The influence of oral acid or base load on the processing quality of hams from halothane positive (HP) pigs was examined. HP pigs received either ammonium chloride (8g/L), sodium bicarbonate (12.6g/L) or no additive (HP control) pigs were also slaughtered. Meat from HP animals showed pale, soft exudative properties and was of inferior processing quality to hams of normal quality from HN pigs. Ammonium chloride induced a metabolic acidosis, which further impaired ham quality. Hams from ammonium chloride treated HP hogs had greater thaw purge, less uniform slice appearance and were less juicy than comparable hams from control or bicarbonate treated HP hogs.