RESIDUAL LEVELS OF FREE AND TOTAL SULFITE IN FRESH AND COOKED BURGERS

Forty samples of fresh and fried burgers were analysed. A habitual use and often abuse of sulphites was detected. In the case of the uncooke d samples, 62.5% contained residual levels of total SO2 above 450 mug/ g. The frying process was found to lead to a mean reduction of 36.8 +/ - 11.1% in the case of free sulphite and of 40.9 +/- 12.6% for total s ulphite. This reduction was independent of the concentration of sulphi te present and did not seem to be related to the type of meat used. Mo st burgers cooked in restaurants were found to contain sulphites, some times at elevated levels. The HPLC analytical method for the determina tion of sulphite contents in burgers, previously applied to fresh saus ages, was compared with the optimized Monier-Williams method. The resu lts obtained with both methods in the determination of total SO2 were found to have the same precision although there were significant diffe rences in the contents of additive (p < 0.05).