Effects of pH and temperature on the survival of coliphages MS2 and Q?

Abstract

The RNA F-specific coliphages, MS2 and Qbeta, have been used as virus indicators in water and wastewater studies. It is therefore useful to have a good understanding concerning the effects of environmental factors on their survival in order to choose an appropriate candidate for assessing microbial safety in relation to water quality management. The effects of pH and temperature on the survival of these two coliphages were investigated. MS2 survived better in acidic conditions than in an alkaline environment. In contrast, Qbeta had a better survival rate in alkaline conditions than in an acidic environment. The inactivation rates of both coliphages were lowest within the pH range 6-8 and the temperature range 5-35 degrees C. The inactivation rates of both coliphages increased when the pH was decreased to below 6 or increased to above 8. The inactivation rates of both coliphages increased with increasing temperature. Qbeta behaved peculiarly in extreme pH buffers, i.e. it was inactivated very rapidly initially when subjected to an extreme pH environment, although the inactivation rate subsequently decreased. In general, MS2 was a better indicator than Qbeta. However, within the pH range 6-9 and at temperatures not above 25 degrees C, either MS2 or Qbeta could be used as a viral indicator.

Male-Specific Coliphages as Indicators of Thermal Inactivation of Pathogens in Biosolids

“…Median reductions of group III (Qß-like) F ϩ RNA coliphage isolates were Ͼ2-log 10 greater than reductions of group I (MS2-like) isolates after 60 min of exposure to 53°C in TSB. These results are consistent with earlier work indicating that group I F ϩ RNA coliphages are more resistant to thermal inactivation than other groups of F ϩ RNA coliphages (9,24).…”

Use of coliphages to evaluate water treatment processes and determine faecal contamination origin of source waters

“…After sedimentation, the somatic coliphage counts were observed to have negative correlations with the physicochemical parameters (NTU, pH and temperature) from Temba and Wallmansthal, while, after filtration, positive correlations were observed from both Temba and Klipdrift (Table 4). Although, in some instances, the analysed physicochemical parameters in this study played a role in the removal of FRNA coliphages from the water, this group of viral indicators has been reported to be more resistant to environmental conditions (Grabow 2001;Feng et al 2003). This could clearly explain the 50 % reoccurrence of the FRNA coliphages in filtered water from the Wallmansthal Waterworks (Table 4).…”

“…Maintaining a temperature of B25 o C in accordance with the recommended standards (SANS: 241, 2006) is essential not only for the efficacy of the physicochemical reactions and preventing the toxicity of metals that most could possibly be found in the water (USEPA 1999(USEPA , 2001Momba et al 2006a), but also for promoting the inactivation of viruses in water (Grabow 2001;Cole et al 2003;Duran et al 2002). Collectively, virus removal and inactivation may be effectively achieved by increased temperatures and extremes of pH (Sinton et al 1999;Feng et al 2003).…”

“…This could clearly explain the 50 % reoccurrence of the FRNA coliphages in filtered water from the Wallmansthal Waterworks (Table 4). According to Feng et al (2003), the inactivation of FRNA coliphages has been reported to increase when the pH decreased to below 6 or increased above 8 and with the increment of temperature (Feng et al 2003). The effectiveness of coagulation, flocculation, sedimentation and filtration processes to remove viruses in water has been indicated to range roughly from 1 to 3 log (WHO 2004b).…”

Survival of Murine Norovirus, Tulane Virus, and Hepatitis A Virus on Alfalfa Seeds and Sprouts during Storage and Germination

“…In most cases, viruses tend to survive better at lower temperatures (25,35,42,43), and the temperature fluctuations could result in virus inactivation. In addition, alfalfa sprouts provided a neutral pH (44), and pH ranging from 6 to 8 has been shown to be preferable for virus survival, with decreased rates of inactivation (25,42,43,45). HBSS contains salts and provides a stable pH at ϳ7.25, which is within that range.…”