Cookbooks' Missing Ingredient? Food Safety

Cookbooks may be leaving out a crucial step in recipes: food safety. The vast majority of recipes found in popular cookbooks offer little useful advice to keep you from getting sick, a new study finds.

In a review of nearly 1,500 recipes from popular cookbooks, researchers found that only 123 recipes, or about 8 percent, mentioned cooking meat to a specific temperature.

"Cookbooks tell people how to cook," but the researchers wondered "whether they were telling people to cook in a way that could affect the risk of contracting foodborne illness," Ben Chapman, a professor of food safety at North Carolina State University and the study's senior author, said in a statement. [Top 7 Germs in Food That Make You Sick]

Previous research has suggested that in the U.S., up to 3.5 million cases of foodborne illnesses result from improperly cooking meat or other animal proteins, according to the study, which was published March 17 in the British Food Journal. 

In the study, the researchers reviewed recipes in cookbooks that had been on The New York Times best-sellers list between September 2013 and January 2014. They examined recipes for cooking meat, poultry, seafood and eggs, looking for several factors that impact food safety, including the internal temperature recommended for the meat. They also kept an eye out for common "food-safety myths" as they read the recipes — for example, advice that you should wash raw chicken in the sink (you shouldn't).

They found that some recipes recommended an internal temperature for meat that was incorrect: Of the 123 recipes that mentioned a temperature, 34 recipes (or about 28 percent) recommended cooking meat to temperatures that were too low to kill bacteria or parasites, according to the study. And 27 of the recipes (about 22 percent) didn't bother recommending that the chef use a meat thermometer, the researchers found.

For example, several chicken recipes instructed home chefs to cook the chicken to 160 degrees Fahrenheit (71.1 degrees Celsius), rather than 165 degrees Fahrenheit (73.9 degrees Celsius), which is what food safety experts recommend. In some instances, the recipes said that the chicken's internal temperature would continue to increase after the chicken was removed from the heat; however, no studies back this up, the researchers wrote.

Pork recipes were the most likely to include a specific temperature to cook the meat to, according to the study. Ground-beef recipes were the least likely to include an internal temperature, and instead, those recipes often told readers to evaluate doneness by looking at the color of the meat or the color of its juices, the researchers found.

And although egg recipes did include correct temperatures, they rarely told readers to use a thermometer, the study found.

Other indicators

Although almost every recipe in the study included directions to use some indicator to determine whether the animal protein had been cooked thoroughly, in many cases, these indicators aren't backed up by scientific studies, the researchers said.

For example, the most common indicator that a recipe was done was cooking time, according to the study. But cooking time can be "particularly unreliable, because so many factors affect how long it takes to cook something: the size of the dish being cooked, how cold it was before going in the oven, differences in cooking equipment and so on," lead study author Katrina Levine, an agricultural and human sciences researcher at North Carolina State University, said in a statement. [7 Foods You Can Overdose On]

Internal cooking temperatures, on the other hand, are "based on extensive research, targeting the most likely [germs] found in each food," Levine said.

In some cases, recipes included two recommendations that contradicted each other — for example, "Cook the turkey for 3 hours or until the internal temperature reaches 165 degrees Fahrenheit."

Other unreliable indicators included the color or texture of the meat, or the instruction to cook until "simmering," the researchers found. In some cases, unusual language was used to explain doneness, such as "meltingly," "soft curds" or simply "totally done," the researchers said.

Avoiding cross-contamination

Very few of the recipes included advice to avoid cross-contamination, which occurs when germs from one of the foods in the recipe is transferred to something else, according to the study.

For example, only 29 recipes recommended using separate or clean cutting boards, utensils and dishes for raw and cooked foods, the researchers found. And only 12 recipes recommended that people wash their hands after touching raw animal protein.

Several recipes, the researchers noted, instructed people to wash raw poultry— a practice that can actually spread germs, rather than wash them away. Germs are spread because the water can splatter them around the sink and to other surfaces in the kitchen.

Originally published on Live Science.