According to the 21st Century Business Herald APP, the Centers for Disease Control and Prevention (CDC) in the USA stated on Wednesday that mcdonald's (MCD.US) Quarter Pounder and onion slices on other menus may be the source of the E. coli outbreak that has sickened 90 people.

The epidemic related to this burger was first reported on October 22, and thinly sliced onions are suspected as the source of infection.

The FDA and the company have confirmed that Taylor Farms is the supplier in the affected area and has recalled several batches of yellow onions produced at their factory in Colorado.

The FDA announced on Wednesday that inspections have started at Taylor Farms processing center in Colorado, where 29 people in the state have fallen ill due to the outbreak.

The FDA added that an onion grower in Washington state is also under investigation.

The CDC reported that the number of infections has risen by 15 people from the previous 75, with 27 people hospitalized for the illness, and one fatality has occurred.

Last Sunday, the company and the Colorado Department of Agriculture also ruled out the possibility that beef patties were the source of the epidemic.

The E. coli O157:H7 strain that caused the McDonald's outbreak could lead to 'very serious illnesses', especially in older adults, children, and those with weakened immune systems.

The FDA pointed out that symptoms can appear from a few days to 9 days after consuming contaminated food.

As of October 30, the epidemic has affected Colorado, Kansas, Utah, Wyoming, Iowa, Missouri, Montana, Nebraska, New Mexico, Oregon, Wisconsin, Washington, and Michigan.

North Coast Research analyst Jim Sanderson said, 'It can be said at least that the more cases like this appear in the news, the more difficult it will be for McDonald's to readjust.'

McDonald's said it will resume selling 4-ounce beef burgers this week, with one-fifth of the affected restaurants in 0.014 million restaurants in the USA temporarily removing this burger from the menu.

On Tuesday, McDonald's executives did not address the potential impact of this incident on sales. CEO Chris Kempczinski apologized to customers, adding that he is 'confident in the safety of dining at McDonald's'.