I will try to differentiate the following term to avoid confusion. Reading from other sources is still recommended as I cannot guarantee its accuracy. One thing is for sure however, all term listed below may cause health problems.
What is Salitre? It is a Tagalog term or maybe a borrowed language from Spaniards. Aka saltpeter.
Salt peter is a collective term referring to three substances, the potassium nitrate, sodium nitrate and sodium nitrite. Not sure which came first but I think it was the potassium nitrate. If the term salitre only refers to potassium nitrate, then the claim “walang salitre / no salpeter added” is true.
All three substances shares the same function in food industry. They are strong oxidizing agent use to prevent growth of bacteria especially the botulinum bacteria. It also give the characteristic red color to meat, dull brown instead if not added.
Degradation occurs when meat is heated. Degradation product called amines combine with nitrite forming nitrosamines – a well known carcinogen. Sodium nitrite, obviously, is not recommended. Potassium nitrate and sodium nitrate are used instead cause nitrate do not bind with amines. Sodium nitrate is preferred cause it is more heat stable. However, both nitrate substances convert to nitrite inside human body and may bind to available amines. Nitrosamines are also formed when the cured meat is cooked over high temperature for prolonged period.
The prague powder , aka curing salt or the pink salt. According wiki, prague powder 1 contains 93.75% table salt and 6.25% sodium nitrite while prague powder 2 contains both sodium nitrate and sodium nitrite.
Refer to “Curing Salt / Prague Powder, Composition and Safety Issues” to know its side effects.