Coordinated through the Ontario Maple Syrup Producers Association, 68 maple syrup producers sent samples proportional to the volume of production in each of the 11 maple-syrup producing districts in Ontario which span an area of ~ 250,000 km2. The samples from each producer comprised 6 250 ml containers of syrup (48 medium grade, 9 amber, 8 light and 3 ungraded). Samples were blind-coded for producer location with information on factors thought to predispose samples to mold contamination (e.g., cold packing, container type, reverse osmosis, wood versus oil heat, preheating containers). The samples were received at Carleton University over a three week period from the annual production in the spring of 2014 shipped via Canada Post by the producers. Samples were generally received within two days and were stored at room temperature in their original boxes until processed.