Towards Building a Food Knowledge Graph for Internet of Food.

Background: The deployment of various networks (e.g., Internet of Things (IoT) and mobile networks) and databases (e.g., nutrition tables and food compositional databases) in the food system generates massive information silos due to the well-known data harmonization problem. The food knowledge graph provides a unified and standardized conceptual terminology and their relationships in a structured form and thus can transform these information silos across the whole food system to a more reusable globally digitally connected Internet of Food, enabling every stage of the food system from farm-to-fork. Scope and approach: We review the evolution of food knowledge organization, from food classification, food ontology to food knowledge graphs. We then discuss the progress in food knowledge graphs from several representative applications. We finally discuss the main challenges and future directions. Key findings and conclusions: Our comprehensive summary of current research on food knowledge graphs shows that food knowledge graphs play an important role in food-oriented applications, including food search and Question Answering (QA), personalized dietary recommendation, food analysis and visualization, food traceability, and food machinery intelligent manufacturing. Future directions for food knowledge graphs cover several fields such as multimodal food knowledge graphs and food intelligence.