Aerobic bacteria and solids in a three-tank, two-pass, counterflow scalder

Scald water and whole carcass rinse samples were collected on 9 different d in a commercial broiler processing plant operating adjacent lines that pro cessed birds from the same flock simultaneously. A conventional, single-tan k, two-pass scalder was installed on one line and the other Line had a thre e-tank, two-pass, counterflow scalder in which water mixed across the two L ines of carcasses within each tank. Water samples from the turn around poin t in each tank were analyzed for aerobic bacteria and suspended solids. At the same time that water samples were taken, six carcasses were removed fro m the processing Line immediately after feather removal and rinsed in 100 m t of phosphate-buffered saline; recovered rinse solution was analyzed for a erobic bacteria using a most probable number procedure. Estimated numbers o f aerobic bacteria were significantly reduced in the third tank of the coun terflow scalder compared to the second tank, or compared to the single tank of the conventional scalder. Despite the differences in aerobic bacteria b etween scald tanks, numbers of aerobic bacteria in carcass rinses were not affected by scalder design. Organic and total solids were significantly red uced in the third. tank of the counterflow scalder compared to the first an d second tanks, and in the third tank of the counterflow scalder compared t o the conventional scalder. Solids in the third (final) tank of the counter flow scalder were reduced by about 70% compared to the conventional scalder .