Curing meat has developed over many thousands of years from a purely necessary point of making food last longer to using it as a process to alter appearance and flavour. Initially the curing of meat was achieved by drying alone, then this was combined with smoking to more efficiently dry the meat and flavour it.
The process of curing using salt (sodium chloride) draws the water out from microorganisms in a process called osmosis slowing down their growth. Salt also inhibits the oxidation process, extending the time it takes for the meat to ‘go off’.
The addition of nitrites or nitrates further enhances the preservation and results in the characteristic ‘red’ colour we associate with bacon and ham. The addition of nitrites and nitrates to food products is tightly regulated, as excess amounts can be unhealthy, although they are considered essential in controlling bacteria growth and in particular the growth of the bacteria which can cause botulinum poisoning.
In general, for the production of cured meats which will subsequently be cooked, such as bacon, ham, sausages etc. the choice is Sodium Nitrite, this acts very quickly to protect the meat. This cannot in general be purchased on its own and will come premixed with salt. This is because the quantities required are so small that it would be very difficult to mix it with the other curing agents accurately and evenly. The product is supplied under various names, ‘Cure No 1’, ‘Prague powder No. 1’, or ‘Pink Curing Salt’. This is a premixed product which will contain 5.88 Percent Sodium Nitrite and 94.22 Percent salt.
When curing meat products which will not be cooked, like salami, chorizo, pancetta, etc. then Cure No. 2 will be used. This contains Sodium Nitrate. The curing and drying process for these types of meats is longer, typically weeks, rather than days. Over the time of the cure, the nitrate reacts with the natural bacteria in the meat and converts to nitrite. Production of these types of cured meats is in general more complex and demands a slightly more complex setup to achieve, especially for the novice, but is by no means unachievable.