Thermal, chemical and photocatalytic inactivation of Lactobacillus plantarum bacteriophages

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

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 (T99) of phages at 63, 72, and 90°C were evaluated in four  suspension media: deMan Rogosa Sharpe broth, reconstituted skim milk, a commercial EM-glucose medium, and Tris magnesium  gelatin buffer. The four phages studied were highly resistant to 63°C (T99 > 45 min); however, counts < 10 PFU/ml  were achieved by heating at 90°C for 5 min. Higher thermal resistance at 72°C was observed when reconstituted skim milk  and EM-glucose medium were assayed. Peracetic acid (0.15%, vol/vol) was 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 (100%) did not destroy phage particles even after 45 min. Isopropanol did not have 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 for establishing adequate methods for inactivating phages in industrial plants and laboratory environments.