UV–C irradiation as a tool to eradicate algae in caves

Algal proliferation has commonly been reported to occur on monuments, such as crypts, churches, and caves, as soon as artificial lighting is used. In this work we study the effects of UV–C irradiation on algae collected in different caves in Dordogne (southwest of France). First, the effect of UV–C irradiation was tested on algal cell suspensions during increasing exposure times. After treatment, the photosynthetic capacity was assayed using a polarometric method, and algal cell viability was then estimated using a Trypan blue test after a rest period of 15 h. UV–C irradiation was then studied on algal cells cultivated on a solid support consisting of pieces of calcareous stone. Drops of concentrated algal cells were inoculated on stone and exposed to UV–C radiation for 3, 6, or 9 h. After this irradiation, half of the samples were submitted to a high white light intensity (1400 μmol m−2 s−1 of photosynthetically active radiation, PAR) for 6 h while the other half were incubated in the culture room. Subsequently, algal macroscopic parameters such as covering rate and colonized area were measured by macro photography. Both experiments led to the conclusion that UV–C irradiation has deleterious effects on photosynthetic parameters and growth of algal cells

Qualité des fromages fermiers lactiques : locaux et maitrise de l’affinage (LACTAFF)

Le programme LACTAFF (2012 – 2015) a eu pour objectif d’améliorer la maîtrise de l’affinage des fromages fermiers lactiques, technologie la plus couramment utilisée à la ferme, en fournissant des outils et des références aux producteurs et aux techniciens qui les accompagnent. Des enquêtes menées dans 49 fermes des 6 principales régions produisant ce type de fromage ont permis de caractériser la grande diversité des fromages fabriqués, des locaux, des équipements et des pratiques et d’établir des liens entre les grandes catégories de fromages et les pratiques, locaux et conditions d’ambiance. Par ailleurs, au laboratoire et en fromageries expérimentales, le rôle clé de l’hygrométrie a été quantifié en affinage, ainsi qu’au séchage où la vitesse d’air joue un rôle encore plus important. Les effets des paramètres d’ambiance sur la composition physico-chimique et les caractéristiques sensorielles des fromages ont été quantifiés pour un type de fromage donné.The « LACTAFF » program (2012-2015) aimed at improving the control of goat lactic farmhouse cheese ripening, a technology frequently used by farmers, by producing tools and references for producers and the technicians guiding them. Surveys conducted in 49 farms in the 6 main regions producing this kind of cheeses allowed to characterize the great diversity of cheeses, premises, equipment and practices, and to link cheese categories with practices, premises characteristics and air production conditions. In laboratory and experimental dairies, the key role of humidity was quantified during ripening and during drying, in which air speed is even more important. Atmospheric parameters effects on cheeses physicochemical composition and sensory characteristics were quantified for one type of cheeses. Specialist experience of cheese technology, premises design and climate control equipment and technician experience were capitalized at the same time. This project led to the writing of technical documents available online and a book about lactic farmhouse cheeses ripening