|Luo, Yaguang - Sunny|
Submitted to: Conference of Food Engineers Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 3/15/2008
Publication Date: 4/4/2008
Citation: Luo, Y., Wang, H., Feng, H., Zhou, B. Engineering and Innovation for Enhanced Fresh Produce Safety. Conference of Food Engineers Proceedings. Interpretive Summary:
Technical Abstract: Fresh produce in the U.S. is generally safe, yet several produce related food-borne illness outbreaks in recent years have had severe consequences including large numbers of illnesses, several deaths and significant economic losses for the produce industry. The 2006 outbreaks of Escherichia coli O157:H7 infections due to consumption of contaminated spinach reaffirmed the need to improve microbial safety. Currently, commercial produce wash operations achieve no more than a 1- to 2-log CFU/g reduction in microbial populations without compromising produce quality. The removal and inactivation of bacteria from produce surfaces during washing/sanitizing is a complex phenomenon which depends on the characteristics of bacteria, physical and chemical interactions between the bacterial cells, the produce surface structure and the sanitizer, as well as the hydrodynamics of wash conditions. Few studies have elucidated the mechanisms by which sanitizers exert their effects, or examined the process engineering aspects of wash systems. The aim of this research is to improve fresh produce microbial safety by exploring new chemical and physical means to enhance the efficacy of wash systems to reduce microbial populations. Special emphasis is placed on examining the effects of produce surface topography and wash solution hydrodynamics on washing efficiency. The antibacterial effects of electrolyzed water, a new washing solution, and power ultrasound were studied. A new method using confocal laser scanning microscopy (CLSM) was developed to determine the surface roughness of selected produce which was then correlated to microbial reduction during washing. The surface morphological changes of E. coli K12 cells due to a sanitizing treatment were examined by a MFP-3DTM atomic force microscopy (AFM). The combined use of the new sanitizer and ultrasound achieved the highest population reduction (4.5 log) of E.coli O157:H7 on spinach. This study demonstrates that improving fresh produce safety via an innovative engineering approach is a reachable goal.