Salmonella is a type of bacteria that can cause food poisoning. Salmonella is found on the shell and inside the egg. The most common types of salmonella in egg is s. enteritidis. Washing eggs can remove salmonella from shells but the bacteria is still found inside the eggs.

It is estimated that there is salmonella found inside in 1 in 20,000 eggs and 1% of eggs have salmonella on the shell. But because of mixing and cross contamination, the risk is greater than consuming a single egg.

Salmonella can primarily gets into chicken eggs in 1 of  2 ways. If a hen is infected with Salmonella, the bacteria can get into the egg as it is forming in the oviduct. The other way is if the egg is laid or falls on a contaminated surface such as feces or bedding material, or if the eggshell is contaminated after it is laid. A hen with a salmonella infection can lay eggs without appearing sick.

Without lab equipment, you can’t – an egg contaminated with salmonella will likely look, taste and smell just like any other egg.

Cooking eggs to an internal temperature of 165F can kill salmonella. This means both whites and yolk are firm. However many of the most popular egg styles do not reach this temperature, including sunny side up, poached and soft boiled. Many baking and culinary techniques require using eggs that are under-cooked and therefore present a risk of contaminating a dish. Other examples where raw or undercooked eggs are used are eggnog, Caesar dressing, flan, mouses, cookie dough, salad dressings and cocktails. Again, the risk is direct consumption and cross contamination.

Salmonella can grow rapidly under the right conditions, with a colony doubling in size every 20 minutes.

What are the consequences of a salmonella infection?

Eggs that are contaminated with salmonella can lead to serious infection, illness, long term health effects and sometimes death.  According to the CDC:

• Most people who get sick from Salmonella have diarrhea, fever, and stomach cramps.
• Symptoms usually begin 6 hours to 6 days after infection and last 4 to 7 days. People with diarrhea should drink extra fluids.
• Most people recover without specific treatment and should not take antibiotics. Antibiotics are typically used only to treat people who have, or are at risk for, severe illness. Rarely, Salmonella spreads to the bloodstream and causes a life-threatening infection.
• Some groups of people are more likely to get infected and get seriously ill. These groups include children younger than 5 years, adults 65 years and older, and people who have health problems or take medicines that lower the body’s ability to fight germs and sickness (weakened immune system).