RODALE NEWS, EMMAUS, PA—Don’t think you’re a dork if you walk around with a meat thermometer. “It’s cool!” says Bradley Marks, PhD, professor of biosystems engineering at Michigan State University in East Lansing. Of course, he’s a food-safety expert and knows all about the nasty bacteria that can lurk in meat—particularly Salmonella. Even whole cuts of meat aren’t safe from it, as was once thought. A 2008 study published in the Journal of Food Science, he and colleagues found that whole cuts of meat, such as steak, can be contaminated internally with Salmonella. And it’s harder to kill with heat when compared to ground meat. Medium-rare lover? You better read on.
THE DETAILS: Researchers sampled ground and whole cut pieces of beef from the same original lot and contaminated it with Salmonella, a type of bacteria found in the digestive tracts of humans and animals. Because it lives in animals, the bacterium can contaminate the meat during the slaughtering process, explains Marks. Workers who don’t wash their hands, or use contaminated surfaces, can also spread the bacteria. When people eat food contaminated with Salmonella, they develop fever, abdominal cramps, and diarrhea, which can last for up to a week. Victims usually recover without treatment, though a person with a weak immune system can develop more serious problems. The interior portions of whole cuts of beef like steaks or roasts have long been assumed to be sterile, but contamination and survival of pathogens have been reported. This study found Salmonella hiding deep inside whole cuts of meat.
WHAT IT MEANS: The study is relevant to commercial producers, but it provides some valuable insight for anyone who cooks and eats meat. While ground meat is more likely to be contaminated with Salmonella because a contaminated outer piece is mixed throughout the meat, Marks’ latest study shows that the bacterium also occurs in whole cuts, where it’s harder to kill with heat. It likely finds its way to the center of the meat—the part that takes the longest to heat up—through a marinating or tenderizing process. Once the bacterium make it to the center of the meat, the coldest point, it’s harder to kill off by cooking. “Don’t assume the whole muscle product doesn’t have bacteria, because it can,” says Marks. “If there’s contamination on the surface, and you marinate it, then the muscle absorbs it. When [the marinade is] going in, Salmonella cells can go along for the ride.”
Here's how to make sure your meat won't make you sick:
• Never leave home without your meat thermometer.OK, maybe that’s a bit much, but if you’re going to a picnic or other function, particularly where there’s grilling going on, it’s probably not such a bad idea to bring one. That’s because grilled meat has a tendency to brown prematurely, tricking us into thinking it’s fully cooked when it’s really not. A digital meat thermometer runs about $15, a slight investment that can really pay off. “Many of the rules of thumb about cooking meat, like, ‘cook until the juices are clear,’ aren’t true,” says Marks. “None of them will tell you whether you’ve achieved sufficient time and temperature to kill bacteria.”
• Make it hot. “Ground meat is a greater risk than for a whole muscle product. However, the risk of there being a pathogen in the center of a whole muscle product, like roast, is not zero,” explains Marks. The USDA lists the following as safe minimum internal temperatures (all temperatures are in Fahrenheit): Whole poultry, poultry breasts, and ground poultry should reach at least 165 degrees in the middle. All cuts of pork and beef hamburgers should reach 160 degrees; medium beef, veal, or lamb steaks, roasts, and chops should hit 160 degrees; medium-rare should reach 145 degrees. When cooking roasts, ham, or other thick cuts of meat, consult the USDA’s Holiday Meats Guide or its beef cooking times info. For instance, a ¾-inch thick steak should be broiled or grilled for four to five minutes on each side, and reach an internal temperature of at least 145 degrees to make sure it’s safe to eat. “Can’t just singe on both sides and assume it’s OK,” Marks warns.