Last week's recall of 21.7 million pounds of Topps Meat frozen hamburger, which the U.S. Department of Agriculture has linked to 27 reported and three confirmed illnesses, comes three months after 5.7 million pounds of ground beef were recalled for E. coli-related reasons, USA Today reported Tuesday.

The American Meat Institute said a slight rise has been recorded in positive E. coli tests by the U.S. government over the summer.

"It's caused us to pause," Randy Huffman, vice president of the AMI Foundation, said to the newspaper. "We've redoubled our efforts and focused on the things that work."

The rate of positive E. coli tests has shrunk by 73 percent since 2000 but an increase was recorded in 2007 when compared with the preceding three years.

"Something has changed and it has not changed for the better," Bill Marler, a prominent E. coli plaintiff's attorney, told USA Today.

However, Huffman said the rise could be the result of a "random event."