Comparative study on the high pressure inactivation behavior of the Shiga toxin-producing Escherichia coli O104:H4 and O157:H7 outbreak strains and a non-pathogenic surrogate.
Food Microbiol
; 46: 184-194, 2015 Apr.
Article
en En
| MEDLINE
| ID: mdl-25475283
ABSTRACT
Enterohemorrhagic Escherichia coli strains cause each year thousands of illnesses, which are sometimes accompanied by the hemolytic uremic syndrome, like in the 2011 outbreak in Germany. For preservation thermal pasteurization is commonly used, which can cause unwanted quality changes. To prevent this high pressure treatment is a potential alternative. Within this study, the 2011 outbreak strain O104H4, an O157H7 and a non-pathogenic strain (DSM1116) were tested. The cells were treated in buffer (pH 7 and pH 5) and carrot juice (pH 5.1) in a pressure temperature range of 0.1-500 MPa and 20-70 °C. Flow cytometry was used to investigate the pressure impact on cell structures of the strain DSM1116. Both pathogenic strains had a much higher resistance in buffer and carrot juice than the non-pathogenic surrogate. Further, strains cultivated and treated at a lower pH-value showed higher pressure stability, presumably due to variations in the membrane composition. This was confirmed for the strain DSM1116 by flow cytometry. Cells cultivated and treated at pH 5 had a stronger ability to retain their membrane potential but showed higher rates of membrane permeabilization at pressures <200 MPa compared to cells cultivated and treated at pH 7. These cells had the lowest membrane permeabilization rate at around 125 MPa, possibly denoting that variations in the fatty acid composition and membrane fluidity contribute to this stabilization phenomenon.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Bebidas
/
Infecciones por Escherichia coli
/
Escherichia coli Shiga-Toxigénica
Límite:
Humans
País/Región como asunto:
Europa
Idioma:
En
Revista:
Food Microbiol
Asunto de la revista:
CIENCIAS DA NUTRICAO
/
MICROBIOLOGIA
Año:
2015
Tipo del documento:
Article