STUDY ON THE ETIOLOGICAL FACTORS OF BILHARZIAL BLADDER-CANCER IN EGYPT .2. NITROSAMINES AND THEIR PRECURSORS IN EGYPTIAN DAIRY-PRODUCTS

Milk, yoghourt and four types of cheese consumed by Egyptians have been analysed for the presence of nitrosamines, and that formed after deliberate chemical nitrosation. Two, three, seven out of ten samples of milk, cottage cheese, white cheese and six out of 9 samples of salted cheese respectively were contaminated with nitrosamines at g × 10-9 level. Deliberate chemical nitrosation produced increasing amounts of both volatile and nonvolatile nitrosamines especially in blue cheese and salted cheese (cottage cheese stored in high concentrations of sodium chloride). The daily consumption of salted cheese and drinking water with high nitrate content, beside a heavily infected urinary bladder due to bilharzial infestation, may contribute to the observed high incidence of bladder cancer among Egyptian farmers. © 1979.