NEW YORK (CNN) -- Topps Meat Co. on Saturday expanded a recall of ground beef from about 300,000 pounds to 21.7 million pounds, one of the largest meat recalls in U.S. history.

The recalled products are all ground beef patties with various brand names.

In a statement, the Elizabeth, New Jersey, company said the hamburger patties may be contaminated with E. coli O157:H7, a bacterium that can cause severe diarrhea and cramps, as well as other complications.

A statement from the U.S. Department of Agriculture said 25 illnesses are under investigation in Connecticut, Florida, Indiana, Maine, New Jersey, New York, Ohio and Pennsylvania.

The ground beef products being recalled have a "sell by date" or a "best if used by date" between September 25, 2007, and September 25, 2008, Topps' statement said. Watch the latest on the beef recall »

The packages also have the marking "Est. 9748" inside the USDA mark of inspection.

Tuesday, the company announced a recall of about 331,000 pounds of hamburger meat, according to the USDA.

"Because the health and safety of our consumers is our top priority, we are taking these expansive measures," said Vice President of Operations Geoffrey Livermore in the statement.

"Topps is continuing to work with the USDA, state departments of health, retailers and distributors to ensure the safety of our consumers. Additionally, we have augmented our internal quality control procedures with microbiologists and food safety experts. We sincerely regret any inconvenience and concerns this may cause our consumers," Livermore said.

Don't Miss List of recalled products

This is the company's first recall in its 65 years of business, the statement said.

Consumers who find the products at home are asked to cut off the UPC code and return it to Topps for a full refund, then dispose of the product immediately, Topps spokeswoman Michelle Williams said.

The company said to avoid E. coli, consumers should wash hands thoroughly after handling the beef.

Topps set up a toll-free recall help line at (888) 734-0451.

Williams said because the products may have been produced up to a year ago, many of them have already been safely consumed.

Production in the ground beef area of the company's plant in Elizabeth has been shut down until all the investigations are complete, Williams said in a phone interview.

"We're working with the USDA and the CDC [Centers for Disease Control and Prevention] and conducting our own investigation," she added.

The products, all ground beef patties and hamburgers with various brand names, were distributed mainly in the northeastern United States, but went to retailers in many other areas of the country as well, Williams said.

While the sheer size of the recall is large, two other companies have been involved in larger recalls.

In 2002, Pilgrim's Pride recalled more than 27 million pounds of poultry, and Hudson Foods recalled 25 million pounds of ground beef in 1997. E-mail to a friend

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