Sterilization of Scrambled Eggs in Military Polymeric Trays by Radio Frequency Energy

Abstract

: There is a current need for fresh‐cooked‐like yet shelf‐stable egg products for U.S. military combat rations. Novel thermal processes based on radio frequency (RF) energy can shorten the heating time and reduce overheating. This technology was explored to produce shelf‐stable egg products for combat ration development. Clostridium sporogenes (PA 3679) spores were used as a surrogate to validate the RF sterilization process to control Clostridium botulinum. Decimal reduction time (D value) of PA3679 in scrambled eggs was determined using aluminum thermal‐death‐time (TDT) tubes. The thermal inactivation kinetic information was then used in inoculated pack studies to validate a novel thermal process based on 27.12 MHz radio frequency (RF) pilot scale unit. Trays of scrambled eggs inoculated with PA 3679 were subjected to 3 processing levels: target process (F0 about 5.3 min), under‐target process (F0 about 3.0 min), and over‐target process (F0 about 9.1 min). The results of the microbial challenge study showed that microbial destruction from the RF process agreed with sterilization values calculated from time‐temperature data measured at the cold spot in the treated trays. A comparison of RF‐ and retort‐treated scrambled eggs showed significant differences in the degree of lightness (L*) and redness (a*). RF‐processed egg was less brown compared with conventional retorted eggs. Retort treatment of fully cooked scrambled eggs had higher hardness, springiness, and smaller cohesiveness than RF ‐treated samples. This study suggests that RF thermal processes can produce safe, shelf‐stable sterilized scrambled eggs for both military and civilian uses.

Radio frequency treatment of foods: Review of recent advances

“…The use of chemical marker M-1 as method to map heating patterns was discussed by Wang et al (2004). Previously a number of authors (Luechapattanporn et al, 2004(Luechapattanporn et al, , 2005 successfully validated the use of RF equipment for the sterilisation of samples (mashed potatoes and scrambled eggs) inoculated with Clostridium sporogenes (PA 3679), and achieved sufficient microbial inactivation while producing products which had a higher quality than conventionally retorted products.…”

Radiofrequency pasteurization of inoculated ground beef homogenate

“…Several studies (Guo et al, 2006;Luechapattanaporn et al, 2004Luechapattanaporn et al, , 2005Nagaraj et al, 2015;Zhao, Flugstad, Kolbe, Park and Wells, 2000) have evaluated the effectiveness of RF heating on pasteurizing sausage (Houben, Schoenmakers, Van Putten, Van Roon and Krol, 1991); cured hams (Bengtsson, Green and Valle, 1970;Orsat, Bai, & Raghavan, 1999); and skinless meatloaf (Zhao et al, 2000); sterilizing inoculated mashed potatoes and scrambled eggs with Clostridium sporogenes (PA 3679) (Luechapattanaporn et al, 2004(Luechapattanaporn et al, , 2005 and achieved sufficient microbial inactivation while producing foods with a higher quality than conventionally treated products.…”

Assessment of radio frequency heating on composition, microstructure, flowability and rehydration characteristics of milk powder

“…RFH has been used for defrosting, thawing, drying and post-baking in food industry (Marra et al, 2009), and is developed for inactivating bacteria recently. It was reported that RFH could inactivate E. coli and Listeria innocua in milk (Awuah et al, 2005), Bacillus cereus and C. perfringens in pork luncheon meat (Byrne et al, 2006), and Clostridium sporogenes in scrambled eggs (Luechapattanaporn et al, 2005). Michael et al (2014) displayed that RFH at 90 °C for 5 min could thermally destruct Cronobacter sakazakii and Salmonella spp, the pathogens of most concern, in nonfat dry milk.…”