German
English
Thursday, May 17, 2012
Abstracts from 
Fleischwirtschaft 91 (10), S. 97 -101, 2011
Evaluation of a novel agar medium for the detection of hydrogen peroxide producing lactic acid bacteria
By Lothar Kröckel
starter and protective cultures | lactic acid bacteria | peroxide producers | bacteriocin producers | hydrogen peroxide | prepackaged sliced Bologna-type sausage | Prussian Blue agar | manganese dioxide agar
(original article is only in German language available)
The demonstration of hydrogen peroxide formation by meat-borne lactic acid bacteria is of considerable importance for the characterization of individual strains, the selection of suitable starter and protective cultures for various applications for meat and meat products as well as for the search of potential microbiological causes for undesired sensory deviations. In the present study, a recently introduced novel agar medium (‘Prussian Blue' Agar) was applied for the first time to lactic acid bacteria relevant to meat and meat products. The PB agar detects H2O2 through the formation of Prussian Blue. It principally delivers similar results as the traditional manganese dioxide agar. However, it is more sensitive, and it is also easily prepared and delivers results more quickly. A representative number of strains was used in the evaluation of the new medium.
As to the production of H2O2, the study revealed large differences within the Lactobacillus sakei/curvatus group. The bacteriocin producers frequently seemed to be relatively weak peroxide producers, while many commercial starter cultures were recognized as more or
less strong peroxide producers. More recent field isolates of Lactobacillus sakei/curvatus from prepackaged sliced Bologna-type sausage gave an essentially similar picture. In this case, however, only one of ten isolates of Lb. curvatus gave rise to a positive reaction.
Author's address
Dr. Lothar Kröckel, Max-Rubner-Institut, Institut für Sicherheit und Qualität bei Fleisch,
E.-C.-Baumann-Straße 20, 95326 Kulmbach
The demonstration of hydrogen peroxide formation by meat-borne lactic acid bacteria is of considerable importance for the characterization of individual strains, the selection of suitable starter and protective cultures for various applications for meat and meat products as well as for the search of potential microbiological causes for undesired sensory deviations. In the present study, a recently introduced novel agar medium (‘Prussian Blue' Agar) was applied for the first time to lactic acid bacteria relevant to meat and meat products. The PB agar detects H2O2 through the formation of Prussian Blue. It principally delivers similar results as the traditional manganese dioxide agar. However, it is more sensitive, and it is also easily prepared and delivers results more quickly. A representative number of strains was used in the evaluation of the new medium.
As to the production of H2O2, the study revealed large differences within the Lactobacillus sakei/curvatus group. The bacteriocin producers frequently seemed to be relatively weak peroxide producers, while many commercial starter cultures were recognized as more or
less strong peroxide producers. More recent field isolates of Lactobacillus sakei/curvatus from prepackaged sliced Bologna-type sausage gave an essentially similar picture. In this case, however, only one of ten isolates of Lb. curvatus gave rise to a positive reaction.
Author's address
Dr. Lothar Kröckel, Max-Rubner-Institut, Institut für Sicherheit und Qualität bei Fleisch,
E.-C.-Baumann-Straße 20, 95326 Kulmbach
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