Effectiveness of Cross-Flow Microfiltration for Removal of Microorganisms Associated with Unpasteurized Liquid Egg White from Process Plant

• Published in: Journal of food science Vol. 74; no. 6; pp. M319 - M327
• Main Authors: Mukhopadhyay, S., Tomasula, P.M., Van Hekken, D., Luchansky, J.B., Call, J.E., Porto-Fett, A.
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.08.2009; Wiley; Wiley Subscription Services, Inc
• Subjects: Algorithms; Analysis of Variance; Biological and medical sciences; Ceramics; Colony Count, Microbial; cross-flow MF; Dietary Proteins - analysis; Effectiveness; Egg and egg product industries; Egg White - microbiology; Eggs; Electrophoresis, Polyacrylamide Gel; Filtration - methods; Food Contamination - prevention & control; Food Handling - methods; Food industries; Food Microbiology; Food preservation; Food science; Food-Processing Industry - methods; functional property; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; liquid egg white; Membranes, Artificial; microbial removal process technology; Microorganisms; Pilot Projects; Refrigeration; Sterilization - methods; Studies; Surface Properties; Temperature; Time Factors; Viscosity; Microfiltration; Technology; cross-flow MF; Egg product; microbial removal process technology; Liquid egg; Egg white; Microorganism; Properties; liquid egg white; functional property
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1750-3841.2009.01228.x

Thermal preservation is used by the egg industry to ensure the microbiological safety of liquid egg white (LEW); however, it does not eliminate all microorganisms and impairs some of the delicate functional properties of LEW. In this study, a pilot‐scale cross‐flow microfiltration (MF) process was designed to remove the natural microflora present in commercial LEW, obtained from a local egg‐breaking plant, while maintaining the nutritional and functional properties of the LEW. LEW, containing approximately 106 ± 1.7 colony forming units (CFU) per milliliter of total aerobic bacteria, was microfiltered using a ceramic membrane with a nominal pore size of 1.4 μm, at a cross‐flow velocity of 6 m/s. To facilitate MF, LEW was screened, homogenized, and then diluted (1 : 2, w/w) with distilled water containing 0.5% sodium chloride. Homogenized LEW was found to have a threefold lower viscosity than unhomogenized LEW. Influence of MF temperature (25 and 40 °C) and pH (6 and 9) on permeate flux, transmission of egg white nutrients across the membrane, and microbial removal efficiency were evaluated. The pH had a significantly greater influence on permeate flux than temperature. Permeate flux increased by almost 148% when pH of LEW was adjusted from pH 9 to pH 6 at 40 °C. Influence of temperature on permeate flux, at a constant pH, however, was found to be inconclusive. Microbial removal efficiency was at least 5 log10 CFU/mL. Total protein and SDS‐PAGE analysis indicated that this MF process did not alter the protein composition of the permeate, compared to that of the feed LEW, and that the foaming properties of LEW were retained in the postfiltered samples.