Steak and Burgers Are Both Beef. So Why Is One Riskier to Eat Rare?

Why It Works

• On an intact steak, harmful bacteria, if present, are generally found on the surface. Grinding beef, however, can distribute bacteria throughout the meat—even when the outside of a burger is nicely browned.

• To minimize the risk of foodborne illness, the USDA recommends cooking ground beef to an internal temperature of 160°F (71°C).

A rare steak with a deeply browned crust and a warm, red center can be pretty irresistible, whether you're ordering at a steakhouse or cooking it yourself at home. The same goes for a juicy, medium-rare burger . But eating a rare burger poses a greater risk of foodborne illness than eating a rare steak. The difference comes down to how meat is processed, and where harmful bacteria may be lurking. We spoke with two food scientists and a butcher to understand the risks and how to minimize them.

How Does Beef Get Contaminated?

Some harmful bacteria, including Shiga toxin-producing E. coli, live in cattle's digestive tracts and can be shed in their manure, says Randall Phebus , PhD, a professor at Kansas State University's Department of Animal Sciences and Industry. During slaughter and processing, bacteria from an animal's hide or digestive contents can be transferred to the surface of the meat, either directly or through contaminated equipment.

Although USDA-inspected slaughterhouses are required to follow sanitation and food safety procedures to minimize contamination, these measures can't completely eliminate the risk. And because bacteria can't typically be detected by sight, smell, or taste, consumers can't reliably determine whether their raw beef is contaminated.

Why Grinding Beef Changes the Risk

In an intact cut of beef that hasn't been injected or mechanically tenderized, harmful bacteria introduced during processing are generally found on the surface. That's because the meat's interior hasn't been directly exposed to the environment or processing equipment, and bacteria don't readily penetrate intact muscle tissue. Even if the center of the steak remains rare, searing the exterior can kill harmful bacteria on its surface.

Grinding beef changes the equation. As beef passes through a grinder, bacteria present on its surface can be distributed throughout the meat. Grinding also increases the meat's surface area, potentially exposing more of it to contamination from other pieces of beef or the grinding equipment. As a result, bacteria may be present deep inside a burger patty, where they can survive if the meat isn't cooked to a sufficiently high internal temperature—even if the exterior is thoroughly seared.

The risks can be exacerbated by the scale of commercial ground beef production. In a 2012 study published in the peer-reviewed journal PLOS ONE , researchers estimated that 411 to 1,367 cattle contributed to each of six roughly one-metric-ton batches of ground beef at a large beef processing facility. Although these findings aren't representative of the entire meat industry, they illustrate how meat from hundreds of animals can be combined into a single batch. If meat from even one animal carries harmful bacteria, grinding and mixing it with other beef can spread those pathogens throughout a much larger batch. Producing ground beef at this scale helps keep prices down, says Pip Freeman, a butcher, chef, and owner of Meat People Butcher in Madison, Wisconsin, but it also means contamination can affect a much larger quantity of meat.

In 2014, for example, Wolverine Packing Company in Detroit, Michigan recalled 1.8 million pounds of ground beef products in connection with an E. coli outbreak that sickened 12 people, according to the Centers for Disease Control and Prevention (CDC) .

How to Safely Cook Beef

The good news is that cooking beef to a safe internal temperature can kill harmful bacteria and significantly reduce your risk of foodborne illness. The USDA recommends different minimum internal temperatures for steak and ground beef. For intact steaks, the recommended temperature is at least 145°F (63°C), followed by a rest of at least three minutes. For ground beef, the USDA recommends an internal temperature of 160°F (71°C) to kill harmful bacteria that may be present throughout the meat.

Determining whether beef has reached a safe internal temperature, however, requires more than slicing into it and judging based on its color. As food scientist Abbey Thiel , PhD, explains, the color of cooked beef can vary depending on factors such as oxygen exposure, making it an unreliable indicator of whether meat has reached a safe temperature.

You shouldn't rely on a recipe's cooking time alone, either. Phebus points out that factors such as how tightly you pack ground beef into a patty or meatloaf can affect how quickly it reaches the target temperature. "The only way that you can ensure safety during cooking, whether you're at home or whether you're in a restaurant, is to use a tip-sensitive thermometer and take internal temperatures," says Phebus. To check a burger's temperature, insert a thermometer through the side of the patty so the tip reaches its center.

But What If I Really Love My Burgers Rare?

The USDA's recommendations are intended to minimize the risk of foodborne illness, but some people may decide that eating a burger cooked to a lower temperature is worth the additional risk. "It's really a cost-benefit analysis, and that's an analysis everyone needs to make for themselves," says Megan O. Steintrager , associate editorial director at Serious Eats. "Personally, I'm willing to take the risks of eating over-easy eggs and raw oysters during "R" months , but I only eat rare burgers if I've ground the meat myself."

Grinding your own beef gives you more control over how the meat is handled, but it doesn't eliminate the risk of bacterial contamination or make rare burgers safe. And for people at greater risk of serious foodborne illness—including young children, adults 65 and older, pregnant people, and those with weakened immune systems—the consequences can be especially severe. Steintrager says she wouldn't serve undercooked burgers, runny eggs, or raw oysters to anyone in those groups.

Ultimately, how much risk you're willing to accept is a personal decision. But if minimizing the risk of foodborne illness is your priority, the safest course is to follow the USDA's recommendation and cook ground beef to an internal temperature of 160°F (71°C).

Read the original article on Serious Eats