ARS | Publication request: Removal of Bacillus anthracis sterne spore from commercial unpasteurized liquid egg white

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 31, 2010
Publication Date: July 17, 2010
Citation: Mukhopadhyay, S., Tomasula, P.M., Kwoczak, R., Porto Fett, A.C., Call, J.E., Luchansky, J.B. 2010. Removal of Bacillus anthracis sterne spore from commercial unpasteurized liquid egg white. Meeting Abstract. 273-01. p.77.

Technical Abstract: Thermal pasteurization used by the egg industry for controlling vegetative cells of pathogens is ineffective for destroying endospores. There is a strong need in the agri-industries to develop effective intervention strategies to eliminate the possible bioterrorism threat from spore forming bacteria such as Bacillus anthracis (BA) in liquid eggs and other value added commodities. This study was conducted to examine the feasibility of membrane processing technology for separation of a surrogate strain of BA (Sterne) spores from liquid egg white (LEW). Unpasteurized LEW from a local egg breaking plant was inoculated with the avirulent Sterne strain of BA to a level of approximately 106 spores/mL and microfiltered (MF) using a ceramic membrane of average pore size 1.4 micron. Prior to MF, unpasteurized LEW was pretreated, first by homogenizing and then diluting the homogenized LEW with water (1:2 w/w) containing 0.085 M sodium chloride to facilitate protein permeation. The processing parameters such as pH and temperature were optimized to ensure maximum spore separation with minimal loss of functional quality. Spore removal efficiency and kinetics were evaluated to determined process robustness. The pH of the LEW is the predominant factor influencing the flow of permeate. The permeate flux increased by 50 l/h.m2 per unit pH decrease, which is almost 30 times greater compared to the rate of increase in flux due to unit deg C increase in temperature. Spore removal efficiency was at least 6.14 log 10 spores /ml. Storage stability of MF processed LEW showed no outgrowth of spores for up to 21 days at 4 deg C. Total protein content of LEW was stable before (2.97%) and after (2.88%) MF. The data reported in this investigation shows that cross flow MF of LEW, prior to pasteurization, can remove at least 99.9999% of BA spores without affecting the functional properties of LEW.