Contaminants in local alcoholic beverages: zinc and manganese contamination

The extent of leaching of zinc (Zn) and manganese (Mn) from the vessels used during the preparation of two local alcoholic drinks, Pito and Burukutu has been assessed. Leaching of these metals during the four phases of fermentation was monitored by determining the levels of the metals in each phase using atomic absorption spectrophotometric technique; in each complete fermentation protocol, metallic or clay container was used. Contamination appeared to be due to the fermentation process, container used or a combination of the two. Comparatively, there was increase in the levels of these metals from the initial to the final phase of fermentation for both types of vessels; in each case, appropriate controls were used. Compared to control values, the average increase in the level of zinc in Burukutu and Pito for metallic and clay containers is 343%; 325% and 295%; 252% respectively; whereas for manganese the increases are 815%; 1438% and 1292%; 1150% in that order. The differences in the levels of these metals among the phases in each of the drinks were significant (