Thermal, chemical and photocatalytic inactivation of Lactobacillus plantarum bacteriophages

M. BRIGGILER MARCO; GRACIELA DE ANTONI; JORGE REINHEIMER; ANDREA QUIBERONI

JOURNAL OF FOOD PROTECTION

International Association for Food Protection

Año: 2009

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 90C 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 63C (T99  45 min); however, counts of 10 PFU/ ml were achieved by heating at 90C for 5 min. Higher thermal resistance at 72C 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 of 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 environmentsLactobacillus plantarum phages was investigated. Times to achieve 99% inactivation (T99) of phages at 63, 72, and 90C 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 63C (T99  45 min); however, counts of 10 PFU/ ml were achieved by heating at 90C for 5 min. Higher thermal resistance at 72C 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 of 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