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Other Questions

Choose a topic below to answer any other concerns.

How can I tell if my eggs have spoiled?

The faster you use your eggs, the less time any potential bacteria will have to multiply. However, when properly handled and stored, eggs rarely spoil. Instead, as an egg ages, the white becomes thinner, the yolk becomes flatter and the yolk membrane weakens. Although these changes may affect appearance, they don’t indicate spoilage and don’t have any great effect on the nutritional quality of the egg or its functions in recipes. Rather than spoiling, if you keep eggs long enough, they’re more likely to simply dry up – especially if they’re stored in a moisture-robbing, frost-free refrigerator.

But, like all natural organic matter, eggs can eventually spoil through the action of spoilage organisms. Although they’re unpleasant, spoilage organisms don’t cause foodborne illness. The bacteria Streptococcus, Staphylococcus, Micrococcus and Bacillus may be found on egg shell surfaces because all these species can tolerate dry conditions. As the egg ages, though, these bacteria decline and are replaced by spoilage bacteria, such as coliform and Flavobacterium, but the most common are several types of Pseudomonas. Pseudomonas can grow at temperatures just above refrigeration and below room temperatures and, if they’re present in large numbers, may give eggs a sour or fruity odor and a blue-green coloring.

Although it is more likely for bacteria to cause spoilage during storage, mold growth can occur under very humid storage conditions or if eggs are washed in dirty water. Molds such as Penicillium, Alternaria and Rhizopus may be visible as spots on the shell and can penetrate the shell to reach the egg.

Discard any eggs with shells – or, for hard-boiled eggs, egg white surfaces – that don’t look or feel clean, normally colored and dry. A slimy feel can indicate bacterial growth and, regardless of color, powdery spots that come off on your hand may indicate mold.

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Are there hormones in my eggs?

Whether it says so on the carton or not, laying hens (hens raised to produce eggs) do not receive hormones in any form.

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Do antibiotics in eggs contribute to antibiotic resistance?

Antibiotics aren’t considered a food-safety issue for eggs. Low levels of antibiotics are occasionally, but only rarely, used to prevent disease and ensure the health of laying hens, just as for humans. Very few antibiotics are permitted and there is an economic incentive not to use them due to the additional cost. Rather than routinely, antibiotics are used only if the birds become ill – a rare occurrence because hens have to be healthy to produce eggs. Because so few antibiotics are used and are used to such a small degree, they aren’t likely to contribute to the problem of antibiotic resistance.

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Is genetic engineering used to produce eggs?


Only traditional selective breeding is used in the egg-laying industry. Based on their positive characteristics, specific cocks and hens are chosen as parents for breeding egg layers, a practice which doesn’t involve genetic engineering. If a hen were to be fed genetically engineered feed, any genetic engineering products would be destroyed by the hen’s digestive processes. Research has confirmed that no genetically engineered materials would be passed into the hen’s eggs.

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Are there any people who are at increased risk from foodborne illness?

Yes. Certain people are more likely to become ill or may be affected more severely than normal, healthy individuals and are at increased risk of developing complications from foodborne illness. Infants and children under age 10 contract salmonellosis more often than other age groups. Serve the very young, pregnant women, the elderly, the ill or the immuno-compromised only dishes made from fully-cooked shell eggs or pasteurized shell eggs or pasteurized egg products.

Commercially-prepared mayonnaise, eggnog, frozen entrees, ice cream, egg substitutes, meringue powder, powdered sauce bases, and liquid, frozen and dried egg-white, egg-yolk or whole-egg products are all pasteurized and are suitable for special-risk audiences. When you prepare and store pasteurized egg products, carefully follow package directions to avoid bacterial infection through cross-contamination and spoilage.

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Tell me more about egg products and how I should use and store them.

Egg products are convenience forms of eggs made by breaking and processing shell eggs. Many egg products once sold only for foodservice use are becoming more readily available at consumer retail markets. Most supermarkets now carry egg substitutes, dried and/or refrigerated liquid egg whites and frozen egg entrees, among other egg products.

Federal regulations require that all uncooked egg products be pasteurized. Pasteurization, though, destroys only those bacteria which might be present at the time of processing. All pasteurized foods, including egg products, can become contaminated if you don’t handle them properly after they’re pasteurized. Important handling tips are:

  • Avoid buying any frozen egg products which show signs of thawing. Return frozen egg products to the freezer as soon as possible after you buy them. Thaw them in the refrigerator overnight or under cold running water in tightly sealed containers, not at room temperature. Use thawed egg products promptly. Cover and refrigerate any unused portions and use them within three days.
  • Refrigerate liquid egg products as soon as possible after you buy them. Once you open a liquid product, use it immediately. Pasteurized liquid egg whites can be refrigerated for about 3 to 4 months unopened or about 1 week after opening, or can be frozen indefinitely. Check the label on other products because shelf life can vary.
  • As long as you keep them dry, you can store dried egg whites indefinitely at room temperature, although it’s better to store them in a cool place away from light and strong odors. Store other dried egg products below 70° F in a dark, cool place, preferably in your refrigerator. Reconstitute only the amount of dried egg product you’ll use immediately. After you open it, tightly seal the container and refrigerate any unused portions.
  • Follow the label instructions to refrigerate or freeze specialty egg products.
  • Use a clean utensil to dip egg products from their original containers. Pour an egg product only if the container is designed for pouring and the outside is clean.
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