Determination of thermobacteriological parameters and size of Bacillus stearothermophilus ATCC 7953 spores


Autoria(s): Fraiha,Marcos; Ferraz,Antonio Carlos de Oliveira; Biagi,João Domingos
Data(s)

01/12/2010

Resumo

In order to determine thermobacteriological parameters for B. stearothermophilus spores, they were diluted in a saline solution medium and in ground corn-soybean mix, distributed in TDT tube, and submitted to heat for a specific period of time. The D value (time to reduce 1 log cycle of microbial count under a certain temperature) and z value (variation of temperature to cause 10-fold change in D value) were estimated. To estimate their dimensions, the spores were visualized by using a scanning electron microscope. D121.1 ºC and z values for these spores, as determined in the saline solution, were 8.8 minutes and 12.8 ºC, respectively. D121,1 ºC and z values determined in the corn-soy mix were 14.2 minutes and 23.7 ºC, respectively. The micrographs indicated that the spores have homogeneous shape and size, with length and diameter of 2 and 1 µm, respectively. These results confirm that the spore is highly thermal-resistant, and it is a good biological indicator to evaluate the extrusion process as a feed sterilizer.

Formato

text/html

Identificador

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612010000400032

Idioma(s)

en

Publicador

Sociedade Brasileira de Ciência e Tecnologia de Alimentos

Fonte

Food Science and Technology (Campinas) v.30 n.4 2010

Palavras-Chave #thermobacteriology #feed #D value #z value #spore size
Tipo

journal article