Factors affecting premature browning during cooking of store-purchased ground beef

Storage conditions, patty location within packages, and purchase time effec ts on premature browning (PMB) of ground beef during cooking to 55 degrees C were determined. Packages were purchased twice daily. Patties were formed soon after purchase or after overnight storage (4 degrees C). Patties from the outer portion of the packages purchased in the morning were bright red and had the highest incidence of PMB (62.5%) when cooked. Patties from inn er portions of packages purchased in the afternoon and refrigerated overnig ht were more (P < 0.05) purple and had the lowest incidence (25%) of PMB. P remature browning incidence averaged 47%. Consumer handling procedures affe cted PMB apparently by changing the state of myoglobin in the packages.