Pepperidge Farm is voluntarilyover possible contamination. The company told CBS News only four varieties may be tainted and no confirmed illnesses have been reported.
Mondelez International also issuedbecause of the same concerns over salmonella. The FDA says it is investigating and there is no evidence these products are contaminated.
The ingredient which may be contaminated with the bacteria is the whey powder in the seasoning.
Michael Moss, an investigative journalist who won a Pulitzer Prize for his reporting on contaminated food, joined "CBS This Morning" Wednesday. He says whey is a liquid byproduct from making cheese and Greek yogurt.
"They turn it into a powder which is something of a miracle ingredient for these companies," Moss says. "The taste, the protein, it helps the texture, it holds things together."
Moss says the problem comes when water or a contaminate, like salmonella itself, is introduced to a factory producing whey. That can create an issue for the company using that whey as an ingredient.
"The companies need to be more diligent about inspecting their suppliers because they're using this global food chain of ingredients over which they don't have enough control," Moss says. "They need to know who their suppliers are and they need to personally go in and check when there's a problem like this."
But Moss says the multiple companies involved in that food chain make it harder to pinpoint where the contaminate may have been introduced.
"Middle men get in the middle and they'll assemble things together and then sell them to the big food giants," Moss says. "So it's a complex problem."
What happens when people get sick from their food also makes tracing a contaminate difficult.
"A million people are getting sick from food every year, but very few of them find out what it is they ate because the symptoms can come 72 hours later," Moss says. "You go to the doctor and the doctor goes, 'what did you eat?' and that's the end of the story."
Moss says there could be several reasons for the recent increase in recalls, including investigators doing a better job catching problems and companies doing more diligence in reporting problems. But he feels this is not a new normal.
"These are rare incidents that we're hoping to see decline steadily over the years and not go up."