524 ◾ Fundamental Food Microbiology
should be evaluated by the isolation technique. The results also showed that pressurization in the
presence of a suitable antimicrobial (such as a bacteriocin mixture) is more effective in reducing
foodborne bacteria.
Conclusion
To meet consumer demand, several thermal and nonthermal technologies are being studied for
the processing of foods. Among these, Plasma technology, PEF and HPP, especially the HPP
technology, offer a great potential. Both technologies are nonthermal methods and suitable for
the production of pasteurized food. HPP, however, in combination with high heat, can be used to
produce commercially sterile foods that have a better acceptance quality than that of foods produced by the comparable thermal process. HPP can also be used to produce novel foods and novel
processing techniques. Other parameters can be used with many of these technologies to provide
an added advantage. This concept is discussed in Chapter 41 as the hurdle concept.
QUESTIONS
1. List two thermal and four nonthermal processes among the currently studied technologies
for application in food processing and preservation. What advantages do they have over the
conventional methods now being used?
2. Briefly describe the principles of the antimicrobial actions of the four nonthermal processes,
other than PEF and HPP, listed in this chapter.
3. Briefly discuss the mechanisms of antimicrobial action of PEF technology and how this is
being used to improve preservation of foods.
4. Discuss why HPP treatment does not adversely affect the food quality.
5. Describe six other applications of HPP in food processing besides preservation and discuss
the advantages of the methods in these applications.
6. Discuss the mechanisms of antimicrobial action of HPP against the vegetative cells of
microorganisms.
7. Discuss the problems associated with the sublethal injury and resistance of foodborne pathogens in pressure-processed foods.
8. Discuss the mechanisms by which foodborne bacterial spores can be destroyed at low and
high hydrostatic pressure.
9. Define pressure pasteurization and pressure sterilization of food and discuss their differences
from pasteurization and commercial sterilization of food by heat treatment.
10. List eight foods from four food groups that have been studied for microbial control in HPP.
References
1. Miller, S.A., Science, law and society: The pursuit of food safety, J. Nutr., 123, 279–284, 1993.
2. Pereira, R.N. and Vicente, A.A., Environmental impact of novel thermal and non-thermal technologies
in food processing, Food Res. Int., 43, 1936–1943, 2010.
3. Goodburn, C. and Wallace, C.A., The microbiological efficacy of decontamination methodologies for
fresh produce: A review, Food Control, 32, 418–427, 2013.
should be evaluated by the isolation technique. The results also showed that pressurization in the
presence of a suitable antimicrobial (such as a bacteriocin mixture) is more effective in reducing
foodborne bacteria.
Conclusion
To meet consumer demand, several thermal and nonthermal technologies are being studied for
the processing of foods. Among these, Plasma technology, PEF and HPP, especially the HPP
technology, offer a great potential. Both technologies are nonthermal methods and suitable for
the production of pasteurized food. HPP, however, in combination with high heat, can be used to
produce commercially sterile foods that have a better acceptance quality than that of foods produced by the comparable thermal process. HPP can also be used to produce novel foods and novel
processing techniques. Other parameters can be used with many of these technologies to provide
an added advantage. This concept is discussed in Chapter 41 as the hurdle concept.
QUESTIONS
1. List two thermal and four nonthermal processes among the currently studied technologies
for application in food processing and preservation. What advantages do they have over the
conventional methods now being used?
2. Briefly describe the principles of the antimicrobial actions of the four nonthermal processes,
other than PEF and HPP, listed in this chapter.
3. Briefly discuss the mechanisms of antimicrobial action of PEF technology and how this is
being used to improve preservation of foods.
4. Discuss why HPP treatment does not adversely affect the food quality.
5. Describe six other applications of HPP in food processing besides preservation and discuss
the advantages of the methods in these applications.
6. Discuss the mechanisms of antimicrobial action of HPP against the vegetative cells of
microorganisms.
7. Discuss the problems associated with the sublethal injury and resistance of foodborne pathogens in pressure-processed foods.
8. Discuss the mechanisms by which foodborne bacterial spores can be destroyed at low and
high hydrostatic pressure.
9. Define pressure pasteurization and pressure sterilization of food and discuss their differences
from pasteurization and commercial sterilization of food by heat treatment.
10. List eight foods from four food groups that have been studied for microbial control in HPP.
References
1. Miller, S.A., Science, law and society: The pursuit of food safety, J. Nutr., 123, 279–284, 1993.
2. Pereira, R.N. and Vicente, A.A., Environmental impact of novel thermal and non-thermal technologies
in food processing, Food Res. Int., 43, 1936–1943, 2010.
3. Goodburn, C. and Wallace, C.A., The microbiological efficacy of decontamination methodologies for
fresh produce: A review, Food Control, 32, 418–427, 2013.