Mitigation strategies to reduce the microbial risks and improve the quality and safety of frozen and ready-to-eat strawberries

The concern about the microbiological safety of fresh, minimally processed and ready-to-eat fruits and vegetables has increased in recent years due to the emergence of several outbreaks of foodborne pathogens linked to their consumption. In 2014, EFSA published a scientific opinion about the risk of Salmonella and Norovirus in berries in which they included strawberries. Among the final recommendations, they indicated the need for targeted surveys on the occurrence of Norovirus in different types of berries both at primary production, after minimal processing (including freezing) and at the point of sale. Moreover, they indicated the need to develop infectivity assays for Norovirus because of the current detection techniques by RT-PCR do not allow to distinguish the infective particles and determine whether they can internalize within berries. Finally, they remarked the need for more research on decontamination treatments effective against all relevant microbiological hazards.
The objectives of this project are: (i) to identify microbiological risks of fresh and frozen strawberries, including norovirus, (ii) to determine the possible internalization of pathogenic bacteria to the fruit through irrigation water, (iii) to study their survival in strawberries including the interaction with the main postharvest fungal pathogens, developing predictive models of growth and survival and to determine the ability of biofilm formation and (iv) to establish risk mitigation systems for safe and quality products. The alternative systems to the use of chlorine will include: alternative chemicals such as peroxyacetic acid, ozone, UV-water assisted, ultrasound and a dry treatment with iodized oxygen technology. The effectiveness of these methods will be evaluated from both microbiological and quality sides, considering physicochemical, nutritional (bioactive compounds and antioxidant properties) and sensorial aspects, including the volatile profile. Finally, a compressive model of quality and food safety will be developed in from the processing and distribution chain to the end consumer.