Growth of psychrotrophic bacteria in raw and UHT-treated goats'milk

Abstract

The growth of six strains of Pseudomonas fluorescens, two of Ps. fragi, and one of Serratia liquefaciens was followed in raw and UHT-treated goats'' milk, held at 4.degree. C. Generation times for Ps. fluorescens in UHT milk ranged from 5.19 to 5.81 h, increasing markedly in raw milk (8.34-21.49 h). Growth of Ps. fragi did not differ significantly between raw (4.56, 4.65 h) and UHT (5.04, 7.24 h) milk. Generation times for S. liquefaciens were 6.63 and 14.07 h, for UHT and raw milk respectively.