Before firing up the grill this weekend, you may want to know more about the beef.
Just in time for Fourth of July barbecues, concerns about E. coli-tainted beef are again plaguing the U.S. Department of Agriculture's Food Safety and Inspection Service.
"Safe food handling is always important, but during peak grilling season in the warm summer months, there needs to be an increased awareness of safe food handling practices," Agriculture Secretary Tom Vilsack said today.
The latest voluntary beef recall came from JBS Swift Beef Company, which expanded its recall "out of an abundance of caution for consumers." The company is calling its customers and sending out letters to alert them to the recall.
"It is important for consumers to note that the recalled product from the date in question was sold by JBS as whole muscle cuts, not as ground beef," company spokesman Chandler Keys said Sunday. "The ground beef that might have been associated with illness was produced by other companies who often do not use the antimicrobial intervention steps we employ in our facility to reduce the risk of the beef products."
Ground beef is typically cause for more concern than steak because the inside and the outside of the product have been mixed together. Someone would need to pierce the skin of a steak for E. coli to get inside. That could happen if a meatpacker uses a needle to pump flavoring and tenderizer into meat.
"If you're grilling steaks, it's not the same level of concern," said Jeremy Russell, director of communications and government relations at the National Meat Association. "The steaks are going to be sterile on the insides as long as they haven't been tenderized."
But the question remains: Where did the more than 421,000 pounds of recalled beef products go from there? Food safety experts are not yet sure where the meat was shipped once it left the Greeley, Colo.-based plant -- nor what grocery stores and, ultimately, refrigerators it may have landed in.
That's exactly what a rule issued late last summer was designed to avoid. The rule requires the FSIS to publicize within 10 days a list of all stores where recalled meat and poultry may have been sold to shoppers.
But Bill Marler, an attorney focused on food poisoning cases with the Seattle-based law firm Marler Clark, said if the FSIS waits 10 days, the information would be of little help to consumers who have already prepared for the holiday weekend -- even if the FSIS is following the rule.
"It just seems inconceivable to me that they can't release this information more timely so people who have this in their refrigerator know what to do with it or know what not to do with it," Marler said.
"Whether they're absolutely following the rule or not, this is the kind of information that JBS Swift should have at their fingertips," he added.
Meantime, Russell said "of course" it's safe to eat meat this weekend. He said the industry's voluntary recall system is indeed effective and "it's very fast."
"They have an effective tracking mechanism. The challenge is that the products been consumed," Russell said. "We don't know what remains."
There are reports of about two dozen illnesses so far in several states that could be linked to the outbreak. Symptoms of E. coli include dehydration and bloody diarrhea. In serious cases, people can succumb to kidney failure.
The USDA is offering tips on how to safely handle raw meat to avoid getting sick from bacteria like E. coli:
Don't simply rely on the meat's color to make sure your food is ready. Instead use a thermometer and only eat ground beef or hamburgers that have been cooked to an internal temperature of 160 degrees F.
Refrigerate raw meat within two hours of purchasing, or one hour on hot days when it's more than 90 degrees F. Also refrigerate cooked meat within two hours of cooking it.
Wash hands for at least 20 seconds with hot, soapy water before and after handling raw meat. Do the same for cutting boards, dishes and utensils used to prepare the meal. Keep raw meat away from food that won't be cooked.
Shoppers concerned about the recall can call the company's hotline at (800) 685-6328.
They can also receive more information from the USDA's Food Safety and Inspection Service at AskKaren.gov, or by calling USDA's hotline at 888-674-6854.
A full list of recalled beef products is also available here.
Last Wednesday, JBS Swift announced it would voluntarily recall about 41,280 pounds of beef products -- such as intact cuts of beef, as well as boxes of beef used for steaks and possibly further processed somewhere else -- that were produced on April 21 and 22. The company said those products were shipped to distributors and stores in 13 states.
On Sunday the USDA's food safety arm announced an expansion of that recall , flagging another 380,000 pounds of beef products for possible E. coli contamination.
The expansion includes questionable beef that was shipped both within the United States and abroad.
But beef is just one of many foods causing concern. On Monday, the Food and Drug Administration, which monitors safety of all foods except for meat, poultry and eggs, which are overseen by the USDA, found E. coli at the plant that makes Nestle Toll House cookie dough.
The FDA has also struggled this year to trace foods including tainted peanuts and pistachios.
Earlier this summer, Illinois meatpacker Valley Meats LLC of Coal Valley recalled nearly 96,000 pounds of ground beef due to possible E. coli contamination.
Last summer Nebraska Beef Ltd. of Omaha recalled more than 5 million pounds of beef due to an E. coli outbreak shortly before the FSIS issued its rule.
Today, Marler's advice is to keep frozen meat in the freezer and to hold off on cooking meat until you have more information about where it came from.
"This whole secretiveness of food safety is why we have the problem to begin with," Marler said. "Things need to be transparent and the public needs to know what's risky and what's not."
ABC News' Brian Hartman contributed to this report.