New from Chicken of the Sea is "no-drain" tuna in a 4-ounce can — which the label advises has "No mess!" and "More meat and less liquid than a 5 oz. can." There are three flavors of solid light tuna — lemon pepper, Thai chili and unflavored — and unflavored solid white albacore. All are packed in "just a little water," in cans that Mr. Tidbit measured as, oddly, a little larger than the standard 5-ounce cans.
There is, indeed, very little liquid, but Mr. Tidbit somehow finds that less fascinating than this: Glued over the can's pulltab (on the bottom of the can) is a second label, with a large "Below standard in fill" flag, and an explanation: The FDA requires this warning until they decide how to measure no-drain tuna. That label also advises, cheerfully, "Once you try 'No Drain,' you'll see … It's a No Drainer."
Mr. Tidbit remembers the 7-ounce can of tuna, which became the 6 ¼-ounce can, which became the 6-ounce can, which then became the 5-ounce can, and none of those reductions produced a similar notice from the FDA. Hoping for enlightenment, he stared for a while at Chicken of the Sea's temporary (but lengthy) FDA marketing permit for "no-drain tuna." Then he stared at 21 CFR 161.190, the very lengthy standard for canned tuna.
He thinks he learned that the FDA is allowing this product to deviate from the canned-tuna standard in three ways: There's less liquid than the standard (no; he has no idea why there should be a minimum amount of liquid in a can of tuna), there are flavor ingredients (lime oil, etc.) not now listed in the standard, and the products deviate from the standard's "fill" requirements, which (trust Mr. Tidbit) are essentially unintelligible, but this probably has to do with that oddly larger can.
In short, the FDA's concern is not that the 7-ounce can of tuna is headed from 5 ounces to 4.
At one store, Chicken of the Sea's 5-ounce can of solid light tuna in water was $1.96, and the no-drain 4-ounce can was $2.19.