A virus infection that attacks the liver cells. Can be transmitted through contaminated food. Uncooked salad ingredients, raw shellfish. Most cases have been traced to infected food handlers. Potato salad is a frequent vehicle for one of the nastier foodborne illnesses, staphylococcal food poisoning, although it can also do the same favor for salmonellosis, Bacillus cereus, E. coli, campylobacter, Norovirus and Shigella.