WASHINGTON, Aug 23: A massive recall of eggs possibly tainted with salmonella bacteria is now at more than half-a-billion and could grow, the top US food safety official said on Monday.

“It is the largest egg recall that we've had in recent history,” Margaret Hamburg, head of the US Food and Drug Administration (FDA), told NBC television.

“We may see some additional recalls over the next couple days, even weeks, as we better understand the network of distribution of these eggs contaminated,” she said.

Hamburg added that US officials were “continuing to investigate aggressively to determine the exact source of the contamination as we move forward with the recall.”

There are no known salmonella deaths due to the eggs, but health officials said the outbreak has sickened hundreds of people across the United States.

The recalls affect two chicken egg processors -- Hillandale Farms and Wright County Eggs, both in the midwestern state of Iowa -- and cover at least 14 US states, from California to Arkansas.

The US Centers for Disease Control and Prevention (CDC) has warned that the outbreak could actually be larger than reported, because most people who get sick from salmonella do not seek medical treatment. —AFP