Premium
Growth of Listeria monocytogenes and Yersinia enterocolitica colonies under modified atmospheres at 4 and 8 °C using a model food system
Author(s) -
Harrison W. A.,
Peters A. C.,
Fielding L. M.
Publication year - 2000
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2000.00848.x
Subject(s) - yersinia enterocolitica , listeria monocytogenes , food science , microbiology and biotechnology , listeria , biology , food microbiology , bacteria , chemistry , genetics
W.A. HARRISON, A.C. PETERS and L.M. FIELDING.2000. The growth of Listeria monocytogenes and Yersinia enterocolitica colonies was studied on solid media at 4 and 8 °C under modified atmospheres (MAs) of 5% O 2 : 10% CO 2 : 85% N 2 (MA 1 ), 30% CO 2 : 70% N 2 (MA 2 ) and air (control). Colony radius, determined using computer image analysis, allowed specific growth rates (μ) and the time taken to detect bacterial colonies to be estimated, after colonies became visible. At 4 °C both MAs decreased the growth rates of L. monocytogenes by 1·5‐ and 3·0‐fold under MA 1 (μ = 0·02 h −1 ) and MA 2 (μ = 0·01 h −1 ), respectively, as compared with the control (μ = 0·03 h −1 ). The time to detection of bacterial colonies was increased from 15 d (control) to 24 (MA 1 ) and 29 d (MA 2 ). At 8 °C MA 2 decreased the growth rate by 1·5‐fold (μ = 0·04 h −1 ) as compared with the control (μ = 0·06 h −1 ) and detection of colonies increased from 7 (control) to 9 d (MA 2 ). At 4 °C both MAs decreased the growth rates of Y. enterocolitica by 1·5‐ and 2·5‐fold under MA 1 (μ = 0·03 h −1 ) and MA 2 (μ = 0·02 h −1 ), respectively, as compared with the control (μ = 0·05 h −1 ). At 8 °C identical growth rates were obtained under MA 1 and the control (μ = 0·07 h −1 ) whilst a decrease in the growth rate was obtained under MA 2 (μ = 0·04 h −1 ). The detection of colonies varied from 6 (8 °C, aerobic) to 19 d (4 °C, MA 2 ). Refrigerated modified atmosphere packaged foods should be maintained at 4 °C and below to ensure product safety.