The occurrence of semicarbazide in the meat and shell of Bangladeshi fresh-water shrimp

► Trace levels of semicarbazide (SEM) can be found in meat of Macrobrachium rosenbergii shrimp wild-caught in Bangladesh. ► SEM concentrations are 100 times higher in shrimp shell and suggests natural occurrence. ► Validity of SEM as a marker residue for nitrofurazone is questioned. ► Shrimp meat only rather than shrimp plus shell should be tested for SEM.