Detection and inactivation of parasites on berries: development and implementation of food safety tools for the industry.

During the last decades, Norwegian consumption of fresh fruit and vegetables has been increasing steadily. At the same time, new food trends have led to different uses of these products; previous generations would make jam, but now it is more common to put berries in smoothies, without any heat treatment. In the same period, import of fresh produce to Norway has increased dramatically, and we are now able to enjoy a large variety of fresh berries and fruit throughout the whole year. Although there are many health benefits associated with these dietary changes, there are also challenges related to food safety. Norway still has a very low prevalence of serious infectious diseases, but this situation could change, and new pathogens may be introduced by human and animal travel, or by contaminated food. Infectious diseases that can be imported and transmitted via food include bacteria, viruses, fungi, and parasites. Of these, parasites have been the focus of greater attention in recent years, partly because they have caused several foodborne outbreaks. Parasites can be difficult to detect, and many of them have tough transmission stages, which makes inactivation difficult without destroying the food product. Some parasites, e.g. Echinococcus multilocularis, can cause serious, potentially life-threatening, disease in humans. A lack of good methods for detection of these parasites has made it difficult to perform studies on the prevalence, and thus the impact, of foodborne parasites on human health. The Norwegian University of Life Sciences addressed these challenges through the PARA-BERRY project, in which, together with partners, we developed new methods for parasite detection in berries. Through PARA-BERRY we used these methods to analyze imported and locally grown berries for the presence of parasites. Information gained through the project is intended to assist the industry in taking appropriate action to reduce the risk of human infection. The last part of the PARA-BERRY årpkect was to complete the survey on of imported and locally produced berries in Norway for parasite contamination. We detected parasites on 2.9% (Toxoplasma), 6.6% (Cyclospora), and 8.3% (Cryptosporidium) of the berry samples. E. multilocularis was not detected. In parallel, the PARA-BERRY Phd candidate developed a new molecular (RT-qPCR) protocol for assessing the viability of parasites that can be transmitted with berries and other fresh produce. We also tested different consumer-level washing methods for removal of parasites from contaminated berries. Cost-benefit analyses for assessing different measures that can be used to reduce the chance of parasite transmission to humans will be completed after the closure of the project.

Outcomes: -method for detection of important parasites on berries; already implemented in other research groups and relevant for others. -viability assay based on upregulation of genes following oxidative stress. -data on parasite contamination of berries in Norway; of value for stakeholders. -increased collaboration with researchers & stakeholders; e.g EFSA-funded project on molecular detection methods to improve risk assessment capacity for foodborne protozoan parasites; in US-based consortium applying for federal funding for Cyclospora Collaborative for Outreach, Research, and Education (CycloCORE). Potential outcomes (work incomplete): -effects of sanitizers and inactivation methods on parasite viability -analysis of economic effects of foodborne parasites on fresh produce. Potential impacts include: -improved awareness (consumers & industry) on foodborne parasites -inspire industry to be pro-active e.g. information to consumers on washing berries.

Raw fresh produce is an essential part of a balanced diet, but a healthy diet should also be a safe diet, and fresh produce can be a vehicle for transmission of pathogens. Parasites are the pathogen group for which foodborne transmission has the greatest lack of information. PARA-BERRY will develop tools for detection of parasites as contaminants of berries (an increasingly consumed fresh product group, usually consumed raw) and generate data on their prevalence to be able to address potential contamination. Many parasites have the potential for transmission via fresh produce, and PARA-BERRY will focus on three that are of particular relevance to Norway in terms of research needs: i) Echinococcus multilocularis, ii) Toxoplasma gondii, and iii) Cyclospora cayetanensis. A major challenge related to parasites that may be transmitted by contaminated produce is their tough transmission stages that enable their prolonged survival. Although heating and desiccation inactivate the infective stages, such measures are inappropriate for use on berries to be eaten raw. PARA-BERRY will therefore explore methods for inactivation and removal of the transmission stages from contaminated berries. In order to address this question, PARA-BERRY will also develop and optimize methods for assessment of whether parasite transmission stages on berries are viable. New understandings of potential threats generate benefits for consumers, but may come at an economic cost that should not be neglected. Cost-benefit analyses will be used to determine how the methods developed can be most usefully implemented in the fresh-produce chain in order to improve the Pareto efficiency. It should not be forgotten that consumers tend to trust industries that are serious regarding reducing the risks associated with their products. PARA-BERRY is a knowledge-generating research project, with a timely and definitive industry benefit. Industry interests will be kept in focus through the reference group.