Thermal, chemical and photocatalytic inactivation of Lactobacillus plantarum bacteriophages

M. BRIGGILER MARCÓ,; G. DE ANTONI; J. REINHEIMER; A. QUIBERONI

JOURNAL OF FOOD PROTECTION

International Association for Food Protection

Lugar: Iowa; Año: 2009 vol. 72 p. 1012 - 1019

0362-028X

The effect of several biocides, thermal treatments and photocatalysis on the viability of four Lactobacillus plantarum phages was investigated. Times to achieve 99% inactivation of phages at 63ºC, 72ºC and 90ºC in four suspension media (MRS broth, reconstituted skim milk, a commercial EM-glucose medium and TMG buffer) were studied. The four phages studied were highly resistant to 63ºC (T99>45); however, counts <10 PFU/ml were achieved by heating at 90ºC during 5 min. A higher thermal resistance at 72 ºC was observed when RSM and EM-glucose medium were assayed. As regards the effects of biocides on phages, peracetic acid (0.15% vol/vol) was found to be an effective biocide for the complete inactivation of all phages studied within 5 min of exposure. Sodium hypochlorite -800 ppm- inactivated the phages completely within 30 min.  Ethanol at a concentration of 100% was not suitable to destroy phage particles even after 45 min. Isopropanol did not show any effect on phage viability. Phage counts <50 PFU/ml were obtained within 180 min of photocatalytic treatment. The results obtained in this work are important to establish adequate treatments to inactivate phages in industrial plants and laboratory environments.