It wasn’t the ice cream plant or the people who worked there. It wasn’t the chocolate flavoring that went into the ice cream. The source of the largest Salmonella outbreak in U.S. history was the tanker trailers that transported the pasteurized “premix” to a Schwan’s plant in Minnesota, where it was made into ice cream.

   A few months before the 1994 outbreak, the trucking company used by Schwan’s started transporting greater quantities of unpasteurized eggs from plants in Nebraska and Iowa to egg processors in Minnesota.

   “To save time, drivers could elect to bypass the cleaning procedure after unloading the eggs,” explained Thomas Hennessy of the Minnesota Department of Health.

   The damage: an estimated 224,000 people sickened. In Minnesota, over half the victims had diarrhea that lasted a week or more plus (in most cases) fever and chills and (in nearly half) bloody stools. A quarter had to be hospitalized.

   What’s more, when researchers at the CDC surveyed Schwan’s customers in Georgia, they found that in nearly a third of the 72 households that had Schwan’s ice cream in the freezer when a family member heard about the recall, someone in the family later ate the ice cream anyway.

   “In 90 percent of those households, people just didn’t believe there was a problem with the ice cream,” says the CDC’s Laurence Slutsker.
 

 Watch for recalls in the local paper or on the news. Don’t eat the food, even if it appears to be safe.

 Avoid raw (unpasteurized) milk and cheeses made from raw milk, unless they’ve been aged for at least 60 days (it should say on the label). All could harbor a bacterium called Listeria, which is especially dangerous for pregnant women and their fetuses.

 You can also get Listeria from soft cheeses (like feta, Brie, Camembert, blue-veined, or Mexican-style “queso blanco”—whether they’ve been pasteurized or not), but not from cottage cheese, cream cheese, or hard cheeses.