PH CHANGES IN SMOKELESS TOBACCOS UNDERGOING NITROSATION DURING PROLONGED STORAGE - EFFECTS OF MOISTURE, TEMPERATURE, AND DURATION

Three smokeless tobacco research products were each adjusted to two mo isture levels before storage for 48 weeks at 24 and 32-degrees-C. The pHs of high water content moist snuff (55.5%) and dry snuff (remoistur ized to 51.4%) increased 0.3-2.1 pH units during the storage. In contr ast, the pHs of decreased water content moist snuff (21.9%) and dry sn uff (12.3%) decreased by 0.2-0.4 unit. Chewing tobacco pHs at high (49 .3%) and low (22.3%) moisture levels and at each moisture-temperature treatment decreased during storage. Nitrosated pyridine alkaloids incr eased only in tobaccos that became more alkaline during storage. Inter actions between the effects of moisture and temperature occurred. Heat ing snuffs at 100-degrees-C for 30 min at zero storage time prevented the increases of pH, nitrosamines, and nitrite observed in non-heat-tr eated controls during storage. The results support the view that incre ases of nitrosamines may be mediated by microbial growth.