Inactivation of Listeria innocua inoculated in liquid whole egg by high hydrostatic pressure.
The resistance of Listeria innocua, as a model microorganism for Listeria monocytogenes, to high hydrostatic pressure in liquid whole egg was studied at several pressures (300, 350, 400, and 450 MPa),temperatures (- 15, 2, and 20 degrees C), and times (5, 10, and 15 min). Listeria innocus was added to liquid whole egg at approximately 10(6) CFU/ml. Listeria innocua was not totally inactivated in any of the treatments. In general, reduction was better at 2 degrees than at room temperature, but the greatest inactivation was obtained at 450 MPa at 20 degrees C for 15 min (over 5 log of reduction), The results indicate that microbial inactivation was increased with prolonged exposure to pressure. D values for Listeria innocua were obtained at 400 MPa for two temperatures (2 and 20 degrees C), and different times (0 to 20 min). The microbial inactivation followed apparent first-order kinetics, exhibiting a decimal reduction time of 7.35 min at 2 degrees C and 8.23 min at 20 degrees C.
Unitat de Tecnologia dels Aliments, C.e.R.T.A., Facultat de Veterinária, Universitat Autónoma de Barcelona, Spain. IVPPK@cc.uab.es
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Ponce
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Pla
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Mor-Mur
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Gervilla
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Guamis
D000818:Animals; D015169:Colony Count, Microbial; D004531:Eggs / Q000382:microbiology*; D005519:Food Preservation / Q000379:methods*; D006874:Hydrostatic Pressure; D008087:Listeria / Q000254:growth & development; D011200:Poultry; D013696:Temperature; D013997:Time Factors