TEMPERATURE PROFILES IN HOLDING TUBES OF MILK AND EGG PASTEURIZERS

Product temperatures in a cross-section of the holding tube of milk and egg pasteurizers are required to be within 1 F, and this condition is assumed to be met when tube diameter is < 7 inches and product velocity is at least 1 ft/sec. Because of the viscous nature of some milk products and most egg products, the 1 F requirement might not be met, and therefore product temperatures were measured at the entrance and exit cross-sections of both milk and egg holding tubes. Product temperatures were measured with 0.010-inch-diameter thermocouples and a 24-point recorder. With the pasteurizer operating with product in forward flow, holding tube temperatures were monitored for about 0.5 hr. Except for condensed skimmilk, milk product temperatures in a cross-section did not vary by more than 0.8 F. Although the temperature variation of condensed skimmilk exceeded the 1 F requirement, it was within 2 F. For plain yolk and for salted yolk (10% salt by weight) the variation within a cross-section was 1.2 and 4.8 F r...