WAEC - Biology (2000 - No. 14)
The following are useful effect of micro-organisms except
production of vaccines
curing of tobacco
tanning of leather
decay of meat
Explanation
Decay in meat is not a useful effect of microorganisms. Microorganisms can cause meat to spoil, which can lead to food waste and food borne infections. Spoilage can cause meat to change color, produce off-flavors, and develop mucus and exudates.