Over half a billion eggs have now been recalled so far in the United States since the recent salmonella outbreak. On Friday the ban was extended to include another Iowa farm. Environmentalists are saying that factory conditions are to blame. The salmonella outbreak has made more than 1,000 people sick and the number of people sickened will only be increasing.

After laboratory tests confirmed the eggs were tainted with salmonella, Iowa’s Hillandale Farms said that it would be recalling more than 170 million eggs. The latest recall puts the total number of potentially tainted eggs at about 550 million.

Egg supplier Wright County Egg has issued an egg recall in the states of Colorado, California and Minnesota, suspected being behind a recent spike in salmonella poisonings. The Centers for Disease Control and Prevention averages around 50 reports of salmonella cases each week, but in the last few months, the agency has been getting about 200 cases a week. Eggs that bear the name Lucerne, Albertsons, Mountain Dairy, Ralph’s, Boomsma’s, Sunshine, Hillandale, Trafficanda, Farm Fresh, Shoreland, Lund, Dutch Farms and Kemps are all from the Wright County Egg supplier.

If you’ve had eggs recently, watch for symptoms of salmonella poisoning, which include fever, diarrhea and abdominal cramping that tend to develop approximately 12 – 72 hours after ingesting the contaminated food. Most people recover on their own without any help from a doctor, though infants and the elderly are at risk and should seek immediate medical risk. Also, if you are of good health and think you may have salmonella poisoning, you are still advised to seek medical help so the outbreak can be documented properly. Most people recover within four to seven days.