Radiation sensitivity of poliovirus, a model for norovirus, inoculated in oyster (Crassostrea gigas) and culture broth under different conditions

Radiosensitivity increase in FCV-F9 virus using combined treatments with natural antimicrobials and γ-irradiation

AIMS

The objective was to evaluate the possible synergistic effect of cranberry juice (CJ) and commercial citrus extract (BS) against FCV-F9 viral titre in vitro in combination with γ-irradiation and to determinate the D₁₀ values and radiosensitivity increase.

METHODS AND RESULTS

Virus samples were treated with a formulation containing a mixture of BS or CJ. Results showed a D₁₀ of 0·05, 0·42% and 1·34 kGy for the virus treated with the BS, the CJ and the irradiation alone respectively. Concentrations needed to reduce 6 log TCID₅₀  ml^-1 of viral titre were BS-0·3%, CJ-2·52% and 8·04 kGy. Irradiation combined with BS-0·01% and CJ-0·1% against FCV-F9 virus showed D₁₀ values of 0·74 and 0·72 kGy, respectively, resulting in a viral radiosensitization of 1·28 and 1·50 for respective treatments.

CONCLUSION

The higher viral radiosensitization observed after combining γ-irradiation with BS-0·01% and CJ-0·1% indicates that CJ and BS could be used as antiviral agents alone or in combination with γ-irradiation to prevent NoV outbreaks.

SIGNIFICANCE AND IMPACT OF THE STUDY

Cranberry juice and BS could be used in hurdle approaches in combined treatment with γ-irradiation to assure food safety without a detrimental effect on nutritional value and maintain low processing cost.

Foodborne viruses: Detection, risk assessment, and control options in food processing

In a recent report by risk assessment experts on the identification of food safety priorities using the Delphi technique, foodborne viruses were recognized among the top rated food safety priorities and have become a greater concern to the food industry over the past few years. Food safety experts agreed that control measures for viruses throughout the food chain are required. However, much still needs to be understood with regard to the effectiveness of these controls and how to properly validate their performance, whether it is personal hygiene of food handlers or the effects of processing of at risk foods or the interpretation and action required on positive virus test result. This manuscript provides a description of foodborne viruses and their characteristics, their responses to stress and technologies developed for viral detection and control. In addition, the gaps in knowledge and understanding, and future perspectives on the application of viral detection and control strategies for the food industry, along with suggestions on how the food industry could implement effective control strategies for viruses in foods. The current state of the science on epidemiology, public health burden, risk assessment and management options for viruses in food processing environments will be highlighted in this review.

Susceptibility of murine norovirus and hepatitis A virus to electron beam irradiation in oysters and quantifying the reduction in potential infection risks

Consumption of raw oysters is an exposure route for human norovirus (NoV) and hepatitis A virus (HAV). Therefore, efficient postharvest oyster treatment technology is needed to reduce public health risks. This study evaluated the inactivation of HAV and the NoV research surrogate, murine norovirus-1 (MNV-1), in oysters (Crassostrea virginica) by electron beam (E-beam) irradiation. The reduction of potential infection risks was quantified for E-beam irradiation technology employed on raw oysters at various virus contamination levels. The E-beam dose required to reduce the MNV and HAV titer by 90% (D(10) value) in whole oysters was 4.05 (standard deviations [SD], ±0.63) and 4.83 (SD, ±0.08) kGy, respectively. Microbial risk assessment suggests that if a typical serving of 12 raw oysters was contaminated with 10(5) PFU, a 5-kGy treatment would achieve a 12% reduction (from 4.49 out of 10 persons to 3.95 out of 10 persons) in NoV infection and a 16% reduction (from 9.21 out of 10 persons to 7.76 out of 10 persons) in HAV infections. If the serving size contained only 10(2) PFU of viruses, a 5-kGy treatment would achieve a 26% reduction (2.74 out of 10 persons to 2.03 out of 10 persons) of NoV and 91% reduction (2.1 out of 10 persons to 1.93 out of 100 persons) of HAV infection risks. This study shows that although E-beam processing cannot completely eliminate the risk of viral illness, infection risks can be reduced.

Thermoluminescence analysis of irradiated oyster shells

This paper reports the thermoluminescence (TL) analysis performed on the oyster shells powder. TL response of (60)Co gamma-rays irradiated samples were studied in the range from 80 Gy to 8 kGy doses. TL signal of irradiated shell powder was higher as compared to the unirradiated control samples, which allowed to identify the irradiated oysters. Results show that the oyster shells have good TL properties and can be useful for the identification of irradiated seafood as well as for the evaluation of the treatment dose.