Final Examination for the Degree of MSc Food Science - Mubashira Zaidi

Examining Committee  
Dr. Yoshi Mine, Chair  
Dr. Jeffrey Faber, Advisor  
Dr. Sampathkumar Balamurugan, Co-Advisor   
Dr. Keith Warriner, Department Member  
  
TITLE: UV RESPONSE OF CRONOBACTER SAKAZAKII IN BUFFER AND PARTLY SKIMMED MILK USING A LOW-PRESSURE COLLIMATED BEAM AND DEAN FLOW-THROUGH REACTOR
  
ABSTRACT:  
In this era of novel and new inactivation techniques in foods, ultraviolet radiation is one of the promising methods. Using UV light for the inactivation of pathogens in food and  beverages has shown good results qualitatively, economically, and sustainably. In this  research,  UV light was used to obtain the D10 values of 13 strains of Cronobacter spp. in  buffer. Among the strains, 10 were C. sakazakii, two were C. muytiejensii and one C. dublinensis. The D10 values ranged from 2.08 to 3.14 mJ/cm² (p ≤ 0.05). In the second  part of this study, a five-strain cocktail of C.  
sakazakii suspended in 2% partly skimmed  milk was treated with UV light at different flow rates obtained by using a Dean flow-through  reactor. A total  reduction of 2.47 ± 0.10 logs was achieved at a flow rate of  10 mL/min. This study provides useful information that can help to establish the efficacy of UV treatment for inactivating Cronobacter spp. in commercial milk.