the dominant sub-populations from non-stressed to dead cells occurred within 3 days. At 10°C the rate of culturability loss was much reduced with substantial development (approx. 80% of total population) of viable but non-culturable (VBNC) populations by all species within 3 days, declining to represent approximately 5±25% of the total population at day 60. Signi®cant differences (P < 0á001) were identi®ed between decay rates as a consequence of different species, sub-populations and temperature but not between sub-populations of different species. Morphological variants including spiral, elongated spirals and rods, short rods and coccoid forms were identi®ed. The endpoints of morphological transition were temperature-independent and isolate-speci®c yet the rate of morphological transition was directly related to temperature and approximately equivalent between species. Conclusion: The VBNC state is a transitory stage in the degeneration of Campylobacter population within the aquatic environments simulated during this study. Signi®cance and Impact of the Study: VBNC cells form the most persistent, viable, potentially pathogenic sub-population of Campylobacter populations exposed to aquatic stress conditions.

C . T HO M AS , D . J. HI L L A ND M . M AB E Y. 1999. Campylobacter jejuni strains demonstrate a variety of growth phase-linked distinct morphological forms when grown in liquid culture. The typical spiral form of the organism, evident during logarithmic phase, undergoes elongation during stationary phase before becoming coccoid via the formation of membrane blebs and budded forms in decline phase. Cellular elongation and coccoid formation occurred despite the inhibition of protein synthesis and without a detectable change in the protein components of the inner and outer cell membranes.

Discusses research recently carried out by Delyn BC and the Audit Commission in its search for performance indicators for the environmental health food safety function, and how this can facilitate improved analysis of “Hazard” and “Risk Management” performance in food premises. Analysis has been made of risk assessment scores from 8,000 food premises inspections carried out by Environmental Health Officers from varying LAs, which have been transferred into a computerized database, located at Delyn BC. Interpretation and observation of the results and illustrations has revealed some fascinating similarities between the LA data presented. Implementation of these proposals could provide more uniform risk analysis and enhanced enforcement standards in food premises, leading to improved food safety by enabling the more accurate focusing of resources and efforts to where they are most needed and effective.