What's in an Egg? Demystifying the Labels

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An egg carton might be festooned with various labels about how the hens are treated and what the eggs do, or don't, contain. Some provide some valid information for the consumer, but others fall into the "true but misleading" category. Here's a breakdown of the different types of incredible edibles. 

As with many other foods, egg purveyors present a variety of eggs (and we still mean only those produced by chickens) for consumers to choose from. So many, in fact, that one is likely to be confused by the labels — what's the difference between brown eggs and white, or between free-range and cage-free eggs? Or is there one? To demystify the labeling of these sources of complete protein and other nutrients, we searched the website of the Egg Nutrition Center to try to make some sense out of the egg marketplace. We've done this before, but in the year or so since then, even more categories have been added. Some of the labels relate to how the laying hens are treated, while others refer to the nutrient content of the eggs themselves. Here's the lowdown:

How  the laying hens are treated is reflected by several labels:

  • Conventional: Hens are maintained in small cages.
  • Cage-free: Hens are allowed to roam in a building, room, or open space where they can access nest space and perches.
  • Pasture-raised: Hens can roam and forage in a maintained pasture area. This type of environment isn't yet defined by the USDA — the agency hasn't set standards for it.
  • Free-range: Hens have access to the outdoors and aren't housed in enclosures. Like pasture-raised hens they can forage for plants and insects.
  • Enriched colonies: Hens are in enclosures that have perches, nest space, and areas where they can take dust baths and scratch in the dirt.
  • Certified Organic: Hens are cage-free or free-range with access to the outdoors. They are fed organic feed grown without synthetic pesticides, fungicides, herbicides or fertilizers.

In addition to differences in hen housing, there can be differences in how the eggs are treated or what they might contain:

  • Pasteurized eggs: Eggs are heated to destroy any disease-causing bacteria, such as Salmonella.
  • Vegetarian: Eggs are laid by hens fed a vegetarian diet.
  • Omega-3 Enriched: Hens producing these eggs are fed diets that are especially rich in omega-3 fatty acids, which then results in eggs with more than the usual amount of these nutrients.
  • Gluten-free: This is accurate but misleading, since no eggs contain gluten, even if the hens producing them have eaten gluten-containing grains.
  • Hormone-free: Again, accurate but misleading since hormones aren't used in egg production.
  • Antibiotic-free: Yet another accurate but misleading claim, since such drugs aren't used in producing eggs. If hens are sick and treated with antibiotics, their eggs aren't sold for human food.
  • Brown eggs: They are no different from white eggs except in the shell color. They are just produced by different breeds of chickens.
  • Yet other labels that could be misleading include "Zero Trans Fats" or "Zero Carbohydrates" because no eggs contain either.

And you might see a sell by date on the egg carton, and eggs can be eaten safely 2-3 weeks after that date.

So some of the labels you might come across on egg cartons provide some valid information — but some don't. And knowing which is which may save some money on your next shopping trip.