Risk factors for outbreaks of infectious intestinal disease linked to domestic catering.

The epidemiology of general outbreaks of infectious intestinal disease associated with domestic catering for large numbers is described and compared with foodborne outbreaks in other settings. From 1 January 1992 to 31 December 1994, the PHLS Communicable Disease Surveillance Centre identified 101 foodborne general outbreaks of infectious intestinal disease associated with domestic catering in England and Wales (16% of all foodborne outbreaks). Salmonella species were associated with 77 of the 101 outbreaks and S. enteriditis phage type 4 accounted for 57. Small round structured viruses were implicated in five outbreaks, Clostridium perfringens in four, Bacillus cereus in two, and Campylobacter sp and Escherichia coli in one each. No pathogen was identified in 11 outbreaks. Outbreaks occurred most commonly in summer. The commonest vehicles implicated were poultry/eggs in 44 outbreaks, desserts in 13, and meat/meat products in nine. Salad/vegetables, sauces, and fish/shellfish were each implicated in eight outbreaks. Raw shell eggs were implicated in a fifth of outbreaks. Inappropriate storage was the commonest fault, reported in association with 50 outbreaks (ambient temperature for long periods before serving in 29), inadequate heat treatment was reported in 35, cross contamination in 28, an infected food handler in 11, and other faults in 14. Outbreaks associated with catering on domestic premises were independently more likely than outbreaks in other settings to be associated with salmonellas, inappropriate storage of food, and consumption of poultry, eggs, or sauces. Public health services need to direct messages about the use, preparation, and storage of food to those who cater on domestic premises.