The flesh of damaged tuna showed similar total viable count
but equal histamine-forming bacteria levels when compared
with undamaged tuna. Aside from these findings, there was
no significant difference (P < 0.05) in the concentration of
histamine between the damaged (36-53 ppm) and undamaged
tuna muscle (34-59 ppm) (Table 1). These results indicated
that physically damaged muscle was not more susceptible to
microbiological contamination during frozen transportation,
thus indicating that at low temperature there is a minimal
formation of histamine. Three of the tuna fish samples showed
levels of histamine higher than the upper limit established for
the FDA (50 mg-kg) (FOOD…, 1996).