Topic 1.1 Naturally occurring TFA

Small amounts of TFA occur naturally in some meat and dairy products, including beef, lamb, butterfat, milk (American Heart Association, 2022). The trans isomers of FA naturally present in foods are formed after partial hydrogenation or isomerization of cis-unsaturated fatty acids when bacterial enzymes oxidize feed substrates in the stomachs of ruminants (cows, bulls, sheep). As a result, milk fat, butter, cheese and beef may contain 2-9 % trans fatty acid isomers (ResearchGate, 2010)

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The amount of these fats that will be present in their meat and in the final dairy products depends on the production technology, temperature, time, the addition of other ingredients and the storage of the finished products, as chemical reactions take place at all stages. On average milk fat is composed of 65-70% saturated fatty acids and 30-35% unsaturated fatty acids (European Dairy Association, n.d.). Natural TFAs represent only 4-6% of total milk fat, meaning less than 0.1 g of TFA in 100 mL of full fat milk, which is a residual amount.