Raw Hamburger: An Interstate Common Source of Human Salmonellosis

Abstract

An interstate common-source outbreak of salmonellosis was first detected in the United States in September and October, 1975, when a tenfold increase in Salmonella newport isolates was noted through routine salmonella surveillance by the Colorado Department of Health. Eighteen primary cases with a distinctive antibiotic resistance pattern (tetracycline, streptomycin, and sulfonamides) were evaluated in a case-control study, and illness was found to be associated with eating raw hamburger (p less than .001) from any store of one grocery chain (p less than .001). A Dallas, Texas, processing plant that supplied the Colorado markets also supplied other states, and these other states were alerted. Maryland discovered nine S. newport isolates with the same antibiogram and, as in the Colorado outbreak, illness was associated with eating raw or very rare ground beef from the same grocery chain (p less than .03). A third outbreak of S. newport with the same antibiogram occurred on a Florida military base. S. newport with the same antibiogram and a phage lysis pattern identical to those of the human epidemic isolates was cultured from frozen hamburger recovered in Colorado and Florida. The associated hamburger originated at the same Dallas, Texas, processing plant. A source of the epidemic strain was not identified, but the organism probably originated before delivery to the plant.

Salmonella and broiler processing in the United States: Relationship to foodborne salmonellosis

“…Likewise, an outbreak of S. Typhimurium was linked to artificial ice cream containing about 4 log CFU, and had an attack rate of 55% (Armstrong et al, 1970). Outbreaks associated with high fat products have been shown to cause disease with much lower levels of organism, for instance, chocolate bars with less than 10 CFU of S. napoli per gram (Greenwood & Hooper, 1983) and hamburger with as low as 6 CFU per gram (Fontaine et al, 1978). The infectious dose likely also varies with patient age and health as well as the composition of the food with which the pathogen is associated.…”

Molecular Characterization of Cephalosporin-Resistant Salmonella enterica Serotype Newport Isolates from Animals in Pennsylvania

“…Salmonella serotype Newport has been isolated from food sources such as potato salad (11), hamburger (7,26), chicken (1), precooked roast beef (24), ham or pork (13,16), fish and seafood (10), and alfalfa sprouts (29,30). In the United States, serotype Newport has been implicated in several large outbreaks of human salmonellosis, and this serotype is consistently among the top 10 salmonella serotypes isolated from human infection.…”

Outbreak of Multidrug-Resistant Salmonella enterica Serotype Typhimurium Definitive Type 104 Infection Linked to Commercial Ground Beef, Northeastern United States, 2003-2004

“…Eating undercooked ground beef appears to be a long-standing cultural practice, because outbreaks of infection in which this behavior has been documented have occurred for decades [26,27]. Because it is unlikely that untreated raw meat will ever be microbially safe for direct consumption, consumers should be discouraged from eating or tasting raw or undercooked ground beef.…”