Mold Identification & Types Flashcards

What is the minimum water activity (aw) level at which most common indoor molds can begin to grow?

Answer: 0.70

Most common indoor molds require a minimum water activity of approximately 0.70 to initiate growth, though optimal growth occurs at higher levels.

Which mold genus is most likely to be found growing on refrigerated food and can produce ochratoxin?

Answer: Penicillium

Penicillium species commonly colonize refrigerated foods and can produce mycotoxins including ochratoxin A.

Ulocladium is morphologically similar to which other common mold genus, making them sometimes difficult to distinguish?

Answer: Alternaria

Ulocladium and Alternaria share similar dark, multi-celled conidia morphology, requiring careful microscopic examination to differentiate.

What type of mold growth pattern is described when hyphae penetrate deeply into a substrate rather than growing only on the surface?

Answer: Invasive growth

Invasive growth refers to hyphal penetration into substrate material, which can cause structural damage and makes remediation more difficult.

Which mold genus is bright green and commonly used as a biological control agent against other fungi?

Answer: Trichoderma

Trichoderma species are bright green molds widely used in agriculture as biocontrol agents because they parasitize other fungi.

In a bulk sample from water-damaged wood, Serpula lacrymans would indicate which specific type of decay?

Answer: Dry rot (brown cubical cracking decay)

Serpula lacrymans is the classic dry rot fungus that causes brown cubical cracking decay in structural timber, weakening it severely.

Which of the following best describes the term 'dematiaceous fungi' in the context of mold identification?

Answer: Darkly pigmented (melanized) molds such as Cladosporium and Alternaria

Dematiaceous fungi are darkly pigmented due to melanin in their cell walls; examples include Cladosporium, Alternaria, and Stachybotrys.