The pathogen that prompted those concerns, Cronobacter sakazakii, can be widely found in the environment -- but in infants, it can be deadly.
Yet within the last five years, those companies -- Reckitt's Mead Johnson, Gerber, and Perrigo's PBM -- have also not been immune to operational and even contamination-related concerns. ABC News has reviewed FDA inspection documents for the three other domestic companies which, along with Abbott, have been responsible for roughly 90% of the country's formula market.
FDA investigators said that company records indicated Cronobacter was found in one of the plant's rooms, and that the area was subsequently sanitized. A plant operator was observed not washing his hands between glove changes, and not changing his gloves between touching non-food and food contact surfaces.
The potential problems the FDA discovered at the plant were addressed in time for later inspections -- but food safety experts told ABC News these issues can become a serious problem if not immediately dealt with. The Zeeland facility submitted a corrective action plan, promising "increased frequency of cleaning the areas where positive results were identified, evaluation and inspection of equipment" and "repairs to equipment and the facility as needed."
Reckitt said they "regularly review and enhance" their facilities' manufacturing processes "and invest in new technologies and equipment," adding that their "robust operating protocols meet or exceed the highest regulatory standards," which they employed while "safely" increasing infant formula amid the shortage.
"We are most interested in how aggressively a firm addresses and responds to potential contamination," the FDA spokesperson said. Lynn said that FDA investigators did what they were supposed to do: identify deficiencies for the companies to fix. A Gerber spokesperson told ABC News that their infant formulas go through up to 500 quality and safety checks, "many of which are above and beyond regulatory requirements."