The January issue of Consumer Reports claimed that the Nordic Naturals fish oil they tested showed signs of rancidity. Nordic Naturals contacted them immediately and to their credit, Consumer Reports has corrected their report (now on their web version but it won't be in print until the February issue). They agree that the test they used for freshness is not a correct one to use in a product with lemon oil.

Nordic Naturals has issued a letter to consumers (pdf) and is going to lead the way to find an appropriate test for such testing in future (pdf).