Life strategies of wall-disfiguring moulds in relation to temperature fluctuations on the wall of a maltings kiln

Abstract

In a modern concrete-built maltings tower during 70° kilning cycles in winter the temperature on the inner surface of the kiln wall remained below 40° for almost the whole cycle time. In summer the temperature of the wall remained below that of the kiln air for most of the hot period but was above 40° for approximately half the cycle time. On malt extract agar, cultures of the three species isolated from the kiln wall, Fusarium chlamydosporum, Fusarium oxysporum and Phoma glomerata, had optimum temperatures for radial growth similar to those of a range of non-kiln wall moulds but grew at slightly higher maximum temperatures (35–40°). Mature colony regions of the kiln species survived exposure to higher temperatures for longer periods than did younger colony regions of these species or all regions of non-kiln species. All three kiln species formed chlamydospores in culture and chlamydospores were present on paint samples from the kiln wall two years after repainting.