Electrical Impedance Method for Determining Microbial Quality of Foods

  • R. Firstenberg-Eden

Abstract

Impedance is the opposition to flow of an alternating electrical current in a conducting material. When monitoring the growth of microorganisms, the conducting material is a microbiological medium. Impedance changes occur in the medium as its chemical composition changes due to growth and metabolic activity of microorganisms. During growth, microorganisms convert larger molecules to smaller, more mobile metabolites, thus changing the impedance. When the microbial population reaches a threshold fo 106–107 cells/ml an exponential change in impedance signal is observed. The time required for this exponential change is inversely proportional to the initial cell concentration and is defined as impedance detection time (IDT)

Keywords

Biomass Agar Hydroxide Pseudomonas Staphylococcus 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Bishop JR, White CH, Firstenberg-Eden R (1984) A rapid impedimetric method for determining the potential shelf-life of pasteurized whole milk. J Food Prot 47 (6):471–475Google Scholar
  2. Firstenberg-Eden R (1983) Rapid estimation of the number of microorganisms in raw meat by impedance measurements. Food Technol 37:64–70Google Scholar
  3. Firstenberg-Eden R (1984) A collaborative study of the impedance method for examining raw milk samples. J Food Prot 47 (9):707–712Google Scholar
  4. Firstenberg-Eden R, Klein CS (1983) Evaluation of a rapid impedimetric procedure for the quantitative estimation of coliforms. J Food Sci 48:1307–1311CrossRefGoogle Scholar
  5. Firstenberg-Eden R, Tricarico MK (1983) Impedimetric determination of total, mesophilic and psychrotrophic counts in raw milk. J Food Sci 48:1307–1311CrossRefGoogle Scholar
  6. Firstenberg-Eden R, Zindulis J (1984) Electrochemical changes in media due to microbial growth. J Microbiol Methods 2:103–115CrossRefGoogle Scholar
  7. Firstenberg-Eden R, VanSise ML, Klein CS (1983) An impedimetric method for the presumptive identification of Salmonella. IFT 1983 Abstract 346, New OrleansGoogle Scholar
  8. Hadley D, Kraeger SJ, Dufour SW, Cady P (1977) Rapid detection of microbial contamination in frozen vegetables by automated impedance measurements. Appl on microbiol 34:14–17Google Scholar
  9. Schwan HP (1963) Dtermination of biological impedance in WL (ed) Physical techniques in biological research, vol VI Electrophysiogical methods. Part B Academic Press, New York, p 323Google Scholar
  10. Sharpe AN (1979) Germ of a new food microbiology. New Scientist 13:860–862Google Scholar
  11. Soagaard H, Lund R (1981) Psychrotrophic in raw milk and the keeping quality of pasteurized milk products. In: Psychrotrophic microorganisms in spoilage and pathogenicity. Academic, New York, p 91Google Scholar
  12. Zall RR, Chen JH, Murphy SC (1982) The detection of psychrotrophic bacteria in milk using a dye test. Cult Dairy Prod J 17:7–12Google Scholar
  13. Zindulis J (1984) A medium for the impedimetric detection of yeasts in foods. Food Microbiology 1:159–167CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1985

Authors and Affiliations

  • R. Firstenberg-Eden
    • 1
  1. 1.Bactomatic Inc.PrincetonUSA

Personalised recommendations