Inactivation of Escherichia coli O157:H7 on lettuce, using low-energy X-ray irradiation.
J Food Prot
; 73(3): 547-51, 2010 Mar.
Article
em En
| MEDLINE
| ID: mdl-20202343
ABSTRACT
Low-energy X-ray irradiation was assessed as a means of eliminating Escherichia coli O157H7 on lettuce. Round-cut iceberg lettuce samples (2.54-cm diameter) were dip or spot inoculated with a three-strain cocktail of E. coli O157H7, stored for 24 h at 4 degrees C, and then irradiated at four dose levels up to 0.25 kGy using a prototype low-energy (70 kV) X-ray irradiator. E. coli O157H7 survivors were quantified by plating on sorbitol MacConkey agar containing cefixime and tellurite. Dip inoculation yielded a D(10)-value of 0.040 +/- 0.001 kGy, which is 3.4 times lower than a previously reported value of 0.136 kGy using gamma radiation. The D(10)-value for E. coli O157H7 on spot-inoculated samples was 0.078 +/- 0.008 kGy, which is about twice that of dip-inoculated samples. When 10 stacked leaves were irradiated from both sides, a dose of 0.2 kGy was achieved at the center of the stack with a surface dose of 1 kGy, corresponding to a approximately 5-log reduction of E. coli O157H7 at the center of the stack. Based on these findings, low-energy X-ray irradiation appears to be a promising microbial inactivation strategy for leafy greens and potentially for other types of fresh produce.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Lactuca
/
Escherichia coli O157
/
Irradiação de Alimentos
Limite:
Humans
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article