Evaluation of current and future intervention measures for reducing norovirus in the food industry.

Virus detection:

• Cell culture
• QPCR

Intervention measures:

• Washing with chemical sanitizers e.g. NaOCl, O3, Peracitic acid
• Gamma radiation/Electron beam radiation
• High Pressure Processing (HPP)

Noroviruses are the main cause of foodborne viral gastroenteritis worldwide. Nevertheless, food hygiene guidelines such as HACCP are only directed at fungal or bacterial pathogens. Thus, current intervention measures used in the food industry are not yet evaluated for their efficacy in viral inactivation. The raspberry and lettuce production chain will be studied in this work, because both produces have caused norovirus outbreaks in the past. Besides chlorine washing, which is mainly applied as an intervention measure in the fresh produce industry, also other non-thermal inactivation measures such as irradiation, HPP, or the use of ozone will be studied for their efficacy in norovirus inactivation. A final verification of the disinfectant efficacy will be done by undertaking experiments on pilot plant scale and in field experiments. In addition to the inactivation potential, critical parameters influencing the inactivation efficacy such as pH and temperature, and the impact of the processes on produce quality will be analyzed. The gathered quantitative data on norovirus survival and reduction will feed back into quantitative viral risk assessment which will ultimately lead to HACCP based handbooks.

The PhD thesis is part of the EU project: "Integrated monitoring and control of foodborne viruses in European food supply chains" (VITAL)