Page 21 - Summer 2019 Journal

ROTTEN VERSUS RANCID
Many concerns about fermented cod liver
oil stem from confusion about the terms “rot- ten” and “rancid.” Rotten, putrified or fermented foods—including meat, fish and fat—are foods that have been predigested by bacteria. In an important 2017 paper published in PaleoAnthro- pology,1 anthropologist John D. Speth explains that “Because of the peculiar properties of many bacteria, including various lactic acid bacteria (LAB), which rapidly colonize decomposing meat and fish, these foods can be preserved free of pathogens for weeks or even months and remain safe to eat.”
Rancid is a term that applies to fats; ran- cidity in fats and oils occurs when they have been exposed to light, heat and oxygen. Under these conditions, fats and oils, especially the highly unsaturated omega-3 fatty acids that characterize marine oils, lose hydrogen atoms and become free radicals, and then break down further into small, highly reactive molecules called aldehydes. Aldehydes present in rancid or oxidized oils may contribute to cancer, arte- riosclerosis, premature aging and many other adverse conditions.
Speth explains that the term “rancid” refers specifically to the degradation of lipids in meat or fish, an “autoxidation” process “quite distinct from what happens to lipids that are fermented or putrified. . .[E]thnohistoric and ethnographic literature frequently conflates these two pro- cesses and as a result can be quite confusing, if not downright misleading.”
Speth continues: “The preservative effects of LAB fermentation. . .are invaluable in pre- venting fats from becoming rancid. For arctic and subarctic people subsisting on diets that were composed almost entirely of animal foods, the large quantities of fatty meat and fish that such a diet demands can be very difficult to dry quickly enough and thoroughly enough to pre- vent the lipids, most especially the long-chain polyunsaturated fatty acids. . .from turning ran- cid and spoiling. . . .Such spoilage can actually pose a health risk by giving rise to a number of undesirable and potentially toxic substances in the meat or fish. The most important of these are a class of compounds known as hydroperoxides, unstable oxidation products that can undergo
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further breakdown, forming a variety of car- bonyl group compounds such as aldehydes and ketones. . . .Fermentation provides an effective means of inhibiting the ‘autoxidation’ of the lipids that leads to rancidity.”2
Thus, among populations that consume high amounts of omega-3 in foods like fish and organ meats, it is the practice of fermentation that protects these fats against rancidity. As explained by Speth: “[A]erobic bacteria in the early stages of putrefaction deplete the supply of oxygen in the tissues, creating an anaerobic environment that retards the production of po- tentially toxic byproducts of lipid auto intoxida- tion (rancidity).” In other words, the practice of making foods “rotten” protects the fatty acids they contain from becoming “rancid.”
The acceptance or rejection of putrified meat is a culturally learned reaction. Whereas many Westerners react with revulsion to the sight and smell of putrified meat and fish, the latter are common among traditional cultures— from the Arctic regions to Africa to the South Pacific. These fermented foods include meat, liver and other organ meats, fish and shellfish, and even hooves and bones. Fermentation techniques include burying in the ground, pre- serving in bogs, placing in animal stomachs or preserving in sewn-up animal skins.
One putrified food that Westerners do enjoy is rotten milk—predigested, fermented and stored unrefrigerated for many months until it becomes covered with mold. It is called cheese—a delicious, highly acceptable food in the West—but which many Asians regard with disgust. In fact, the stinkier the cheese, the more we prize it—just as the Inuit prize stinky fermented fish. Listen to Inuit elder Mary Tyone talk about a native delicacy: “When we fix salmon head we put it in bucket in ground and we take it out and eat it. . . .Stinkfish, oooh, I love that stinkfish. Smell funny, but it sure taste good.”3
Another delightful European fermented food is salami. As Speth explains: “When a body starts to decompose, a forensic scientist would likely refer to what was happening as the onset of ‘putrefaction’. . .[A] food scientist dealing with pork sausages at exactly the same stage of decomposition would refer to the process as ‘fermentation’” [emphasis added].4
Wise Traditions
The practice of making foods
“rotten”
protects the fatty acids they contain from
becoming “rancid.”
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