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Influence of UHP Treatment on Survival of Yesinia Enterocolitica

Bożena Windyga 1Halina Scieżyńska 1A. Grochowska 1Krystyna Górecka 1Monika Fonberg-Broczek 1,2K. Karłowski 1Jacek Arabas 2Janusz Szczepek 2

1. National Institute of Hygiene, Warszawa, Poland
2. Polish Academy of Sciences, High Pressure Research Center (UNIPRESS), Sokolowska 29/37, Warszawa 01-142, Poland


Yersinia enterocolitica was added to the list of foodborne pathogenic
micro-organisms . Yersinia is a typical member of the
Enterobacteriaceae, is "low temperature" and are able to grow at
40 C and perfectly survive long periods in frozen conditions.
Foods products (ham, tofu, chocolate milk, vegetable salad) kept in
refrigerating conditions, especially those vacuum-packed, can be
caused foodborne outbreak of yersiniosis. Cooling and freezing methods
used on a large scale and a then use of microwaves for preparation of
meals, often of a limited used kitchen salt, preservative, and acidity
favours the survival and grow of such micro-organisms like Y.
The effect of hydrostatic pressure ( UHP ) and dose of albumine on
cultures of Yersinia enterocolitica in saline solution was

Materials and methods Y. enterocolitica
serovar 05 was isolated from pork heart. The colony count of
microorganisms in control samples was 7,5 x 107 cfu/ml. 5 ml of
culture was treated at hydrostatic pressure from 100 to 400 MPa for 10
minutes. The applied doses of albumine were 0%, 0,3%, 1%, 5% and 10%.
The experiments was carried out at room temperatute in High Pressure
Research Center, Polish Academy of Science. The pressure increase up
to the required level in 30 - 60 secunds and depressurisation was done
in 60 secunds.

Pressure of 100 and 200MPa did not decrease number of bacteria ( cfu )
in all of the investigated samples. Presure of 300MPa for each
albumine and fat level was sufficient for killing all cells of Y.
The study proved that the levels of 20% and 40% of sugar in fruit
juices and concentrates had baroprotective effect on survival rate of
Yersinia enterocolitica, 3% NaCL solution as a culture medium
increased sensibility of Y. enterocolitica to High Pressure treatment.
There was no observed baroprotective effect of adition to the sample
medium of albumin and different fat levels in milk cream on survival
rate of Yersinia enterocolitica.


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Related papers

Presentation: poster at High Pressure School 1999 (3rd), by Monika Fonberg-Broczek
See On-line Journal of High Pressure School 1999 (3rd)

Submitted: 2003-02-16 17:33
Revised:   2009-06-08 12:55