560 ◾ Fundamental Food Microbiology
pathogen testing. Eventually, this technology will be able to make the lab-on-a-chip concept a
reality. In most applications, a biosensor device may find its application as a first-action screening
tool for quick results in few hours, but for confirmation, we may still have to rely on conventional
culture methods. Many of the biosensor platforms discussed above have demonstrated the proof
of concept by testing with pure bacterial cultures or toxins; however, only some select biosensors
are tested thoroughly with real-world food samples for their robustness, sensitivity, and crossreactivity. In the future, efforts should be directed toward improvement in the applicability of
most promising sensors for their effectiveness to detect foodborne pathogens from real-world food
and environmental samples. We may be a few years away from its routine usage in food safety,
food biosecurity, or food quality assessment applications. Biosensor technologies are also becoming powerful tools in biomedical applications in probing the human body for early diagnosis of
malignant cancer, cardiovascular disease, diabetes, and so forth. As we continue to embrace this
exciting field of science and technology, we will find that one day this will be an integral part of
human life, and it will impact our lifestyle.
QUESTIONS
1. Provide a general outline for isolation of foodborne bacterial cells from meat and poultry.
2. What selective enrichment broth and selective and differential agar media are used for isolation of Salmonella and Esc. coli O157:H7?
3. Discuss various methods used for separation of bacteria from food matrices.
4. Under what circumstances is the MPN method used for enumeration.
5. What is the basic principle of a biosensor, and discuss some of the advantages and disadvantages of this technology.
6. Discuss the basic operating principles of a fiber-optic biosensor and surface plasmon resonance biosensor.
7. How does a cell-based sensor work, and what physiological property of a pathogen is detected
in this sensor?
References
1. Fung, D.Y.C., Rapid methods and automation in food microbiology: A review, Food Rev. Int., 10,
357–375, 1994.
2. Vasavada, P.C., Rapid methods and automation in dairy microbiology, J. Dairy Sci., 76, 3101–3113,
1993.
3. FDA, Bacteriological Analytical Manual Online, 8th ed. AOAC International, Arlington, VA. [http://
www.fda.gov/Food/ScienceResearch/LaboratoryMethods/BacteriologicalAnalyticalManualBAM/
default.htm], 2001.
4. Downes, F.P. and Ito, K., Compendium of Methods for the Microbiological Examination of Foods, 4th Ed.,
American Public Health Association, 2001.
5. Brehm-Stecher, B., Young, C., Jaykus, L.-A., and Tortorello, M.L., Sample preparation: The forgotten
beginning J. Food Protect., 72, 1774–1789, 2009.
6. Dwivedi, H.P. and Jaykus, L.-A., Detection of pathogens in foods: The current state-of-the-art and
future directions, Crit. Rev. Microbiol., 37, 40–63, 2011.
7. Wu, V.C.H., A review of microbial injury and recovery methods in food, Food Microbiol., 25, 735–744,
2008.
8. Gracias, K.S. and McKillip, J.L., A review of conventional detection and enumeration methods for
pathogenic bacteria in food, Can. J. Microbiol., 50, 883–890, 2004.
pathogen testing. Eventually, this technology will be able to make the lab-on-a-chip concept a
reality. In most applications, a biosensor device may find its application as a first-action screening
tool for quick results in few hours, but for confirmation, we may still have to rely on conventional
culture methods. Many of the biosensor platforms discussed above have demonstrated the proof
of concept by testing with pure bacterial cultures or toxins; however, only some select biosensors
are tested thoroughly with real-world food samples for their robustness, sensitivity, and crossreactivity. In the future, efforts should be directed toward improvement in the applicability of
most promising sensors for their effectiveness to detect foodborne pathogens from real-world food
and environmental samples. We may be a few years away from its routine usage in food safety,
food biosecurity, or food quality assessment applications. Biosensor technologies are also becoming powerful tools in biomedical applications in probing the human body for early diagnosis of
malignant cancer, cardiovascular disease, diabetes, and so forth. As we continue to embrace this
exciting field of science and technology, we will find that one day this will be an integral part of
human life, and it will impact our lifestyle.
QUESTIONS
1. Provide a general outline for isolation of foodborne bacterial cells from meat and poultry.
2. What selective enrichment broth and selective and differential agar media are used for isolation of Salmonella and Esc. coli O157:H7?
3. Discuss various methods used for separation of bacteria from food matrices.
4. Under what circumstances is the MPN method used for enumeration.
5. What is the basic principle of a biosensor, and discuss some of the advantages and disadvantages of this technology.
6. Discuss the basic operating principles of a fiber-optic biosensor and surface plasmon resonance biosensor.
7. How does a cell-based sensor work, and what physiological property of a pathogen is detected
in this sensor?
References
1. Fung, D.Y.C., Rapid methods and automation in food microbiology: A review, Food Rev. Int., 10,
357–375, 1994.
2. Vasavada, P.C., Rapid methods and automation in dairy microbiology, J. Dairy Sci., 76, 3101–3113,
1993.
3. FDA, Bacteriological Analytical Manual Online, 8th ed. AOAC International, Arlington, VA. [http://
www.fda.gov/Food/ScienceResearch/LaboratoryMethods/BacteriologicalAnalyticalManualBAM/
default.htm], 2001.
4. Downes, F.P. and Ito, K., Compendium of Methods for the Microbiological Examination of Foods, 4th Ed.,
American Public Health Association, 2001.
5. Brehm-Stecher, B., Young, C., Jaykus, L.-A., and Tortorello, M.L., Sample preparation: The forgotten
beginning J. Food Protect., 72, 1774–1789, 2009.
6. Dwivedi, H.P. and Jaykus, L.-A., Detection of pathogens in foods: The current state-of-the-art and
future directions, Crit. Rev. Microbiol., 37, 40–63, 2011.
7. Wu, V.C.H., A review of microbial injury and recovery methods in food, Food Microbiol., 25, 735–744,
2008.
8. Gracias, K.S. and McKillip, J.L., A review of conventional detection and enumeration methods for
pathogenic bacteria in food, Can. J. Microbiol., 50, 883–890, 2004.