In Vivo Evaluation of the Potential of Thyme and Lemon Hydrolates as Processing Aids to Reduce Norovirus Concentration during Oyster Depuration

• Published in: Foods
• Main Authors: Roberta Battistini, Chiara Masotti, Daniela Manila Bianchi, Lucia Decastelli, Aitor Garcia-Vozmediano, Cristiana Maurella, Marie-Laure Fauconnier, Antonello Paparella, Laura Serracca
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2023
• Subjects: Crassostrea gigas; post-harvest processing; depuration; natural compounds; norovirus; Chemical technology; TP1-1185; Pacific
• Online Access: https://doi.org/10.3390/foods12213976; https://doaj.org/article/a82b6a2b36b04689becec27813016b40

In this study, we evaluated the use of hydrolates, co-products of essential oil distillation, as processing aids to improve the depuration process of Pacific oysters ( Crassostrea gigas ) as a post-harvest method aimed at reducing the norovirus (NoV) viral load. Live oysters were kept in water to which hydrolates of Thymus serpyllum and Citrus limon at 1% were added for 24 h. The concentration of NoV was quantified using the ISO 15216-1 quantitative real-time RT-PCR method in the oyster digestive tissue both before and after the treatment. The results showed a significant reduction of 0.2 log in the NoV GII concentration after 24 h of treatment with 1% C. limon hydrolate. Conversely, treatment with T. serpyllum did not appear to reduce the concentration of NoV compared to the control. Additionally, a sensory analysis was conducted through a blind survey comparing untreated and treated oysters. No changes in the sensory and physical characteristics of the oysters were observed, except for a decrease in the marine flavour intensity, which was positively perceived by consumers. These results indicate that the addition of hydrolates of C. limon at 1% during depuration might represent a promising processing aid for enhancing both the safety and acceptability of live oysters.