SEP 21, 2016 10:56 AM PDT

Smaller flocks, more Salmonella

WRITTEN BY: Kerry Evans
I like eggs - scrambled, fried, poached, you name it. What I don’t like is Salmonella. A new study from Pennsylvania State University found that eggs from small flocks are more likely to be contaminated with Salmonella than eggs from large commercial flocks.
Chicken eggs can contain Salmonella.
Salmonella enteritidis causes egg-associated Salmonellosis. S. enteritidis is a rod-shaped Gram-negative bacterium. Egg-eating humans can become infected with these bacteria in a couple of different ways. First, the outsides of eggs can be contaminated with chicken fecal matter. Salmonella is part of a chicken’s normal gut flora, so it’s easy for eggs to become contaminated. Luckily, strict rules about sanitizing the eggs have eliminated this as a point of infection (for the most part).

On the other hand, a chicken’s ovaries can become infected with Salmonella. When this happens, Salmonella can find its way inside of the eggs (a Trojan horse, if you will). This is why it’s especially important to cook your eggs thoroughly, ensuring that any bacteria are destroyed.

The Penn State researchers wanted to know how the safety of eggs from large flocks compared to eggs from small flocks. Over a period of 6 months, they purchased eggs from 240 farmers’ markets or roadside stands from across 67 counties in Pennsylvania. Then, they sampled the outsides and insides of the eggs for Salmonella.

What they found was surprising - 2% of the eggs tested positive for S. enteritidis. This is a higher incidence of contamination than is seen with large commercial flocks. Of the 5 contaminated eggs, only 1 had S. enteritidis on its outer shell. Bacteria were found inside the other 4 eggs, indicating that these chickens had ovarian infections.

According to study author Subhashinie Kariyawasam, "We were curious about Salmonella contamination of eggs produced by these flocks because the prevalence of this pathogen in smaller flocks was not known. Now we know that the prevalence of Salmonella enteritidis in eggs produced by small flocks is higher than in eggs produced by larger flocks."

What’s the take-home message? Cook your eggs thoroughly - small flocks aren’t subject to federal regulations like the FDA Final Egg rule. “If you buy your eggs from the small producers”, says Kariyawasam, “you need to worry about Salmonella just as if you bought eggs produced by large flocks. And, beyond the consumption of eggs, birds in these flocks can have Salmonella, so people with backyard poultry need to be aware of the dangers with pet birds - there is a risk to allowing birds to come into the house and children playing with the chickens.”
Sources: Science Daily, Medicine Net
About the Author
  • Kerry received a doctorate in microbiology from the University of Arkansas for Medical Sciences.
You May Also Like
OCT 21, 2019
Cancer
OCT 21, 2019
Self-Destructing Cancer: Study Stops Chain Reaction of Tumor Growth
A new study reveals that stopping one protein from functioning can cause some cancer cells to die from stress....
OCT 21, 2019
Genetics & Genomics
OCT 21, 2019
A Pathogen That Has Evolved to Spread in Hospitals
Clostridium difficile is the primary cause of infections that are acquired in hospital settings; it causes diarrhea and intestinal inflammation....
OCT 21, 2019
Health & Medicine
OCT 21, 2019
Acute Flaccid Myelitis and Its Association With Enterovirus D68
Acute flaccid myelitis (AFM), a polio-like infection, caught the attention of physicians in the U.S. during late summer and early fall in 2014. The outbrea...
OCT 21, 2019
Microbiology
OCT 21, 2019
Antidepressants and Serotonin Impact Gut Microbiota
About 90% of the serotonin found in the human body is made in the gut. Some bacteria can encourage the release of serotonin from gut cells....
OCT 21, 2019
Microbiology
OCT 21, 2019
Potential New Antibiotic Discovered in Soil-Dwelling Microbe
Many of our best antibiotics have come from microbes, which have to use them to battle other microorganisms in a struggle for resources....
OCT 21, 2019
Microbiology
OCT 21, 2019
Early Ancestor of Animals Can Group Together and Coordinate Their Movements
After observing unusual microorganisms that had been collected in Curaçao, researchers saw a strange thing....
Loading Comments...