The effects of gamma-irradiation doses (0, 0.5, and 1 .O Mrad) on C. botulinurn toxin production in turkey frankfurters formulated with three different chloride salts (NaCl, KCl, and MgClz) at isoionic strength (equal to 2.5% NaCl) and three types of phosphates added to 2.6% NaCl frankfurters were studied. The use of 2.5% NaCl together with 0.5 or 1 .O Mrad was substantially more effective at inhibitinlg botulinal toxin production when frankfurters were incubated at 27°C than the combination of irradiation with KC1 or MgC12 (40, 9, and 4 days, respectively, when treated with 1 Mrad). Phosphate addition revealed that 0.4% sodium acid pyrophosphate addition was the most inhibitory for botulinal toxin production followed by hexametaphosphate and tripolyphosphate addition.