The role of hens' eggs in outbreaks of salmonellosis in north Spain.

Most outbreaks of salmonellosis occurring in Spain are transmitted by hens' eggs. This prompted a study on the incidence of Salmonella in eggs. Salmonella was found in 5 of 372 eggs associated with foodborne disease; one strain was isolated from the inside of the egg. In 998 eggs not associated with human salmonellosis, Salmonella was found on 6 occasions, including once inside the egg. These percentages are in general higher than those found in other Western countries. The possibility of eggs being contaminated before laying is discussed and an approach for controlling salmonellosis transmitted in this way is presented.