This is a cut and paste from an article I read It may explain the problem.
}Alcaligenes faecalis, the bacteria responsible for the white slime, can thrive in conditions where volatile organic compounds, or VOCs, and phthalates are present in high levels. Possible factors that increase VOCs can be air deodorizers, freshening systems, commercial carpet cleaning services, smoke and the use of the sterilizing instruments such as chemi-claves and other alcohol-based cleaners.