THE EFFECTS OF ELECTRON BEAM IRRADIATION AND SANITIZERS IN THE REDUCTION OF PATHOGENS AND ATTACHMENT PREVENTION ON SPINACH
Abstract
The effects of electron beam (e-beam) irradiation and sanitizers in the reduction
of Escherichia coli O157:H7 and Salmonella counts and attachment prevention on
spinach was studied. Survival of these pathogens in spinach was observed at multiple
times and temperatures. Inoculated spinach was examined by confocal microscopy to
determine attachment sites and internalization of these pathogens. To determine the
effectiveness of sanitizers in reducing pathogen numbers, inoculated spinach was treated
with L-lactic acid, peroxyacetic acid, calcium hypochlorite, ozone, and chlorine dioxide.
Inoculated spinach was exposed to e-beam irradiation and tested for counts of both
pathogens immediately after irradiation treatment to determine bacterial reduction, and
at 2 day intervals over 8 days to determine effects of ionizing irradiation on pathogen
survival. Respiration rates were measured on spinach exposed to e-beam. The
effectiveness of e-beam irradiation on the microbiological and sensory characteristics of
spinach was studied. For spinach samples stored at 4�C and 10�C for 8 days, E. coli
O157:H7 survived and grew significantly in samples stored at 21�C for 24 h. Confocal microscopy images provided valuable information on the attachment sites and
internalization of the pathogens on spinach. The greatest reduction by a chemical
sanitizer was 55�C L-lactic acid with a 2.7 log CFU/g reduction for E. coli O157:H7 and
2.3 log CFU/g reduction for Salmonella. Each dose of e-beam irradiation significantly
reduced populations of both pathogens. Respiration rates of spinach increased as
irradiation treatment doses increased. Total aerobic plate counts were reduced by 2.6 and
3.2 log CFU/g at 0.7 and 1.4 kGy, respectively. Lactic acid bacteria were reduced at both
doses but grew slowly over the 35 day period. Yeasts and molds were not reduced in
samples exposed to 0.7 kGy whereas 1.4 kGy had significantly reduced counts. Gas
compositions for samples receiving 0.7 and 1.4 kGy were significantly different than
controls. Irradiation did not affect the objective color or basic taste, aromatic or
mouthfeel attributes of spinach. These results suggest that low dose e-beam irradiation
may be a viable tool for reducing microbial populations or eliminating E. coli O157:H7
and Salmonella from spinach with minimal product damage.
Subject
Keyword 1 Electron beam irradiationKeyword 2 pathogen reduction
Keyword 3 spinach
Keyword 4 food safety
Keyword 5 pathogen interventions
Keyword 6 E. coli O157:H7
Keyword 7 Salmonella
Keyword 8 microbiological quality
Keyword 9 sensory evaluation
Citation
Neal, Jack A. (2009). THE EFFECTS OF ELECTRON BEAM IRRADIATION AND SANITIZERS IN THE REDUCTION OF PATHOGENS AND ATTACHMENT PREVENTION ON SPINACH. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2009 -05 -289.
Related items
Showing items related by title, author, creator and subject.
-
Nam, Chang Woo (2010-01-14)The purpose of this study was to investigate the relative effectiveness of positive interdependence and group processing on student achievement, interaction, and attitude in online cooperative learning. All of the participants, ...
-
Zheng, Yi (2010-07-14)Most bacteriophages release progeny virions at the end of the infection cycle by lysis of the host. Large phages with double-stranded DNA genomes use a multigene strategy based on holins, small membrane proteins, and ...
-
Cha, Young Jin (2010-01-14)The architectures of the control devices in active control algorithm are an important fact in civil structural buildings. Traditional research has limitations in finding the optimal architecture of control devices such as ...