Ham is pork from a leg cut that has been preserved by wet or dry curing, with or without smoking.

[2] Cato the Elder wrote about the "salting of hams" in his De agri cultura tome around 160 BC.

[5] It was certainly well established by the Roman period, as evidenced by an import trade from Gaul mentioned by Marcus Terentius Varro in his writings.

[8] This process involves cleaning the raw meat, covering it in salt while it is gradually pressed to squeeze out fluid.

Nitrites are used because they prevent bacterial growth and, in a reaction with the meat's myoglobin, give the product a desirable dark red color.

Under certain conditions, especially during cooking, nitrites in meat can react with degradation products of amino acids, forming nitrosamines, which are known carcinogens.

[14] The salt content in dry-cured ham varies throughout a piece of meat, with gradients determinable through sampling and testing or non-invasively through CT scanning.

This can be quicker, increase the weight of the finished product by more than immersion, and ensure a more even distribution of salt through the meat.

For instance, in the United States, the Code of Federal Regulations (CFR) says that "the word 'ham', without any prefix indicating the species of animal from which derived, shall be used in labeling only in connection with the hind legs of swine".

A number of hams worldwide have some level of protection of their unique characteristics, usually relating to their method of preservation or location of production or processing.

Dependent on jurisdiction, rules may prevent any other product being sold with the particular appellation, such as through the European protected geographical indication.

In the United Kingdom, a pork leg cut, either whole or sliced, that has been cured but requires additional cooking is known as gammon.

Cooked ham joints are a popular dish around Christmas time, particularly in the Anglosphere and Northern Europe.