INTERREGIONAL FOODBORNE SALMONELLOSIS OUTBREAK DUE TO POWDERED INFANTFORMULA CONTAMINATED WITH LACTOSE-FERMENTING SALMONELLA VIRCHOW

Spain's Salmonella surveillance system backed by regionally-based epid emiologists around the country made it possible to detect and halt the spread of a foodborne salmonellosis outbreak due to powdered infant f ormula contaminated with a lactose-fermenting strain of Salmonella vir chow. Forty-eight cases involving children, mostly under 7 months old, were detected in 14 out of Spain's 17 Regions. The outbreak started i n January and ended in June 1994. All cases were microbiologically con firmed. The implicated strain had a 3.6 kb plasmid, was susceptible to all antimicrobials tested except nitrofurantoin and was phagetype 4a. Isolates from 8 of 24 Brand ''A'' milk samples tested had the same ch aracteristics as case isolates. All affected/suspect batches of Brand ''A'' milk were destroyed and the product withdrawn from sale, which l ed to the end of the outbreak. This incident underscores the importanc e of maintaining surveillance systems able to detect and prevent foodb orne outbreaks and alert to the possibility of isolating unusual lacto se-fermenting Salmonella serotypes in especially sensitive food produc ts.