COMBINED EFFECT OF NISIN AND HIGH HYDROSTATIC-PRESSURE ON DESTRUCTIONOF LISTERIA-INNOCUA AND ESCHERICHIA-COLI IN LIQUID WHOLE EGG

High hydrostatic pressure inactivation of Escherichia coli and Listeri a innocua inoculated in liquid whole egg was improved significantly (P < 0.05) with nisin addition at concentrations of 1.25 and 5 mg/l. A r eduction of almost 5 log(10) units in E. coli counts and more than 6 l og(10) units for L. innocua was obtained at 450 MPa and 5 mg/l of nisi n. For this treatment, the two microorganisms were not detectable afte r 1 month of storage at 4 degrees C. The amount of nisin added did not affect E. coli inactivation at 300 MPa. Fcr L. innocua, 5 mg/l of nis in was more effective than 1.25 mg/l, Nisin showed no effect when samp les were stored at 20 degrees C after pressurization, except for sampl es with L. innocua containing 5 mg/l of nisin and treated with 450 MPa . (C) 1998 Elsevier Science B.V. All rights reserved.