<abstract xmlns="http://www.w3.org/1999/xhtml">

 This study describes preparation of test samples composed of freeze-dried strain of <italic>S. aureus </italic>and powdered milk as a matrix. In the first part of the study, the number of <italic>S. aureus </italic>cells freeze-dried in skim milk or horse serum were compared at two levels of contamination (104 and 105 cfu g-1). The analysis of the samples was performed three times within a week. The preliminary results showed that the samples composed of <italic>S. aureus </italic>freeze-dried in horse serum were more stable and homogeneous than those prepared with skim milk. These results were further confirmed after analysing a higher number of such samples. Therefore, this procedure was then chosen for preparation of the samples for proficiency tests (PTs). Homogeneity and stability of these samples were checked according to ISO 13528. The results obtained showed that the samples met the criteria of stability and homogeneity required for PTs and were used in PT for enumeration of <italic>S. aureus </italic>in powdered milk.
</abstract>

This study describes preparation of test samples composed of freeze-dried strain of S. aureus and powdered milk as a matrix. In the first part of the study, the number of S. aureus cells freeze-dried in skim milk or horse serum were compared at two levels of contamination (104 and 105 cfu g-1). The analysis of the samples was performed three times within a week. The preliminary results showed that the samples composed of S. aureus freeze-dried in horse serum were more stable and homogeneous than those prepared with skim milk. These results were further confirmed after analysing a higher number of such samples. Therefore, this procedure was then chosen for preparation of the samples for proficiency tests (PTs). Homogeneity and stability of these samples were checked according to ISO 13528. The results obtained showed that the samples met the criteria of stability and homogeneity required for PTs and were used in PT for enumeration of S. aureus in powdered milk.

Homogeneity and Stability of Samples Used for Proficiency Testing in Enumeration of Coagulase Positive Staphylococci

Department of Hygiene of Food of Animal Origin

Journal of Veterinary Research

This study describes preparation of test samples composed of freeze-dried strain of S. aureus and powdered milk as a matrix. In the first part of the study,...

Homogeneity and Stability of Samples Used for Proficiency Testing in Enumeration of Coagulase Positive Staphylococci

Publicado en línea: 17 ene 2013

Páginas: 559 - 562

DOI: https://doi.org/10.2478/v10213-012-0098-x

Palabras clave
S. aureus, homogeneity, stability, proficiency testing

This content is open access.

Homogeneity and Stability of Samples Used for Proficiency Testing in Enumeration of Coagulase Positive Staphylococci

Publicado en línea: 17 ene 2013

Páginas: 559 - 562

DOI: https://doi.org/10.2478/v10213-012-0098-x

Palabras claveS. aureus, homogeneity, stability, proficiency testing

This content is open access.

Palabras clave
S. aureus, homogeneity, stability, proficiency testing