Mesophilic · Extended-panel species

Penicillium citreonigrum

Stored-grain Penicillium offered on extended panels for taxonomic completeness. Citreoviridin producer; limited modern indoor relevance.

Extended panelMesophilic · Aw ≥ 0.80

Moisture niche · where this species can grow

XerophilicAw < 0.80
MesophilicAw 0.80–0.89
HydrophilicAw ≥ 0.90
Min Aw 0.80
← Drier conditions toleratedRequires liquid water →
Minimum Aw
0.80
EPA reference (GM)
< 0.4 SE/mgMeklin AHHS threshold
Mycotoxin profile
1+ documented
Ecological role
Secondary colonizer

The < 0.4 SE/mg reference value is Meklin 2004's AHHS exclusion threshold: the paper retained species whose geometric mean was at least 2 spores per 5 mg dust (≈ 0.4 spores/mg) and eliminated the rest. This species was measured across the 1,096-home AHHS sample and characterized below that threshold, used here as a conservative ceiling on its true GM, not a percentile band. A detected value of X SE/mg implies an elevation factor of at least X ÷ 0.4 over the EPA reference, a lower bound, since the true GM is below 0.4. See the 82-species story for the math.

Note on cardinal Aw: ~0.80–0.83 (inferred from related Penicillia; species-specific cardinal values sparse).

About Penicillium citreonigrum

Penicillium citreonigrum (synonym P. citreoviride) is included on extended Penicillium panels primarily for taxonomic completeness within the genus. Its principal toxicological metabolite is citreoviridin. Modern indoor relevance is limited; the species is primarily a stored-grain organism rather than a building colonizer.

Taxonomy

Penicillium section Citrina (Houbraken & Samson 2011; section is characterized by citrinin and citreoviridin production)

Ecology and habitat

P. citreonigrum is primarily a stored-grain organism. It is uncommon in modern indoor isolations and is encountered most often in agricultural-adjacent storage contexts rather than typical residential buildings.

Indoor relevance

P. citreonigrum's indoor relevance is limited. Detection on a residential ERMI extended panel would be unusual; in agricultural-adjacent buildings with grain storage it is more plausible. Its inclusion on extended panels is principally for taxonomic completeness within the genus.

Cardinal physiology

Cardinal Aw values for P. citreonigrum are not as well-characterized as for the more commercially significant Penicillia. The species is broadly similar to other Penicillia in moisture and temperature tolerance, minimum Aw ~0.80–0.83, growth across 5–37 °C. This estimate should be treated as inferred from related species rather than primary-literature-derived.

Secondary metabolites

The principal toxicological metabolite is citreoviridin, a cardiotoxin / neurotoxin. No dedicated mycotoxin page exists for citreoviridin on this site; the molecule's modern indoor-exposure relevance is sufficiently narrow that it is mentioned here for completeness only.

Compounds documented as produced by Penicillium citreonigrum (presence and quantity vary by chemotype, strain, and substrate):

Citreoviridin (cardiotoxin / neurotoxin; mitochondrial ATPase inhibitor)

DNA-based detection of a mycotoxin-producing species in household dust does not directly establish exposure to that mycotoxin at any specific concentration.

Lab availability

Some commercial dust testing labs offer this species as an extended-panel option. Specific lab coverage changes over time: check with your laboratory for current panel options.

Related

Penicillium speciesBeyond the 36

References

  1. Meklin T, Haugland RA, Reponen T, Varma M, Lummus Z, Bernstein D, Wymer LJ, Vesper SJ. Quantitative PCR analysis of house dust can reveal abnormal mold conditions. J Environ Monit. 2004;6(7):615–620.
  2. Pitt JI, Hocking AD. Fungi and Food Spoilage. 3rd ed. New York: Springer; 2009.