Food & Nutrition

Arab Journal of Food & Nutrition
100. Comparison of the Thermal Inactivation of Enterobacter sakazakii in
Different Types of Rehydrated Milk and Infant Milk Formula (2008)
Mohammed Salman Alhaddaq\ Jordan University of Science & Technology
Supervisor: Dr. Tareq Osaili
Enterobacter sakazakii is an opportunistic food-borne pathogen that has been
involved in severe forms of human infection. This study determined the thermal
resistance of E. sakazakii in milk with different fat levels and in special use feeding
formula. E. sakazakii cells were mixed with the reconstituted milk or feeding formula
at 52, 54, 56, and 58 °C for various time periods or mixed with powdered milk or
feeding formula prior to reconstitution with water at various temperatures. The D- and
z-values were determined by using linear regression analysis. D-values of E. sakazakii
at 52 to 58 °C in whole milk ranged from 22.10 to 0.68 min and were significantly
higher than those in low fat or skim milk. D-values of E. sakazakii at 52 to 58 °C in
lactose free infant milk formula were significantly higher than those in soy protein formula.
The z-values of E. sakazakii in reconstituted milk and feeding formula ranged
from 4.01 to 4.39 °C and from 4.18 to 4.27 °C, respectively. Thermal resistance of E.
sakazakii in powdered milk and powder feeding formula were consistent with their
thermal resistance in the reconstituted products. Water at ≥ 70 °C caused > 4 log
reduction of E. sakazakii in powdered milk and powder feeding formula. The results of
this study may be of use to regulatory agencies, milk producers and caregivers to
design heating processes to eliminate E. sakazakii that may be present in these
products.
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Volume 11, No. 25, 2011
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