American Society of Microbiology – Effect of Temperature and Relative Humidity on the Survival of Foodborne Viruses during Food Storage
Millions of people suffer from foodborne diseases throughout the world every year, and the importance of food safety has grown worldwide in recent years. The aim of this study was to investigate the survival of hepatitis A virus (HAV) and viral surrogates of human norovirus (HuNoV) (bacteriophage MS2 and murine norovirus [MNV]) in food over time. HAV, MNV, and MS2 were inoculated onto either the digestive gland of oysters or the surface of fresh peppers, and their survival on these food matrices was measured under various temperature (4°C, 15°C, 25°C, and 40°C) and relative humidity (RH) (50% and 70%) conditions. Inoculated viruses were recovered from food samples and quantified by a plaque assay at predetermined time points over 2 weeks (0, 1, 3, 7, 10, and 14 days). Virus survival was influenced primarily by temperature. On peppers at 40°C and at 50% RH, >4- and 6-log reductions of MNV and HAV, respectively, occurred within 1 day. All three viruses survived better on oysters. In addition, HAV survived better at 70% RH than at 50% RH. The survival data for HAV, MS2, and MNV were fit to three different mathematical models (linear, Weibull, and biphasic models). Among them, the biphasic model was optimum in terms of goodness of fit. The results of this study suggest that major foodborne viruses such as HAV and HuNoV can survive over prolonged periods of time with a limited reduction in numbers. Because a persistence of foodborne virus on contaminated foods was observed, precautionary preventive measures should be performed.
Ingenta Connect – Consumer Education Needed on Norovirus Prevention and Control: Findings from a Nationally Representative Survey of U.S. Adults
Noroviruses (NoVs) are the leading cause of foodborne disease in the United States; however, little is known about consumers’ knowledge of NoV infection and their understanding of how to prevent and control associated illness. A nationally representative Web-enabled panel survey of U.S. adults (n = 1,051) was conducted to collect information on consumers’ awareness and knowledge of NoVs. Respondents who had heard of NoVs were asked 22 true-and-false questions on the transmission, prevention, and control of NoVs. Forty-seven percent of respondents reported awareness of NoVs, and 85% of respondents had heard of the terms “cruise ship virus,” “the stomach bug,” or “the stomach flu,” which are commonly used to describe NoVs. Of those respondents who had previously heard of NoV or other terms used by consumers to describe NoV (n = 948), 36% correctly answered 11 or more of the 22 true-and-false questions, suggesting that consumers have limited knowledge on how to prevent and control NoV infection. Most consumers do not understand that the primary mode of transmission for NoV infection is fecal to oral, and many have the misperception that meat and poultry are sources of NoV infection. There is the need to educate consumers about how to prevent and control NoV infection. Although there is a proliferation of food safety education materials available, most focus on foodborne bacteria rather than viruses. The survey results will be used to revise existing consumer food safety educational materials to include information on NoV prevention and control.
American Society of Microbiology – Inactivation of a Foodborne Norovirus Outbreak Strain with Nonthermal Atmospheric Pressure Plasma
Human norovirus (NoV) is the most frequent cause of epidemic nonbacterial acute gastroenteritis worldwide. We investigated the impact of nonthermal or cold atmospheric pressure plasma (CAPP) on the inactivation of a clinical human outbreak NoV, GII.4. Three different dilutions of a NoV-positive stool sample were prepared and subsequently treated with CAPP for various lengths of time, up to 15 min. NoV viral loads were quantified by quantitative real-time reverse transcription PCR (RT-qPCR). Increased CAPP treatment time led to increased NoV reduction; samples treated for the longest time had the lowest viral load. From the initial starting quantity of 2.36 × 104 genomic equivalents/ml, sample exposure to CAPP reduced this value by 1.23 log10 and 1.69 log10 genomic equivalents/ml after 10 and 15 min, respectively (P < 0.01). CAPP treatment of surfaces carrying a lower viral load reduced NoV by at least 1 log10 after CAPP exposure for 2 min (P < 0.05) and 1 min (P < 0.05), respectively. Our results suggest that NoV can be inactivated by CAPP treatment. The lack of cell culture assays prevents our ability to estimate infectivity. It is possible that some detectable, intact virus particles were rendered noninfectious. We conclude that CAPP treatment of surfaces may be a useful strategy to reduce the risk of NoV transmission in crowded environments.
As the fears associated with Hepatitis A risks from eating imported frozen berries continue, calls are mounting for measures to prevent risks of future outbreaks.
Eating only Australian grown fruit and vegetables, better country-of-origin labelling and stricter biosecurity controls are among measures being called for.
However these are not issues that have emerged overnight.
For more than 20 years the Country Women’s Association of NSW has lobbied against the importation of foods and to improve biosecurity laws so that Australia’s fruit and vegetable industries are protected and the possibility of food contamination is reduced.
FoodWorld 