114 ◾ Fundamental Food Microbiology
Controlled cells: NSA: 3 × 10 7 and SA: 2.8 × 10 7
Stressed cells: NSA: 0.5 × 10 7 and SA: 6 × 10 5
Repaired cells: NSA: 0.5 × 10 7 and SA: 3 × 10 6
Calculate the percentage of dead, injured, normal, repaired, and unrepaired cells.
9. List the importance of sublethal injury in food microbiology and explain how the phenomenon can be used in problem solving and for beneficial purposes.
10. Define the phenomenon of VBNC of bacterial cells. Explain the importance of the
phenomenon.
11. Briefly list the findings and suggestions of the proponent groups on the VBNC phenomenon.
12. List the views of the opponent groups against the existence of the VBNC phenomenon.
13. Explain briefly the suggestions that could be associated with the so-called VBNC phenomenon in light of some recent findings.
14. How justified is the assumption that stress adaptation, sublethal injury, and the VBNC state
can be grouped together as different manifestations of bacterial cells under different levels or
degrees of stress?
15. Define or explain the importance of the following terms (in food microbiology): stress protein; sigma factors; holoenzyme (RNA polymerase); loss of divalent cations of LPS layer;
conformational alteration of structural and functional components under stress; spore
injury; survival strategy of VBNC cells; culturability and nonculturability.
References
1. Ray, B. Injured Index and Pathogenic Bacteria, CRC Press, Boca Raton, FL, 1989.
2. Andrew, M.H.E. and Russell, A.D., The Revival of Injured Microbes, Academic Press, Orlando, FL,
1984.
3. Hurst, A. and Nasim, A., Repairable Lesions in Microorganisms, Academic Press, Orlando, FL, 1984.
4. Colwell, R.R. and Grimes, D.J., Nonculturable Microorganisms in the Environment, ASM Press,
Washington, DC, 1995.
5. Yousef, A.E. and Juneja, V.K., Microbial Stress Adaptation and Food Safety, CRC Press, Boca Raton, FL,
2003.
6. Wesche, A.M., Gurtler, J.B., Marks, B.P., and Ryser, E.T., Stress, sublethal injury, resuscitation, and
virulence of bacterial foodborne pathogens, J. Food Prot., 72, 1121–1138, 2009.
7. Angelis, M. and Gobbetti, M., Stress responses of lactobacilli. In Stress Responses of Lactic Acid Bacteria,
Tsakalidou, E. and Papadimitriou, K., Eds., Springer US, 2011, 219–249.
8. Aertsen, A. and Michiels, C.W., Stress and how bacteria cope with death and survival, Crit. Rev.
Microbiol., 30, 263–273, 2004.
9. Shen, S. and Fang, F.C., Integrated stress responses in Salmonella, Int. J. Food Microbiol., 152, 75–81,
2012.
10. Battesti, A., Majdalani, N., and Gottesman, S., The RpoS-mediated general stress response in Escherichia
coli, Annu. Rev. Microbiol., 65, 189–213, 2011.
11. Álvarez-Ordóñez, A., Prieto, M., Bernardo, A., Hill, C., and López, M., The acid tolerance response of
Salmonella spp.: An adaptive strategy to survive in stressful environments prevailing in foods and the
host, Food Res. Int., 45, 482–492, 2012.
12. Milillo, S.R., Friedly, E.C., Saldivar, J.C., Muthaiyan, A., O’Bryan, C., Crandall, P.G., Ricke, S.C. et
al., A review of the ecology, genomics, and stress response of Listeria innocua and Listeria monocytogenes,
Crit. Rev. Food Sci. Nutr., 52, 712–725, 2012.
Controlled cells: NSA: 3 × 10 7 and SA: 2.8 × 10 7
Stressed cells: NSA: 0.5 × 10 7 and SA: 6 × 10 5
Repaired cells: NSA: 0.5 × 10 7 and SA: 3 × 10 6
Calculate the percentage of dead, injured, normal, repaired, and unrepaired cells.
9. List the importance of sublethal injury in food microbiology and explain how the phenomenon can be used in problem solving and for beneficial purposes.
10. Define the phenomenon of VBNC of bacterial cells. Explain the importance of the
phenomenon.
11. Briefly list the findings and suggestions of the proponent groups on the VBNC phenomenon.
12. List the views of the opponent groups against the existence of the VBNC phenomenon.
13. Explain briefly the suggestions that could be associated with the so-called VBNC phenomenon in light of some recent findings.
14. How justified is the assumption that stress adaptation, sublethal injury, and the VBNC state
can be grouped together as different manifestations of bacterial cells under different levels or
degrees of stress?
15. Define or explain the importance of the following terms (in food microbiology): stress protein; sigma factors; holoenzyme (RNA polymerase); loss of divalent cations of LPS layer;
conformational alteration of structural and functional components under stress; spore
injury; survival strategy of VBNC cells; culturability and nonculturability.
References
1. Ray, B. Injured Index and Pathogenic Bacteria, CRC Press, Boca Raton, FL, 1989.
2. Andrew, M.H.E. and Russell, A.D., The Revival of Injured Microbes, Academic Press, Orlando, FL,
1984.
3. Hurst, A. and Nasim, A., Repairable Lesions in Microorganisms, Academic Press, Orlando, FL, 1984.
4. Colwell, R.R. and Grimes, D.J., Nonculturable Microorganisms in the Environment, ASM Press,
Washington, DC, 1995.
5. Yousef, A.E. and Juneja, V.K., Microbial Stress Adaptation and Food Safety, CRC Press, Boca Raton, FL,
2003.
6. Wesche, A.M., Gurtler, J.B., Marks, B.P., and Ryser, E.T., Stress, sublethal injury, resuscitation, and
virulence of bacterial foodborne pathogens, J. Food Prot., 72, 1121–1138, 2009.
7. Angelis, M. and Gobbetti, M., Stress responses of lactobacilli. In Stress Responses of Lactic Acid Bacteria,
Tsakalidou, E. and Papadimitriou, K., Eds., Springer US, 2011, 219–249.
8. Aertsen, A. and Michiels, C.W., Stress and how bacteria cope with death and survival, Crit. Rev.
Microbiol., 30, 263–273, 2004.
9. Shen, S. and Fang, F.C., Integrated stress responses in Salmonella, Int. J. Food Microbiol., 152, 75–81,
2012.
10. Battesti, A., Majdalani, N., and Gottesman, S., The RpoS-mediated general stress response in Escherichia
coli, Annu. Rev. Microbiol., 65, 189–213, 2011.
11. Álvarez-Ordóñez, A., Prieto, M., Bernardo, A., Hill, C., and López, M., The acid tolerance response of
Salmonella spp.: An adaptive strategy to survive in stressful environments prevailing in foods and the
host, Food Res. Int., 45, 482–492, 2012.
12. Milillo, S.R., Friedly, E.C., Saldivar, J.C., Muthaiyan, A., O’Bryan, C., Crandall, P.G., Ricke, S.C. et
al., A review of the ecology, genomics, and stress response of Listeria innocua and Listeria monocytogenes,
Crit. Rev. Food Sci. Nutr., 52, 712–725, 2012.