Resistance of two temperate Lactobacillus paracasei bacteriophages to high pressure homogenization, thermal treatments and chemical biocides of industrial application

MERCANTI, D.; GUGLIELMOTTI, D.; PATRIGNANI, F.; REINHEIMER, J.; QUIBERONI, A.

FOOD MICROBIOLOGY

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: London; Año: 2012 vol. 29 p. 99 - 104

0740-0020

Temperate bacteriophages iLp84 and iLp1308, previously isolated from mitomycin C-induction of Lactobacillus paracasei strains 84 and CNRZ 1308, respectively, were tested for their resistance to several physical and chemical treatments applied in dairy industry. Long-term survival at 4°C, -20°C and -80°C, resistance to either thermal treatments of 63°C, 72°C and 90°C, high pressure homogenization (HPH, 100 MPa) or classic (ethanol, sodium hypochlorite and peracetic acid) and new commercial sanitizers, namely A (quaternary ammonium chloride), B (hydrogen peroxide, peracetic acid and peroctanoic acid), C (alkaline chloride foam), D (p-toluensulfonchloroamide, sodium salt) and E (ethoxylated nonylphenol and phosphoric acid), were determined. Phages were almost completely inactivated after eight months of storage at 25 °C, but viability was not affected at 4 C, -20 C or -80°C. Both phages tolerated well HPH treatments. Phage iLp1308 showed higher thermal resistance than iLp84, but neither resisted 90°C for 2 min. Best chemical inactivation was accomplished using peracetic acid or biocides A, C and E, whereas biocides B and D were completely ineffective. These results help to improve selection of chemical agents and physical treatments to effectively fight against phage infections in dairy plants.