TY - JOUR
T1 - Cold and carbon dioxide used as multi-hurdle preservation do not induce appearance of viable but non-culturable Listeria monocytogenes
AU - Li, J.
AU - Kolling, G. L.
AU - Matthews, K. R.
AU - Chikindas, Michael L.
PY - 2003
Y1 - 2003
N2 - Aims: To study whether the exposure to cold (4°C) and carbon dioxide which results in the elongation of Listeria cells, induces a viable but nonculturable (VBNC) state. Methods and Results: When cold and CO2 stressed L. monocytogenes were observed under a fluorescence microscope, using the LIVE/DEAD BacLight® bacteria viability kit (Molecular Probes, Eugene, OR, USA), the healthy, mildly injured, and the putative VBNC cells accounted for 31.0% of the stressed cell population. By using the selective plate count, 31.4% of the same stressed cell population was found to be healthy and mildly injured (putative VBNC cells not included). If there were VBNC state cells present, we should have observed a significant difference between the above two numbers. In fact, there was no significant difference between the results obtained from those two methods. Conclusions: There were no VBNC state cells observed in the stressed cell population. We conclude that cold and CO2 do not induce L. monocytogenes to enter a VBNC state. Significance and Impact of the Study: Cold and modified atmospheres are widely used in fresh muscle food and fruit preservation. Whether they would induce L. monocytogenes into a VBNC state is of a great concern for microbial food safety.
AB - Aims: To study whether the exposure to cold (4°C) and carbon dioxide which results in the elongation of Listeria cells, induces a viable but nonculturable (VBNC) state. Methods and Results: When cold and CO2 stressed L. monocytogenes were observed under a fluorescence microscope, using the LIVE/DEAD BacLight® bacteria viability kit (Molecular Probes, Eugene, OR, USA), the healthy, mildly injured, and the putative VBNC cells accounted for 31.0% of the stressed cell population. By using the selective plate count, 31.4% of the same stressed cell population was found to be healthy and mildly injured (putative VBNC cells not included). If there were VBNC state cells present, we should have observed a significant difference between the above two numbers. In fact, there was no significant difference between the results obtained from those two methods. Conclusions: There were no VBNC state cells observed in the stressed cell population. We conclude that cold and CO2 do not induce L. monocytogenes to enter a VBNC state. Significance and Impact of the Study: Cold and modified atmospheres are widely used in fresh muscle food and fruit preservation. Whether they would induce L. monocytogenes into a VBNC state is of a great concern for microbial food safety.
KW - Carbon dioxide
KW - Cold
KW - Elongation
KW - Listeria
KW - Viable but non-culturable stress
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U2 - https://doi.org/10.1046/j.1365-2672.2003.01795.x
DO - https://doi.org/10.1046/j.1365-2672.2003.01795.x
M3 - Article
C2 - 12492922
VL - 94
SP - 48
EP - 53
JO - Journal of Applied Microbiology
JF - Journal of Applied Microbiology
SN - 1364-5072
IS - 1
ER -