Nearly a month after the Food and Drug Administration (FDA) issued an initial recall of eggs produced by a Wisconsin-based farm, the agency has upgraded its recall to Class 1, its highest categorization.

A Class 1 recall is defined as a "situation in which there is a reasonable probability that the use of or exposure to a violative product will cause serious adverse health consequences or death," according to the FDA.

On Sept. 6, Milo's Poultry Farms, LLC. of Bonduel, Wisconsin, recalled all "Milo's Poultry Farms" and "Tony's Fresh Market" branded eggs because they "have the potential to be contaminated with Salmonella, an organism which can cause serious and sometimes fatal infections in young children, frail or elderly people and others with weakened immune systems." The eggs were distributed in Wisconsin, Illinois, and Michigan via retail stores and food service distributors, a company announcement specified.

A total of 65 people were infected with Salmonella linked to the outbreak, per the initial recall. The illnesses spanned across nine states, including Wisconsin, Illinois, Michigan, Minnesota, Iowa, Virginia, Colorado, Utah and California. Twenty-four individuals have been hospitalized. No deaths have been reported.

The recall was officially bumped to a Class 1 on Sept. 30. The Associated Press reported that the recall includes more than 345,417 dozen cartons of eggs, which totals to approximately four million eggs.

The Centers for Disease Control and Prevention (CDC) has advised consumers who recently purchased the recalled eggs to throw them away or return them to their place of purchase. Surfaces, utensils and household items that may have come in contact with the eggs should be washed with hot soapy water or a dishwasher.

Consumers who are exhibiting any severe Salmonella symptoms -- like bloody diarrhea, excessive vomiting or dehydration -- should contact their healthcare provider immediately.