[7] Classification and identification of the genus Penicillium were solely based on morphological traits before DNA sequencing was discovered.

[8] Key characteristics that are commonly involved in the grouping of P. spinulosm include vesiculate, rapid growth, spherical rough conidia and long conidiophores that projected from tangled mass of aerial hyphae.

[3][4] In 1949, Raper & Thom classified P. spinulosum as a member of the Penicillium section Monovertcillata due to its simple conidiospores branching pattern.

[10][4] Penicillium spinulosum has thin-walled conidia with smooth or finely roughened texture terminating in a vesicle,[5] the stipes of conidiospores generally range from 100 to 300 μm long, occasionally the length can be shorter than that.

[4] However, modern phylogenetic studies of the genus Penicillium have revealed that these morphological patterns can arise independently, and thus do not reliably predict evolutionary relationships.

[3] Penicillium spinulosum is psychrophilic, meaning that it is able to grow and reproduce at low temperature,[5] and xerophile as it can germinate in decreased water activity environment (down to 0.8 Aw) by producing compatible solutes using enzyme systems.

[14] Colonies growth and germination of Penicillium spinulosum were extremely sensitive to several different disinfectants and preservatives, among them, potassium sorbate and Suma Bac imposed the strongest inhibition effect.

[11] When grow in a chemically defined glucose or sucrose medium, can produce large amount of fat that is non-toxic to rats.

[5] P. spinulosum has also been isolated from dextrin paste, distilled water containers, cotton yarn, walnut kernels, chrome tanned leather, vinyl wall covering, paracetamol tablet, diesel fuel and emulsion paint treated with chromate.