Challenges in specialty coffee processes and quality assurance

Coffee is an important crop that assures a sustainable economy to tropical regions farmers. Coffee beans are produced from coffee berries by removing the outer fruit layers through dry or wet processes. Quality of coffee depends on optimized protocols of cultivation, ripe berries collection, fermentation or other processes to remove the mucilage, and, finally, moisture reduction. A big concern for coffee production is currently represented by climate change, that threatens the survival of Coffea arabica cultivation worldwide and imposes different strategies to react to this issue. Storage and shipment represent two steps where bean quality needs to be preserved by preventing fungal contamination that may impact the final product. In this review we describe the challenges afforded by the coffee industry to guarantee quality from production to roasting and brewing. An overview on novel technologies, such as the application of starter strains and the exploitation of industrial enzymes in accelerating the process of flavour development in coffee beans, is given. Moreover, the results of studies on microbial populations and the differences found in fungi, yeasts and bacteria composition among the investigations, are summarized. In particular, this review describes new attempts to contain the development of mycotoxigenic fungi, through the application of antagonistic microorganisms such as S. cerevisiae. The new wave of specialty coffees, i.e. those with a cupping score higher than 85/100, is also presented. It is shown how, through careful coffee production methods and controlled fermentation processes producers may increase their income by producing specialty coffees with high standards of quality and high added value for the sector area of coffee experience.