Original Scientific Article
Study on factors (pH, water activity, salt content) affecting the growth of Listeria Monocytogenes in raw dried cured sausages
Daskalov Hristo * ,
Fejzullah Fejzulla ,
Stoyahchev Todor

Mac Vet Rev 2013; 36 (2): 91 - 95

637.524.065.579.869.1

Received: 30 June 2013

Received in revised form: 29 July 2013

Accepted: 22 August 2013

Available Online First: 15 October 2013

Published on: 15 October 2013

Correspondence: Daskalov Hristo, hdaskal@hotmail.com
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Abstract

Commission Regulation (EC) 2073:2005 considers the factors which can support or inhibit the growth of Listeria monocytogenesin ready-to-eat foods. The aim of the experiments was to examine the values of  pH, water activity (aw), salt content and level of contamination with Listeria monocytogenes of some popular in Bulgaria raw dried cured vacuum packed sausages, produced from June 2006 till May 2008. 81 vacuum-packed samples were taken from 5 different meat producing plants during the period of study. Average water activity level of the tested sausages was 0,87 ± 0,035; pH level - 5,61 ± 0,59 and salt content - 4,12 ± 1,11%. Four specimens contained Listeria spp. (two samples L.monocytogenes, one L.welshimeri and one L.innocua). All contaminated raw dried cured sausages had aw bellow ≤ 0,92 and pH ≥ 4,4 or pH ≥ 5. After 3 months of storage of the same contaminated samples at 40C, in three of them Listeria spp. (two L.monocitogenes and L.welshimeri) survived and was detected. Salt content of the samples varied from 2,46 to 6,28% and was not able to affect the growth of L.monocytogenes. Data showed that the detected levels of aw could support the growth of L.monocytogenes in only 6 (7,4%) of the tested samples. pH values lower than 5 were presented in three samples and only the combination with low aw was able to inhibit the growth of L.monocytogenes. The detected levels of salt content did not affect the presence and growth of L.monocytogenes. ‘Microbiological criterion’ set in COMMISSION REGULATION (EC) No 2073/2005 for ready-to-eat foods unable to support the growth of L. monocytogenescan be applied to 75 (92,6%) of the tested sausages.

Keywords: L.monocytogenes, raw dried cured sausage, water activity, pH, salt


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Copyright 

©2013 Daskalov H. This is an open-access article published under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Acknowledgement

To the Faculty of Veterinary Medicine, Trakia University, Stara Zagora, Bulgaria for sponsoring of Project 17/2006 and food processors for the help to carry out the research activities. 

Conflict of Interest Statement

The authors declared that they have no potential conflict of interest with respect to the authorship and/or publication of this article.

Citation Information

Macedonian Veterinary Review. Volume 36, Issue 2, Pages 91-95, p-ISSN 1409-7621, e-ISSN 1857-7415, 2013