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USDA Develops New Egg Pasteurization Technology that Kills 99.999% of Salmonella Bacteria

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Researchers at the U.S. Department of Agriculture’s (USDA) Agricultural Research Service have developed a new egg pasteurization technology that can quickly kill 99.999% of Salmonella bacteria in intact shell eggs.

Most Eggs Are Not Pasteurized

Most eggs are not pasteurized. In fact, less than 3 percent of commercially produced eggs in the United States undergo this treatment.

This is the reason eggs have such strong safety recommendations. It is also the reason you should not consume them unless they are fully cooked or eat raw doughs that contain them.

Why is there such a strong stance on pasteurized milk, but raw eggs are ok? Especially with the significant Salmonella risk associated with the food.

Mostly – time and money. Which in a sense is the exact same thing.

The pasteurization process is time consuming process.

Conventional Egg Pasteurization Procedure

The conventional egg pasteurization procedure for in-shell eggs is a thermal process. Not unlike the milk pasteurization process. It requires the egg to be heated and can take nearly an hour per batch.

The egg must be fully submerged in hot water and heated to an appropriate temperature. The most common temperature vs time combination is 57 °C (135°F) for 57.5 minutes. This achieves effective deactivation of Salmonella while retaining quality.

Radio Frequency Egg Pasteurization Procedure

The USDA’s new egg pasteurization technology involves Radio Frequency (RF). This methodology provides the same result in a fraction of the time compared to conventional egg pasteurization processes.

This method still uses heat. Just in a novel way.

When RF treatment is applied, water molecules inside an egg rotate and align with the RF instrument’s electric field. This produces molecular friction that rapidly heats the liquid inside the egg’s shell.

According to reports, this new RF egg pasteurization technology can claim 99.999% efficacy against Salmonella bacteria in as little as little as 24 minutes. This is about half the time of conventional egg pasteurization methods.

In a study performed using this RF egg pasteurization technique, RF-processed eggs continued to have undetectable levels of Salmonella bacteria after seven days at 7 °C storage. A temperature that simulates cold chain conditions.

Almost as important, the quality of the eggs did not diminish due to RF processing.

Why Are Eggs So Risky?

Salmonella bacteria and eggs are like thunder and lightning. If you see one, the other is likely on its way.

But why?

To answer that question, you must answer another age-old question.

Which came first? The chicken? Or the egg?

In this case, the chicken lays the egg. So. Now that this question is settled, we can move on to the more important question of what is the secret of life? 42 of course.

Enough of that. Back to eggs.

Chicken Anatomy

Approximately every 25.5 hours a chicken has internally assembled an egg, ready to go. When the timer goes “ding” and she lays the egg, it exits the body through the same passageway that feces is excreted. Inevitably, even if trace amounts, a bit of chicken poop will transfer to the egg’s shell.

This is the source of all chicken egg woes, as chicken poop has a high probability of containing Salmonella bacteria.

Does this make the chicken sick? Fortunately, no. Salmonella does not cause illness in chickens. It does, however, cause illness in humans.

Shell Eggs Require Washing

Commercial eggs with a USDA seal must be washed at the processing plant. This helps to remove any feces and bacteria that may be on the egg. Most large-volume egg processors go one step further, adding a sanitizing rinse as well.

If Eggs are Washed, Why is Egg Pasteurization Needed?

You may be thinking, if the eggs are washed and even sanitized, what is the problem. Unfortunately, simply washing the egg is not a guarantee it will be Salmonella-free.

Eggs are porous. Salmonella bacteria can make their way inside the pores in the egg shells after they’re laid. Additionally, these bacteria may be present inside the hen’s reproductive tract, enabling Salmonella to enter the egg from the inside.

Whether the bacteria come through the pores of the shell or from inside the chicken, Salmonella may be found in both the yolk and the egg whites. For this reason, both the yellow and white parts of the egg should be fully cooked to ensure safety.

Who Is At Greater Risk For Eating Raw or Undercooked Unpasteurized Eggs?

No one should eat foods containing raw eggs, regardless of risk factor. There are, however, certain people that are more vulnerable to foodborne illness and should absolutely never consume raw or under cooked eggs.

These “at risk” people include:

  • Infants
  • Young children
  • Older adults
  • Pregnant people
  • Those with a weakened immune system
  • Those with a chronic illness

What is Salmonella, and How Bad Is It?

Salmonella is the name of a group of bacteria that is a common cause of foodborne illness in the United States. Chicken and eggs are common vectors, but Salmonella can contaminate any number of foods. From leafy greens to lunch meats, and everything in between.

Common symptoms of Salmonella infection include diarrhea, fever, and abdominal cramps. These symptoms usually begin around 12 to 72 hours after consuming a contaminated food and last about a week (4 to 7 days).

Most people recover without specialized treatment. In fact, most people will not be given antibiotic treatment, even if they do seek medical attention. The exception being those in the “at risk” category above.

These people are at greater risk for infection after exposure as well as more severe symptoms.

Salmonella Complications

In some cases, diarrhea symptoms may become so severe that it causes extreme dehydration. In these cases, hospitalization may be required.

Other complications arise when the bacteria leave the digestive system and enter the bloodstream. In this way, the bacteria can affect other areas of the body. Arterial infections (i.e., infected aneurysms), endocarditis, reactive arthritis (includes symptoms such as joint pain, eye irritation, and/or pain during urination – all of which can last for months or even years), and irregular bowel habits.

Egg Pasteurization Can Reduce Salmonella Infection

Whether conventional or through new RF technology, egg pasteurization makes this high-risk food safter. Scientists continue to research capabilities for this RF technology and others that can take faster pasteurization to commercial applications.

With only 3% of eggs pasteurized, we can do better than that!

Want to Know More About Food Safety?

If you’d like to know more about food safety in the news, like Radio Frequency Egg Pasteuriztion, check out the Make Food Safe Blog. We regularly update trending topics, foodborne infections in the news, recalls, and more! Stay tuned for quality information to help keep your family safe, while The Lange Law Firm, PLLC strives to Make Food Safe!

By: Heather Van Tassell (contributing writer, non-lawyer)

Heather Van Tassell

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