Radiation Preservation of Milk and Milk Products. II. Off-Flavors in Milk and Cream Induced by Ionizing Radiations as Judged by Organoleptic Tests

Abstract

Various types of whole and skimmilk were investigated; the threshold dose at which off-flavor induced by high voltage cathode rays was recognizable ranged from about 7000 to 25,000 rep, depending on the product. Acceptability of irradiated products decreased with increasing dose. Susceptibility of milk to radiation induced off-flavor development was not significantly altered by prepasteurization by the "High Temperature Short Time" method but was significantly affected by homogenization. Increase in moisture and fat contents of the milk and cream influenced the threshold dose level at which off-flavors were recognizable and caused an increase in off-flavor production. As the total solids increased the product became less susceptible to flavor change. In a product such as cream there appears to be a balancing of susceptibility and protection due to an increase in both fat and total solids content. Use of mathematical line-fitting and confidence limits on log probability paper offers a new method of studying significant flavor differences at the threshold level.