Carbohydrates are determined in food from animals as result of contamination. Therefore they are a risk for the consumer and may impair the quality of the products. There are differences in the pattern of residues between the groups of carbohydrates. Especially the saturated carbohydrates indicate heavy differences. Aromatic carbohydrates have an equalized level. These relationships are examined by tests with n-alkane-yeasts-feeding of pigs.