Four levels of NaNO2 (0 ppm, 50 ppm, 100 ppm, and 156 ppm) were tested for antibotulinal activity in ground pork inoculated with spores of Clostridium botulinum either at the time of formulation or after cooking. Samples formulated with less than 156 ppm sodium nitrite received additional nitrite to adjust the residual nitrite equal to that found after cooking in samples formulated with 156 ppm nitrite. All samples were subjected to abusive storage at 27 C. Inoculating the spores at the time of formulation resulted in a faster rate of swelling. Heating C. botulinum spores for 30 min. at 77 C before addition to cooked meat also resulted in rapid germination. Total botulinal counts were significantly higher (p=0.05) in these samples, compared with similarly treated samples formulated with unheated spores. Samples formulated with 50 ppm initial sodium nitrite and with 78 ppm additional NaNO2 after cooking were the most inhibitory. Initial nitrite concentration was shown to be important for inhibition of C. botulinum growth, probably because of the inhibitory carryover effects of protein-bound nitrite formed during cooing, as well as influencing the concentration of residual nitrite.