Control by Low Temperature ◾ 465
QUESTIONS
1. List the microbiological objectives of low-temperature preservation of food. How do these
objectives differ from those for food preserved by heat?
2. Briefly discuss the mechanisms of microbial control by reducing the temperature of a food
to 10°C, to –1°C, to –10°C, and to –20°C.
3. List the major factors that need to be considered for effective control of microorganisms in
a food at low temperatures and briefly discuss the importance of each.
4. Discuss the microbial implications of the following in low-temperature preservation of
foods: (a) fluctuation of storage (refrigerated and frozen) temperature, (b) slow cooling of a
warm food, and (c) slow thawing of a frozen food.
5. Briefly discuss the microbiological problems of foods stored by chilling, refrigeration, and
freezing.
6. List the psychrotrophic pathogens that can cause a food hazard in refrigerated ready-to-eat
foods and suggest a method that can be used to overcome the problem (consult Chapter 41).
References
1. Tassou, S.A., Lewis, J.S., Ge, Y.T., Hadawey, A., and Chaer, I., A review of emerging technologies for
food refrigeration applications, Appl. Therm. Eng., 30, 263–276, 2010.
2. Beales, N., Adaptation of microorganisms to cold temperatures, weak acid preservatives, low pH, and
osmotic stress: A review, Comp. Rev. Food Sci. Food Safety, 3, 1–20, 2004.
3. 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.
4. Ray, B., Injured Index and Pathogenic Bacteria, CRC Press, Boca Raton, FL, 1989.
5. Zhou, G.H., Xu, X.L., and Liu, Y., Preservation technologies for fresh meat: A review, Meat Sci., 86,
119–128, 2010.
6. Kaale, L.D., Eikevik, T.M., Rustad, T., and Kolsaker, K., Superchilling of food: A review, J. Food Eng.,
107, 141–146, 2011.
QUESTIONS
1. List the microbiological objectives of low-temperature preservation of food. How do these
objectives differ from those for food preserved by heat?
2. Briefly discuss the mechanisms of microbial control by reducing the temperature of a food
to 10°C, to –1°C, to –10°C, and to –20°C.
3. List the major factors that need to be considered for effective control of microorganisms in
a food at low temperatures and briefly discuss the importance of each.
4. Discuss the microbial implications of the following in low-temperature preservation of
foods: (a) fluctuation of storage (refrigerated and frozen) temperature, (b) slow cooling of a
warm food, and (c) slow thawing of a frozen food.
5. Briefly discuss the microbiological problems of foods stored by chilling, refrigeration, and
freezing.
6. List the psychrotrophic pathogens that can cause a food hazard in refrigerated ready-to-eat
foods and suggest a method that can be used to overcome the problem (consult Chapter 41).
References
1. Tassou, S.A., Lewis, J.S., Ge, Y.T., Hadawey, A., and Chaer, I., A review of emerging technologies for
food refrigeration applications, Appl. Therm. Eng., 30, 263–276, 2010.
2. Beales, N., Adaptation of microorganisms to cold temperatures, weak acid preservatives, low pH, and
osmotic stress: A review, Comp. Rev. Food Sci. Food Safety, 3, 1–20, 2004.
3. 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.
4. Ray, B., Injured Index and Pathogenic Bacteria, CRC Press, Boca Raton, FL, 1989.
5. Zhou, G.H., Xu, X.L., and Liu, Y., Preservation technologies for fresh meat: A review, Meat Sci., 86,
119–128, 2010.
6. Kaale, L.D., Eikevik, T.M., Rustad, T., and Kolsaker, K., Superchilling of food: A review, J. Food Eng.,
107, 141–146, 2011.