Saltpetre, or potassium nitrate, is used as a curing agent in preserving meats. It helps the meat retain a pink colouration and inhibits the growth of harmful bacteria, such as Clostridium botulinum (botulism). However, it can be toxic if used incorrectly. The National Center for Home Food Preservation at the University of Georgia recommends that home food preservers use commercially available substitutes for greater safety.
Prague Powder #1
Prague Powder #1 is a mix of sodium nitrite and salt. It is also known as InstaCure, Modern Cure or curing salt. The recommended amount is 1 tsp for every 2.27kg of meat or 28.4gr. for every 11.3kg of meat. Prague Powder #1 is used for meats that will not be frozen or refrigerated immediately, such as smoked or dehydrated meats.
Prague Powder #2
Prague Powder #2 is a mixture of salt, sodium nitrite and sodium nitrate. It is used for meats that will be dry-cured over a long period of time, like pepperoni or salami. The sodium nitrate breaks down during the curing process, first into sodium nitrite and then into nitric oxide. The recommended amount is the same as for Prague Powder #1--1 tsp for every 2.27kg of meat or 28.4gr. for every 11.3kg of meat.
Morton's Tender Quick
Morton's Tender Quick is a mix of salt, sugar, sodium nitrite and sodium nitrate. It is used in the dry- or pickle-curing of meat, fish and poultry. The recommended amount is 1 1/2 tsp for every 0.454kg of meat. Morton also makes a product called Sugar Cure, which can be substituted for Tender Quick, especially in ham or bacon.