Application of permanganate to reduce microbial contamination and sugar loss in raw-sugar production in Louisiana, USA

Authors: Boone, Stephanie; IHLI, SAM - Carus Corporation; HARTSOUGH, DAN - Carus Corporation; HERNANDEZ, LOUIS - Carus Corporation; SANDERS, JOHN - Carus Corporation; Klasson, K Thomas; Lima, Isabel

Submitted to: International Sugar Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2020
Publication Date: 4/1/2020
Publication URL: https://handle.nal.usda.gov/10113/6937448
Citation: Boone, S., Ihli, S., Hartsough, D., Hernandez, L., Sanders, J., Klasson, K.T., Lima, I.M. 2020. Application of permanganate to reduce microbial contamination and sugar loss in raw-sugar production in Louisiana, USA. International Sugar Journal. 122(1456):254-260.

Interpretive Summary: During the 2016-2018 harvest seasons, some sugarcane factories in Louisiana applied permanganate to mill tandems and other factory locations. Sugar purity, sugar content, and microbial growth were evaluated, as well as manganese distribution in the raw sugar process. Sample collection included crusher juice, mixed juice, clarified juice, syrup and final molasses. In concurrent studies, samples were collected and brought back to the laboratory for studies under controlled conditions. Both laboratory and factory samples treated with permanganate indicated a reduction in microbial contamination by 94% in laboratory tests and microbial load in factory mixed juice was also reduced. Factory treated samples also showed increases in purity. All this was taken as strong indication of lower microbial load. There was a statistically significant difference between treated and untreated mixed juice purity. Juice purity loss (from crusher to mixed juice) were reduced from 1.55% to 0.80% during permanganate application, when long term factory data were evaluated. During permanganate application, the highest concentration of manganese was found in clarifier mud, indicating that permanganate is passively discarded from raw-sugar processing as insoluble manganese dioxide.

Technical Abstract: During the 2016-2018 harvest seasons, some sugarcane factories in Louisiana applied permanganate to mill tandems and other factory locations. Brix, purity, sugar content, microbial growth and mannitol were evaluated, as well as manganese distribution in the raw sugar process. Sample collection included crusher juice, mixed juice, clarified juice, syrup and final molasses. In concurrent studies, samples were collected and brought back to the laboratory for studies under controlled conditions. Both laboratory and factory samples treated with permanganate indicated a reduction in microbial contamination. Leuconostoc contamination was reduced by 94% in laboratory tests and microbial load in factory mixed juice was reduced from 2.2 OD600nm to 0.8-1.3 OD600nm. Factory treated samples also showed decreases in mannitol and increases in glucose:fructose ratio and purity. All this was taken as strong indication of lower microbial load. There was a statistically significant difference between treated and untreated mixed juice purity. Juice purity loss (from crusher to mixed juice) were reduced from 1.55% to 0.80% during permanganate application, when long term factory data were evaluated. During permanganate application, the highest concentration of manganese was found in clarifier mud, indicating that permanganate is passively discarded from raw-sugar processing as insoluble manganese dioxide.