Industrial storage of green robusta coffee under tropical conditions and its impact on raw material quality and ochratoxin a content

Green Robusta coffee was stored in silos for 8 months under industrial conditions in Thailand, and subjected to air-conditioning, aeration, and nonaeration, and compared to bag storage under ambient conditions. Air-conditioning clearly reduced the relative humidity (RH) of the silo atmosphere and the moisture content (MC) and the water activity (a(w)) of green coffee. Overall storage behavior was better for coffee in the aerated silo (RH 68%; MC = 13.0%; a(w) = 0.69) than for coffee stored in bags (RH = 81%; MC = 13.5%; a(w) = 0.72). Aeration provided an efficient means to reduce MC and a, during the rainy period. Glucose content was linked positively with the increase of a woody/rubbery note in coffee cup quality and increased by similar to 50% between months 3 and 6 when green coffee MC and a(w) increased the most. Glucose is a potential green coffee quality marker. Under the tested storage conditions, neither the growth and presence of ochratoxin A (OTA)-producing fungi nor consistent OTA production was found. OTA contamination appeared to have occurred before storage.