Salmonella Bacteria, Backyard Chickens and Safer Eggs

According to the Center for Disease Control and Prevention, CDC, salmonella bacteria causes about 1.4 million cases of foodborne illness each year. Salmonella bacteria in eggs account for 80% of the salmonella enteritidis infections. Symptoms—fever, diarrhea, abdominal cramps, and headache—can last a few days but is often lasts longer and can lead to severe complications or death. Salmonella causes more deaths than any other foodborne bacteria. The salmonella bacteria entered the chicken population in the last fifty or sixty years. Chickens harbor the salmonella bacteria without any signs of illness, making it impossible to know which animals are infected, and pass Salmonella along to both the yolk and white while the egg is forming in the ovaries and future generations of chickens. It is impossible to tell by appearance which eggs might be infected, and though in truth only a tiny proportion of eggs are infected, millions of eggs are consumed each day.

Federal regulations require pasteurization of raw liquid egg products used in commercially sold dishes such as ice cream, eggnog, sauces and ceasar dressings, but raw eggs sold in the shell to consumers are not required to be pasteurized. Less than 0.5% of all shell eggs produced for retail sale in the United State is pasteurized, according to the U.S. Department of Agriculture, USDA. I take food safety very seriously since I feed not only my family every day, but I cook and host holiday celebrations and prepare food for community and group gatherings. A family tradition (and specialty) is homemade eggnog. It is made with raw eggs. The alcohol does not kill the salmonella bacteria, despite what bar tenders tell you. So, for approaching 20 years I have made the eggnog and other recipes using Davidson’s Pasteurized eggs now called “Safety Eggs.” I have not used these eggs exclusively because I find the texture of the whites is not quite right. When you use them in some recipes they do not rise properly without extra whisking, though I have managed with the help of my Kitchen Aid Mixmaster to beat dozens of the egg whites to soft peaks year after year.

From Davidson's web site

Now, however, researchers at the Princeton Plasma Physics Laboratory (PPPL) and the U.S. Department of Agriculture (USDA) have developed a new technique and device for rapidly pasteurizing eggs in the shell reportedly without changing the texture of the egg white. The new method uses radio frequency (RF) energy to transmit heat through the shell and into the yolk while the egg rotates. While the yolk is heating cool water flows over the rotating egg to protect the white which is more sensitive to heat than the yolk. The RF energy creates an electric current that produces heat inside the egg. The egg is then bathed in hot water to pasteurize the white and finish pasteurizing the yolk.

The team lead by David Geveke from the USDA and Christopher Brunkhorst PPPL engineer, believes they have produced a pasteurized egg that is hardly discernible from a fresh, non-pasteurized egg. The USDA Agricultural Research Service in Wyndmoor, Pa. teamed up with PPPL engineer Christopher Brunkhorst, an expert in RF heating, to develop the method and device. The prototype can pasteurize shell eggs in about one-third of the time that current methods require. Current methods place the eggs in heated water for about an hour and change the consistency of the egg white. The RF process reportedly maintains the egg white's transparency and texture. The USDA has applied to patent the prototype design which, delivers RF energy through the shell by placing electrodes against opposite sides of the egg. The egg rests on rollers that turn it to distribute the cooling and heating water evenly.

Egg safety affects all of us. Remember, salmonella is not just a disease of commercial chickens. It's common these days for chickens, ducks, and other poultry to carry Salmonella. Live poultry kept as pets or to provide fresh eggs may harbor the salmonella bacteria. Salmonella bacteria live in the intestines of poultry and many other animals. Even organically fed poultry raised in a home setting can have Salmonella, because they were born with it. Live poultry can shed Salmonella bacteria in their droppings and from their bodies (feathers, feet, and beaks) even when they appear healthy and clean. The germs can also get on cages, coops, feed and water dishes, hay, plants, and soil in the area where the birds live and roam and can be picked up by children or adults who work or play where they live and roam. 

from CDC web site

Recently, a national outbreak of salmonella has been linked to an eastern New Mexico hatchery that sells live baby chickens, ducks and other poultry by mail and direct supply. New Mexico’s Department of Health said a strain of salmonella that's infected more than 300 people in 37 states was found in a duck pen at Privett Hatchery in Portales. According to the New Mexico Department of Health news release, salmonella infection is especially risky when parents keep the baby birds inside the house and allow their small children to handle and snuggle with them. Other cases can occur when parents don’t wash their hands properly after handling the birds, indirectly giving the infection to their children. Remember, these are backyard poultry.