Salmonella (cont.)

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What are the unique situations that allow Salmonella to contaminate eggs?

Although eggs have been known to occasionally transmit Salmonella bacteria to humans, there have been outbreaks in the last few years involving egg production plants. In the summer of 2010, an extremely large egg recall due to mainly Salmonella enteritidis contamination caused about 1,500 people to become ill. As a result, the FDA recalled over 500 million eggs.

What is unique about the 2010 Salmonella disease outbreak is that it is related to the "modern egg farming" situation found in many industrialized countries and how Salmonella is transmitted in domestic hens to their eggs.

Salmonella is reportedly transmitted in hens in at least three ways:

  1. Direct surface contamination of eggs by contact with Salmonella-contaminated feed, feces, and cage material
  2. Salmonella organisms transferred from hen ovaries to the yolk before the shell is formed in the hen's body
  3. After the egg is laid and its surface contaminated with Salmonella, some of the bacteria reportedly can penetrate the shell and migrate to the yolk.

Unfortunately, "modern egg farming" techniques that are practiced by some producers augment Salmonella transfer to eggs by practicing techniques that result in massive egg production in extremely poor sanitary conditions for the hens. Once a "farm factory" gets Salmonella contamination, most of the hens and many of their eggs become contaminated. This cross-contamination in egg-producing facilities is usually due to lack of sanitary facilities and poor housing conditions for the hens. Many times, egg-producing hens are contaminated from outside sources, such as cattle feces and rodent feces due to poor quality control in feed and hen cage conditions. Currently, the FDA (and even the FBI) have looked into this egg recall to help determine if some producers have been negligent, especially in the housing methods used for poultry.

The two main producers under investigation are Hillandale Farms and Wright County Farms. However, eggs from these farms have been sold to at least 16 different suppliers. In industrialized countries, mass production techniques that make food readily available can also spread disease rapidly to many people. Vigilance by quality-control agencies and people who purchase foods (in this case, eggs) from bulk suppliers needs to be constant. The FDA suggests that if people are not sure if they have contaminated eggs, they should simply dispose of the eggs. Even in times when there are no recalls, people are advised to thoroughly cook items such as eggs and meat (especially hamburger meat) and drink from treated water sources. Other fluids need to be adequately pasteurized (heat-treated to reduce or eliminate pathogens) or sterilized. The FDA publishes its list of product recalls on the Internet and the site is frequently updated; the following web site, http://www.fda.gov/Safety/Recalls/default.htm will allow individuals to check on specific products and how to identify them.


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