Buying & Storing Eggs


What to look for on an egg label

When shopping for eggs you should find lots of information on the packaging including the farmer and farming method, egg size, best-before date and nutrition information.

A number of egg farming methods are used in New Zealand providing a range for consumer choice, and all commercial egg farmers in New Zealand have agreed as a whole to voluntarily label their products.

Egg size varies from about 40-80 grams per egg. These are sold by grade (4, 5, 6, 7, 8), based on a minimum size for the grade:

  • Jumbo (8): 68g
  • Large (7): 62g
  • Standard (6): 53g
  • Medium (5): 44g
  • Pullet (4): 35g
  • Mixed grade – a selection of different sized eggs

Choosing an egg size is usually based on preference and price, as larger eggs often cost slightly more, although some baking recipes may call for eggs of a particular size.

Eggs should be labeled with a best-before date. Eggs refrigerated after purchase at 4C or below can be safely used up to the best-before date (around 35 days from being laid) and there will be little or no change in the egg quality. After this date they are recommended for use in baking.

How to Choose Quality Eggs

  • Always check inside the carton before purchasing
  • Do not purchase any eggs that are cracked or soiled (feathers or droppings on the shell)
  • A rough shell with pinhead-sized lumps could be from an older hen or one that has too much calcium in its diet. These lumps could rub off and leave holes in the egg. If the shell is completely intact, the edible egg is not affected by the rough shell.
  • If an egg is irregular with a flat side it means it was probably disturbed during laying. This does not affect the egg’s eating quality.
  • Inside the egg, blood spots or meat spots can occur. These can easily be removed by the cook and the egg cooked as usual once cracked

More information about the factors affecting egg quality in commercial laying hens (PDF).


Keep eggs or egg products (mayonnaise etc) refrigerated at 4C or below when you’re not cooking or eating them. These foods should not be left at room temperature for more than 2 hours, including the time you use to prepare and serve them.
Eggs are porous, which means smells and liquid can be absorbed by the tiny pores on the eggs shell. Storing eggs in their cartons in the fridge helps prevent this. Place egg cartons on a middle or lower shelf rather than in the door of the fridge so the temperature is more consistent.

How can I store leftover egg whites and yolks?

You can refrigerate raw whites for up to 4 days and unbroken raw yolks covered with water for up to 2 days in a tightly sealed container. If you can’t use the yolks quickly enough, hard cook them just as you would cook whole eggs in the shell, drain them well and refrigerate them in a tightly sealed container for up to 4 or 5 days. 
For longer storage, freeze raw whites, sugared or salted yolks and cooked yolks for up to 1 year.
To freeze egg whites, break and separate the eggs, one at a time, making sure that no yolk gets in the whites. Pour the whites into freezer containers, seal the containers tightly, label with the number of egg whites and the date and freeze. For faster thawing and easier measuring, first freeze each white in an ice cube tray and then transfer to a freezer bag or container. Substitute 2 tablespoons thawed egg white for 1 large fresh white.
Raw egg yolks require special treatment because the yolk’s gelation property causes it to thicken or gel when frozen making it almost impossible to use. Beat in either ⅛ teaspoon salt or 1 ½ teaspoons sugar for each ¼ cup egg yolks (4 large yolks). Label the container with the number of yolks, the date and whether you’ve added salt (for main dishes) or sweetener (for baking or desserts) and freeze. Substitute 1 tablespoon thawed egg yolk for 1 large fresh yolk. 

Food safety tips for storing eggs

Like all perishable foods, eggs need to be handled carefully. Follow these suggestions to ensure that you handle and prepare eggs properly: 

  • Always buy shell eggs that are clean and keep them refrigerated at home 
  • When storing eggs in the refrigerator, keep eggs in the carton and at a reasonable distance from other strongly flavoured / smelling foods items 
  • For all perishable foods allow no more than two hours at room temperature for preparation and serving 
  • Eggs should be cooked until the white is completely firm and the yolk begins to thicken 
  • For best quality, use fresh eggs within the ‘Best Before’ date as stated on the carton. Avoid cross-contamination by washing hands, cookware, and counter-tops with hot, soapy water after preparing raw animal products, including eggs.