Abstract

The malondialdehyde (a deleterious by-product of lipid peroxidation) and N-nitrosamines and their precursors (nitrate and nitrite) content of seven (7) and three (3) brands of Nigerian yogurts and ice-creams respectively as well as that of some meat and fish samples were determined using chemical methods. Malondialdehyde and nitrite were estimated spectrophotometrically, nitrate after reduction to nitrite with cadmium column and N-nitrosamines after decomposition to nitrite using U.V irradiation. Malonaldehyde was detected in all the samples of both ice-creams and yogurts and in some meat and fish samples with mean concentration of 1.79 ± 0.13- 9.11 ± 2.67 µg/ml in the food drinks and 0.51±0.01 - 1.68 ± 0.03 µg/g and N.D – 12.95 ± 1.07 µg/g in fish and meat samples respectively. All the brands of ice- creams and yogurts (except Brand B) analyzed contained detectable amounts of nitrite. The mean values in µg/ml ranged 0.06 ± 0.01 – 0.2±0.01µg/ml for ice creams and 0.07 ± 0.01 – 0.04 ± 0.02 µg/ml for yogurts. Measurable concentrations of nitrate (0.64 ± 0.04 – 4.91 ± 0.51 µg/ml) and N-nitrosamines were also found in some of these food drinks. The toxicological implications of these findings are discussed. 

Key words: Malondialdehyde, nitrate, nitrite, n-nitrosamines, ice creams, yogurts, fish, meat.