Ooligan grease: a traditional food fat of western Canada and Alaska

First Nations Peoples prepare ooligan grease by ripening several tons of the small fish, Thaleichthys pacificus, and rendering the fish oil. Eighteen samples from different family preparations of five cultural areas were analyzed for a spectrum of nutrients, organochlorines, and heavy metals. Ooligan grease was found to be a rich source of retinol (2444 +/- 1198 RE/100 g) and n-3 fatty acids, but had less vitamin A compared to fat of raw fish. There was a 10-fold increase in n-3 fatty acids in grease compared to raw fish fat, which may be attributed to microbial conversion of other fatty acids to DHA. Whole fish were good sources of Ca, Fe, and Zn; heavy metals were below guideline levels in grease. Chlorinated pesticides and PCB increased from north to south locations in British Columbia, with mean levels being 110 ng/g lipid of total chlorinated pesticides and 30 ng/g lipid of PCB. These levels are below regulation limits established by Health Canada. It is concluded that ooligan grease is a superior food fat and safe for human consumption.