▁Department ▁oper ates ▁a ▁research ▁facility ▁at ▁K err ▁Wild life ▁Management ▁Area , ▁where ▁they ▁examine ▁fer al ▁p ig ▁feed ing ▁prefer ences ▁and ▁b ait ▁tact ics ▁to ▁admin ister ▁sod ium ▁nit rite . ▁ ▁Car cin ogen icity ▁Car cin ogen icity ▁is ▁the ▁ability ▁or ▁t endency ▁of ▁a ▁chemical ▁to ▁indu ce ▁tum ors , ▁increase ▁their ▁inc idence ▁or ▁m align ancy , ▁or ▁short en ▁the ▁time ▁of ▁tum or ▁occurrence . ▁ ▁Me at ▁cur ing ▁safety ▁N it ros am ines ▁can ▁potentially ▁form ▁when ▁sod ium ▁nit rite - tre ated ▁meat ▁is ▁cook ed . ▁Such ▁car cin ogen ic ▁nit ros am ines ▁can ▁also ▁be ▁formed ▁from ▁the ▁reaction ▁of ▁nit rite ▁with ▁secondary ▁am ines ▁under ▁acid ic ▁conditions ▁( such ▁as ▁occurs ▁in ▁the ▁human ▁st om ach ) ▁as ▁well ▁as ▁during ▁the ▁cur ing ▁process ▁used ▁to ▁preserve ▁me ats . ▁Diet ary ▁sources ▁of ▁nit ros am ines ▁include ▁US ▁c ured ▁me ats ▁preserved ▁with ▁sod ium ▁nit rite ▁as ▁well ▁as ▁the ▁d ried ▁salt ed ▁fish ▁e aten ▁in ▁Japan . ▁In ▁the ▁ 1 9 2 0 s , ▁a ▁significant ▁change ▁in ▁US ▁meat ▁cur ing ▁practices ▁resulted ▁in ▁a ▁ 6 9 % ▁decrease ▁in ▁average ▁nit rite ▁content . ▁This ▁event ▁preced ed ▁the ▁beginning ▁of ▁a ▁dram atic ▁decl ine ▁in ▁g astr ic ▁cancer ▁mort ality . ▁Ar ound ▁ 1 9 7 0