Response to the Questions Posed by the Food Safety and Inspection Service, the Centers for Disease Control and Prevention, the National Marine Fisheries Service, and the Defense Health Agency, Veterinary Services Activity Regarding Control Strategies for Reducing Foodborne Norovirus Infections

The National Advisory Committee on Microbiological Criteria for Foods (NACMCF or Committee) was asked to assess the incidence and public health burden of human norovirus (HuNoV) infection and the importance of food as a source of attribution to foodborne HuNoV infections. The Committee was also asked to provide advice on intervention, control, and mitigation strategies to reduce, inactivate, and/ or eliminate HuNoV contamination in foods, on surfaces, and in the environment; to evaluate the current methods for detection of HuNoV in food and environmental samples; and to determine what data are still needed to conduct a quantitative risk assessment. Individual working groups were developed to address the charge questions. Each chapter outlines the Committee response to the charge questions as well as gaps and recommendations for additional data and/or research needs. Summary recommendations of the Committee are identified at the end of the document. In the background statement relative to the charges it was noted that HuNoVs have been identified as the leading cause of both acute gastroenteritis and foodborne infection in the United States, as well as a leading cause of epidemic and sporadic acute gastroenteritis (AGE) worldwide. However, the fraction of illness attributable to food has been estimated using outbreak data, which indicates a greater tendency to investigate and report outbreaks as foodborne rather than person-to-person. The Committee concluded that there are existing gaps in the data related to transmission and secondary transmission of the illness. After examining the current scientific and technical literature, the Committee determined that, while there are many publications related to noroviruses, and several research groups are currently investigating norovirus, the current methods for detection of HuNoV have significant limitations. The lack of sensitive and specific methods to rapidly detect infectious virus in clinical and food samples was identified as a major barrier to advancing the understanding of HuNoV foodborne ecology, epidemiology, transmission, control, and detection. The Committee agreed with currently existing guidance that address norovirus prevention, control, and outbreak management by excluding ill food workers, limiting bare-hand contact with ready-to-eat foods, practicing proper hand hygiene, and cleaning and sanitizing surfaces on a frequent basis. However, a significant amount of research related to additional interventions, mitigation, and control strategies has been conducted using surrogate organisms. A lack of comparative data between surrogates and HuNoV raises questions on the appropriateness of surrogates as models for HuNoV behavior. Therefore, the Committee was unable to assess the most appropriate control strategy or intervention for use at this time and recommended that surrogates need to be identified and confirmed as adequate representatives of HuNoVs for use in research, validation, and verification.