Abstract
Lethal effects of pulsed electric fields (PEF) on suspensions of various bacteria, yeast, and spores in buffer solutions and liquid foodstuffs were examined. Living-cell counts of vegetative cell types were reduced by PEF treatment by up to more than four orders of magnitude (> 99.99%). On the other hand, endoand ascospores were not inactivated or killed to any great extent. The killing of vegetative cell types depends on the electrical field strength of the pulses and on the treatment time (the product of the pulse number and the decay time constant of the pulses). For each cell type, a specific critical electric field strength (E c) and a specific critical treatment time (t c) were determined. Above these critical values, the fractions of surviving cells were reduced drastically. The “limits” E c and t c depend on the cell characteristics as well as on the type of medium in which the cells are suspended. Especially in acid media living-cell counts were sufficiently decreased at very low energy inputs. In addition to the inactivation of microorganisms, the effect of PEF on food components such as whey proteins, enzymes and vitamins, and on the taste of foodstuffs was studied. The degree of destruction of these food components by PEF was very low or negligible. Moreover, no significant deterioration of the taste of foodstuffs was detected after PEF treatment. Disintegration of cells by PEF treatment in order to harvest intracellular products was also studied. Yeast cells, suspended in buffer solution, were not disintegrated by electric pulses. Hence, PEF treatment is an excellent process for inactivation of microorganisms in acid and in thermosensive media, but not for complete disintegration of microbial cells.
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References
Adams JB (1991) Review: enzyme inactivation during heat processing of food stuffs. Int J Food Sci Technol 26: 1–20
Castberg HE, Solberg P, Egelrud T (1975) Tributyrate as a substrate fot the determination of lipase activity in milk. J Dairy Res 42: 247–253
Cooper TG (1981) Biochemische Arbeitsmethoden, Walter de Gruyter, Berlin, p 54
DIN 10 337 (Teil 1): Bestimmung der Phosphatase-Aktivität von Milch — Referenz-Verfahren. Deutsches Institut für Normung e. V. (DIN), 1977
Doevenspeck H (1960) Verfahren und Vorrichtung zur Gewinnung der einzelnen Phasen aus dispersen Systemen. DE 1 237–541
Doevenspeck H (1961) Influencing cells and cell walls by electrostatic impulses. Fleischwirtschaft 13: 986–987
Doevenspeck H (1984) Elektroimpulsverfahren und Vorrichtung zur Behandlung von Stoffen. EP 0 148 380 A3
Goldberg DM, Ellis G (1983) Isocitrate dehydrogenase. In: Bergmeyer HU (ed) Methods of enzymatic analysis, vol III. Enzymes 1: oxidoreductases, transferases, 3rd edn, VCH, Weinheim, pp 183–190
Hamilton WA, Sale AJH (1967) Effect of high electric fields on microorganisms. II. Mechanisms of action of the lethal effect. Biochim Biophys Acta 148: 789–800
Heiss R, Eichner K (1990) Haltbarmachen von Lebensmitteln: Chemische, physikalische und mikrobiologische Grundlagen der Verfahren. Springer Verlag, Berlin
Hülsheger H (1984) Wirkung elektrischer Impulse hoher Feldstärke auf Mikroorganismen in wässrigen Suspensionen. Dissertation zur Erlangung des Doktorgrades der Humanbiologie der Medizinischen Hochschule Hannover
Hülsheger H, Niemann EG (1980) Lethal effects of high voltage pulses on E. coli K12. Radiat Environ Biophys 18: 281–288
Hülsheger H, Potel J, Niemann EG (1981) Killing of bacteria with electric pulses of high field strength. Radiat Environ Biophys 20: 53–65
Hülsheger H, Potel J, Niemann EG (1983) Electric field effects on bacteria and yeast cells. Radiat Environ Biophys 22: 149–162
Husen N van, Gerlach U (1984) 5′-Nucleotidase—colorimetric method. In: Bergmeyer HU (ed) Methods of enzymatic analysis, vol IV. Enzymes 2: esterases, glycosidases, lyases, ligases. 3rd edn. VCH, Weinheim. p 106
Jacob HE, Förster W, Berg H (1981) Microbiological implications of electric field effects. II. Inactivation of yeast cells and repair of their cell envelop. Z Allg Mikrobiol 21: 255–233
Jayaram S, Castle GSP, Maragaritis A (1992) Kinetics of sterilization of Lactobacillus brevis cells by the application of high voltage pulses. Biotechnol Bioeng 40: 1412–1420
Kessler HG (1988) Lebensmittel- und Bioverfahrenstechnik — Molkereitechnologie. Verlag A. Kessler, Freising
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193: 265–275
Mertens B, Knorr D (1992) Development of nonthermal processes for food preservation. Food Technol 46: 124–133
Mizuno A, Hayamizu M (1989) Destruction of bacteria by pulsed high voltage application. In: 6th International Symposium of High Voltage Engineering, August 28–September 1, New Orleans, Mississippi State University
Mizuno A, Hori Y (1988) Destruction of living cells by pulsed high-voltage application. IEEE Transact Ind Appl 24: 387–394
Oamen EE, Hansen AP, Swartzel R (1989) Effect of ultra-high temperature steam injection processing and aseptic storage on lable water soluble vitamins in milk. J Dairy Sci 72: 614–619
Pagliarini E, Peri C, Abba S (1990a) High temperature pasteurization of milk: sensory and chemical changes. Milchwissenschaft 45: 363–366
Pagliarini E, Vernile M, Peri C (1990b) Kinetic study on color changes in milk due to heat. J Food Sci 55: 1766–1767
Sakurauchi Y, Kondo E (1980) Lethal effect of high electric fields on microorganisms. Nippon Nogeikagaku Kaishi 54: 837–844
Sale AJH, Hamilton WA (1967) Effect of high electric fields on microorganisms. I. Killing of bacteria and yeast. Biochim Biophys Acta 148: 781–788
Sale AJH, Hamilton WA (1968) Effect of high electric fields on microorganisms. III. Lysis of crythrocytes and protoplasts. Biochim Biophys Acta 163: 37–43
Sato M (1989) Sterilization by pulsed electric field. Kagaku Kougaku 53: 818–819
Sato M, Tokita K, Sadaka M, Sakai T, Nakanishi K (1988) Sterilization of microorganisms by high-voltage pulsed discharge under water. Kagaku Kougaku Ronbunshu 14: 556–559
Sitzmann W, Münch EW (1989) Elektrische Verfahren zur Keimabtötung. Ernährungs industrie 6: 54–58
Steinau M (1992) Berechnung des zeitlichen Verlaufs eines elektrischen Hochspannungs impulses. Studie, Arbeitsbereich Biotechnologie I, Technische Universität Hamurg-Harburg
Stellmach B (1988) Peroxidase. In: Bestimmungsmethoden Enzyme für Pharmazie, Lebensmittelchemie, Technik, Biochemie, Biologie Medizin. Steinkopff, Darmstadt, p 217
Stürken K (1989) Konstruktion einer Hochspannungsküvettezum Abtöten von Mikroorganismen. Diplomarbeit, Arbeitsbereich Biotechnologie I, Technische Universität Hamburg-Harburg, P 15
Süssmuth R, Eberspaecher J, Haag R, Springer W (1987) Biochemisch-mikrobiologisches Praktikum. Thieme, Stuttgart, p 317
Vassault A (1983) Lactate dehydrogenase. In: Bergmeyer HU (ed). Methods of enzymatic analysis, vol III. Enzymes 1: oxidoreductases, transferases. 3rd edn. VCH, Weinheim, p 118
Versaw Wk, Cuppett SL, Winters D, Williams LE (1989) An improved colorimetric method for bacterial lipase in nonfat dry milk. J Food Sci 54: 1557–1568
Zimmermann U (1986) Electrical breakdown, electropermeabilization and electrofusion. Rev Physiol Biochem Pharmacol 105: 175–256
Zimmermann U, Benz R (1980) Dependence of the electrical breakdown voltage on the charging time in Valonia utricularis. J Membr Biol 53: 33–43
Zimmermann U, Arnod WM, Mehrle W (1988) Biophysics of electroinjection and electrofusion. J Electrostat 21: 309–345
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Grahl, T., Märkl, H. Killing of microorganisms by pulsed electric fields. Appl Microbiol Biotechnol 45, 148–157 (1996). https://doi.org/10.1007/s002530050663
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DOI: https://doi.org/10.1007/s002530050663