M L Capra1, A Quiberoni, J A Reinheimer. 1. Programa de Lactología Industrial, Facultad de Ingeniería Química, (Universidad Nacional del Litoral), Santiago del Estero, Santa Fe, Argentina.
Abstract
AIMS: The survival of two collection Lactobacillus casei and L. paracasei bacteriophages when subjected to thermal and chemical treatments was investigated. METHODS AND RESULTS: Thermal resistance was evaluated by heating phage suspensions at 63, 72 and 90 degrees C in three different media [Tris-magnesium gelatin (TMG) buffer: 10 mmol l(-1) Tris-Cl, 10 mmol l(-1) MgSO(4) and 0.1% w/v gelatin; Man Rogosa Sharpe (MRS) broth and reconstituted nonfat dry skim milk (RSM)]. A marked heat sensitivity was evident in both phages, as 15 min at 72 degrees C was enough to completely inactivate (6 log(10) reduction) them. No clear influence was demonstrated by the suspension media. The phages also showed similar resistance to biocides. Peracetic acid and sodium hypochlorite (800 ppm) were the most effective ones, destroying the phages within 5 min. Concentrations of 75 and 100% ethanol were not suitable to inactivate phage particles even after 45 min. Isopropanol did not show an effect on phage viability. CONCLUSIONS: The data obtained in this work are important to design more effective control procedures in order to inactivate phages in dairy plants and laboratories. SIGNIFICANCE AND IMPACT OF THE STUDY: This work will contribute to enhance the background knowledge about phages of probiotic bacteria.
AIMS: The survival of two collection Lactobacillus casei and L. paracasei bacteriophages when subjected to thermal and chemical treatments was investigated. METHODS AND RESULTS: Thermal resistance was evaluated by heating phage suspensions at 63, 72 and 90 degrees C in three different media [Tris-magnesium gelatin (TMG) buffer: 10 mmol l(-1) Tris-Cl, 10 mmol l(-1) MgSO(4) and 0.1% w/v gelatin; Man Rogosa Sharpe (MRS) broth and reconstituted nonfat dry skim milk (RSM)]. A marked heat sensitivity was evident in both phages, as 15 min at 72 degrees C was enough to completely inactivate (6 log(10) reduction) them. No clear influence was demonstrated by the suspension media. The phages also showed similar resistance to biocides. Peracetic acid and sodium hypochlorite (800 ppm) were the most effective ones, destroying the phages within 5 min. Concentrations of 75 and 100% ethanol were not suitable to inactivate phage particles even after 45 min. Isopropanol did not show an effect on phage viability. CONCLUSIONS: The data obtained in this work are important to design more effective control procedures in order to inactivate phages in dairy plants and laboratories. SIGNIFICANCE AND IMPACT OF THE STUDY: This work will contribute to enhance the background knowledge about phages of probiotic bacteria.
Authors: Mariángeles Briggiler Marcó; Antonio Carlos Negro; Orlando Mario Alfano; Andrea Del Luján Quiberoni Journal: Environ Sci Pollut Res Int Date: 2017-04-12 Impact factor: 4.223
Authors: Amira Shousha; Nattakarn Awaiwanont; Dmitrij Sofka; Frans J M Smulders; Peter Paulsen; Michael P Szostak; Tom Humphrey; Friederike Hilbert Journal: Appl Environ Microbiol Date: 2015-05-01 Impact factor: 4.792