Reduction of Salmonella Enteritidis in Shell Eggs Using Directional Microwave Technology

Abstract

Microwaves have been shown to cause thermal as well as nonthermal destruction of pathogens such as Salmonella Enteritidis, which is commonly found in shell eggs. The objective of this study was to examine the use of new directional microwave technology to reduce Salmonella Enteritidis without causing any detrimental effects on quality in white and brown eggs. Treatments were control and microwaved white and brown eggs. Applying directional microwave technology resulted in a 2-log reduction of Salmonella Enteritidis in both the high (10(5) cfu/g) and low (10(2) cfu/g) inoculum. At d 0, there were no differences in water activities, albumen pH, and combined pH between treatments; however, there were significant changes in yolk pH. Collectively, these results indicate that applying directional microwave technology can reduce Salmonella Enteritidis in shell eggs without causing any detrimental effects to quality.

Alternative egg decontamination techniques to washing

“…Different studies have been proposed about the use of microwave to reduce bacterial load in shell eggs (Jeng et al 1987;Stadelman et al 1996;Ferroni et al 2003;Dev et al 2007;Sivaramakrishnan 2007;Lakins et al 2008).…”

“…As regards directional microwave technology, Lakins et al (2008) andFerroni et al (2003) proposed treating eggs by an innovative technology very different from commercial or household microwaves using microwave equipment with horizontal and rotary movement and several sources of (2003) reported a reduction of up to 80% in Salmonella Enteritidis using a 10 3 cfu/ml yolk inoculum level. The authors reported that the pH, the weight and the sensory characteristics showed no significant differences between eggs treated by directional microwave technology and non-treated eggs.…”

“…The effect of microwaves on pathogens can generally be expressed in two forms: thermal and non-thermal destruction of pathogens (Lakins et al 2008). The first is caused by the heating of food during the microwave process, while the second can be caused by four different phenomena: selective heating, electroporation, cell membrane rupture and magnetic field coupling (Kozempel et al 1998).…”

“…The electrical potential crosses the membrane of the bacteria causing the formation of pores in the membrane while the voltage across a membrane induces cell membrane rupture. Magnetic field coupling causes a disruption in the internal component of the cell, leading to cell lysis (Lakins et al 2008).…”

Inhibitory Effect of Plant Extracts on Salmonella spp.

“…Kuo et al (1997) determined that UV radiation significantly reduced S. typhimurium inoculated on shell eggs. Directional microwave technology resulted in more than 2-log reduction of S. enteritidis in shell eggs without causing any detrimental effects to quality reviewed by Lakins et al (2008). The effectiveness of steam treatments on meat and poultry has been investigated, which the presence of a number of pathogens may be reduced by the application of steam to meat surfaces, mostly gram negative enteric pathogens, such as Escherichia coli O157:H7 and a number of Salmonella serotypes (James et al, 2000;Phebus et al, 1997;Whyte et al, 2003).…”