The total mercury concentrations in raw and subsequently
canned samples of US Pacific troll-caught albacore
tuna were well below the FDA action limit of 1 ppm methylmercury
in fish. There was a significant increase
(p < 0.005) in total mercury concentration as a result of
canning, going from 0.17 ppm in raw samples to
0.21 ppm in canned. Although percent protein increased
significantly and percent moisture decreased significantly
after canning, none of the intrinsic factors correlated with
changes in mercury concentration on an individual can
basis. Raw packing resulted in the highest average percent
increase in mercury concentration, followed by oil and then
water packing; however, there were no significant differences
among the three packing methods. In comparison
to published studies on canned albacore tuna, the results
of the present study showed the lowest total mercury concentration,
most likely due to the relatively small size of US
Pacific troll-caught albacore tuna.