Salmonella and Eggs

Eggs are one of nature’s most nutritious and economical foods. But it’s important that you take care when handling and preparing fresh eggs and egg products.

The inside of eggs that appear normal can contain a germ called Salmonella that can make you sick, especially if you eat raw or lightly cooked eggs. Eggs are safe when you cook and handle them properly.

How can I reduce my chance of getting a Salmonella infection?

  • Consider buying and using pasteurized eggs and egg products, which are widely available.
  • Keep eggs refrigerated at 40°F (4°C) or colder at all times. Only buy eggs from stores and suppliers that keep them refrigerated.
  • Discard cracked or dirty eggs.

Poultry may carry bacteria such as Salmonella, which can contaminate the inside of eggs before the shells are formed. Egg shells may become contaminated with Salmonella from poultry droppings (poop) or the area where they are laid.

  • Cook eggs until both the yolk and white are firm. Egg dishes should be cooked to an internal temperature of 160°F (71°C) or hotter.
  • Make sure that foods that contain raw or lightly cooked eggs, such as hollandaise sauce, Caesar salad dressing, and tiramisu, are made only with pasteurized eggs.
  • Eat or refrigerate eggs and foods containing eggs promptly after cooking. Do not keep eggs or foods made with eggs warm or at room temperature for more than 2 hours, or 1 hour if the temperature is 90°F or hotter.
  • Wash hands and items that came into contact with raw eggs—including counter tops, utensils, dishes, and cutting boards—with soap and water.

Illness from Salmonella can be serious and is more dangerous for certain people.

Adults older than 65 years, children younger than 5 years, and people with weakened immune systems, such as those with HIV/AIDS, diabetes, or an organ transplant, may get a more serious illness that can even be life threatening.

In most cases, illness lasts 4–7 days and people recover without antibiotic treatment. Symptoms include:

  • Diarrhea
  • Vomiting
  • Fever
  • Abdominal cramps

Symptoms typically appear 6 to 48 hours after eating a contaminated food, though this period is sometimes much longer. Some people can have diarrhea many times a day for several days and the sick person may need to be hospitalized.

Should I see the doctor?

Call your child’s doctor if your child has:

  • Diarrhea that doesn’t improve after 1 day
  • Vomiting lasting more than 12 hours for infants, 1 day for children younger than age 2, or 2 days for other children
  • Signs of dehydration, including not urinating in 3 or more hours, dry mouth or tongue, or cries without tears
  • Fever higher than 102˚F (39˚C)
  • Bloody stools

Call your doctor if you have:

  • Diarrhea that doesn’t improve after 2 days
  • Vomiting lasting more than 2 days
  • Signs of dehydration, including little or no urination, excessive thirst, a very dry mouth, dizziness or lightheadedness, or very dark urine
  • Fever higher than 102˚F (39˚C)
  • Bloody stools

Source: U.S. Department of Health & Human Services

Bagged Salads and Salmonella

A new study from the University of Leicester shows that small amounts of damage to salad leaves in bagged salads encourage the presence of Salmonella enterica. Juices released from damaged leaves also enhance the pathogen’s ability to attach to the salad’s plastic container. The research is published November 18th in Applied and Environmental Microbiology, a journal of the American Society for Microbiology.

In the study, salad juices in water—to mimic the grocery salad bag environment—more than doubled motility, or movement of individual Salmonella bacteria, abetting salad leaf colonization. In the course of a typical five day refrigeration storage time around 100 Salmonella bacteria multiplied to approximately 100,000 individual bacteria. Salad juices also boosted formation of biofilms on salad leaves. Microbial biofilms generally cling tenaciously to the surfaces they coat—medical implants, stainless steel, or one’s teeth, in the form of dental plaque—and Salmonella biofilms on salad leaves are no exception. They are powerfully resistant to being washed off.

Yet surprisingly, the normal microbial flora on salad leaves did not respond to leaf juices, suggesting that the leaf juices give Salmonella a marked advantage in colonizing salad leaves as compared to competing bacteria, according to the report.

Salad leaf crops are usually grown in open fields where they can be exposed to Salmonella, via insects, bird poop, and manure, among other sources. While outbreaks of Salmonellosis due to such contamination are uncommon, they are nonetheless a public health problem. Such outbreaks may occur despite practices used to mitigate the problem, such as irrigation with clean water, good hygiene, leaf washing, and the like, said coauthor Primrose Freestone, PhD, Associate Professor in Clinical Microbiology, University of Leicester, UK. In fact, salad leaves can acquire Salmonella from recycled wash water, she said.

Moreover, earlier studies have shown that Salmonella are so powerfully attracted to salad leaf and root juices that they can find their way into the plant vasculature during the salad plant’s germination, and once inside, there is no way to wash them out, said Freestone.

Salmonella grows especially well on spinach, said Freestone. “”It seems the pathogen prefers spinach.”

Pre-prepared salads are sold increasingly commonly in grocery stores, said Freestone. They also appear in fast food and in airline meals. However, few studies had previously investigated the behavior of Salmonella within ready-to-eat bagged salad, she said. “We wanted to investigate what happens to Salmonella in a bag of salad to better understand the potential risks to consumers and inform future research on reducing attachment of this pathogen to salad leaves. This study is part of our ongoing research into ways to reduce the risk of Salmonella persisting and growing when it is present in bagged salad.”

Source: American Society For Microbiology