How to read an egg carton in Thailand

A Thai egg carton can tell you five things: the size number, the grade, how many eggs or how much weight is inside, a date, and how to store the eggs. Thailand has a national egg standard, TAS 6702-2010, which sets these terms. It is a voluntary standard, so a carton may show only some of them.

Size is a number from 0 to 5

In the Thai standard, size is decided by the weight of one egg, not by how big it looks. The number runs from the heaviest egg to the lightest.

No. 0, Jumbo: over 70 g
No. 1, Extra large: over 65 to 70 g
No. 2, Large: over 60 to 65 g
No. 3, Medium: over 55 to 60 g
No. 4, Small: over 50 to 55 g
No. 5, Peewee: over 45 to 50 g

A carton may hold a few eggs of the next size down. The standard allows up to 3.4 percent of the eggs in a pack to be of the immediate smaller size. So a pack marked No. 3 is not guaranteed to be perfectly uniform.

Grade is about the egg, not the size

The standard has three grades, AA, A and B. Grade is judged on the shell, on the air space inside the egg when it is held to a light, and on how the egg looks when broken out.

In Grade AA the shell is clean and smooth, the air space is not more than 0.3 cm deep, and the yolk stands round and bulging in firm white. Grade A allows an air space up to 0.5 cm. Grade B allows up to 0.8 cm, a flatter yolk, a more watery white and lightly stained shells.

A pack is allowed to contain some eggs of the next grade down. For Grade AA and Grade A packs, at least 85 percent of the eggs must meet the named grade, and the rest can be one grade lower.

Quantity, dates and storage

The standard asks for the following on a pack sold directly to consumers, in Thai for the home market:

the words "hen eggs", with grade and size
the number of eggs, or the net weight in grams or kilograms
the name and address of the producer, repacker or distributor
the date of packing and/or a best-before date
a lot number
storage and transport instructions, and a "fragile" warning

The date is the most useful line when you are standing in front of a shelf. Thailand's Department of Livestock Development has advised that the packing and expiry dates on the label are the easy way to tell how fresh a carton is. A later packing date means a younger egg.

For storage, the standard says eggs kept longer than one week should be in a refrigerator or a controlled room at 10 to 13 degrees Celsius.

What a mark on the carton means

A mark is a claim made by someone, and its meaning depends on who defines it.

The Department of Livestock Development describes its Livestock OK mark as showing a product of standard quality, without residues, with a clear source that can be traced back. For the national standard, the use of a certification mark must follow the Agricultural Standards Act.

The word "organic" is held to a higher bar. Under the Thai organic standard, a product labelled organic must come from an organic production system that is inspected and certified, and the label must show the name or code of the certification body.

Cartons from other countries follow other rules. In the European Union, for example, a pack of Class A eggs must show a packing centre code, a quality class, a weight grade shown as a letter (S, M, L or XL), the date of minimum durability and the farming method.

In short

Thai egg size is a number from 0 to 5, and each number is a weight range per egg.
Grade AA, A and B describe shell, air space and how the egg looks when broken out.
A packing or best-before date is the quickest guide to age.
A mark means what its owner says it means, so look for who defines it.
TAS 6702 is voluntary, so some cartons show less than the standard lists.