Effect of Calcium Propionate and Sodium Diacetate on Fungi in Stillage

Sodium diacetate was not effective for inhibiting fungal growth at 10 and 20 ppm in stillage produced at a “power-hol” facility and a distillery. Calcium propionate at a concentration of 20 ppm was effective in inhibiting microbial growth for up to 9 days in Jack Daniels stillage. For the Muscle Shoals stillage, calcium propionate at a concentration of 10 ppm was effective in inhibiting fungal growth for up to 14 days Stillage produced at Muscle Shoals had a slightly higher initial pH but a lower yeast content which is thought to have contributed to the longer shelf-life. Stillage produced at Jack Daniel had a lower solids content and a lower pH but supported more fungal growth and spoiled faster.