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tation of the outside world, including its chemical (taste and olfaction) and physical (mechanical, sound, vision and temperature) features. In this review we examine recent advances in our understanding of the biology of taste, focusing on receptors, cells and the logic of taste coding at the periphery. Taste is in charge of evaluating the nutritious content of food and preventing the ingestion of toxic substances. Sweet taste permits the identification of energy-rich nutrients, umami allows the recognition of amino acids, salt taste ensures the proper dietary electrolyte balance, and sour and bitter warn against the intake of potentially noxious and/or poisonous chemicals. In humans, taste has the additional value of contributing to the overall pleasure and enjoyment of a meal. Surprisingly, although we can taste a vast array of chemical entities, it is now generally accepted that, qualitatively, they evoke few distinct taste sensations: sweet, bitter, sour, salty and savoury (or umami). Although this repertoire may seem modest, it has satisfactorily accommodated the evolutionary need for an effective and reliable platform to help recognize and distinguish key dietary components. The receptors and cells for mammalian taste