10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The CMC exam has 120 questions and runs 3 hours.
These 10 free CMC questions are organized by exam domain, so you can see how each part of the Council-certified Microbial Consultant blueprint is tested. Reveal the answer and explanation under each question.
Microscopy of a tape lift shows intact conidiophores ending in swollen vesicles. Spore-producing cells cover the vesicles and bear chains of conidia. The laboratory has not performed species-level testing. Which genus is most consistent with this morphology?
Correct answer: A - Aspergillus
After disinfection of a bacterially contaminated reservoir, culture counts fall markedly, yet a validated endotoxin-specific assay of residual dust remains positive. Its controls are acceptable. Which residual material explains this finding without requiring viable bacteria?
Correct answer: D - Lipopolysaccharide from Gram-negative bacterial outer membranes
A long-term care facility's Legionella water-management review finds hot-water storage at 52°C and a recirculation return at 43°C. The team will retain point-of-use mixing valves and meet applicable outlet-temperature limits. Which proposed operating targets best address both hot-water control points using CDC guidance?
Correct answer: B - Storage at 65°C; maintain the circulating return at 52°C.
Water repeatedly wets insulation beneath a chilled-water line, but pressure testing shows no pipe leak. Adjacent air has a dew point of 16°C; the exposed pipe surface is 10°C. The room's centrally measured relative humidity is 46%. Which repair best addresses the moisture mechanism shown by these findings?
Correct answer: D - Replace wet insulation and restore a continuous, sealed vapor-retarding jacket.
A hospital proposes removing moldy ceiling tiles beside a hematology unit. The workroom and adjacent corridor share an undivided ceiling return-air plenum. The proposed barrier stops at the suspended ceiling grid, and the contractor cites a satisfactory room-to-corridor pressure reading as evidence of isolation. What revision closes the contamination pathway that this pressure reading does not rule out?
Correct answer: D - Extend isolation to the structural deck and separate the affected return-air pathway.
An office has a persistent musty odor but no visible growth. Simultaneous indoor and outdoor spore-trap samples use the same method and pass quality checks. Indoors: 820 spores/m³ total, including 640 Aspergillus/Penicillium-type. Outdoors: 2,600 spores/m³ total, including 80 Aspergillus/Penicillium-type. The owner says the lower indoor total rules out an indoor source. How should the consultant interpret the comparison?
Correct answer: B - Indoor enrichment of that spore group supports investigating a source despite the lower total.
The field log for a spore-trap sample records 15 L/min for 8 minutes, with acceptable pre- and post-sampling flow checks. The laboratory worksheet lists 18 spores counted in 25% of the deposit and a whole-deposit estimate of 72 spores. No other count corrections are needed. What concentration belongs in the report?
Correct answer: C - 600 spores/m³
After a roof leak is repaired, mold-contaminated gypsum board is removed under containment. The exposed framing is structurally sound and fully accessible, with superficial fungal growth but no decay. The drying plan includes comparison with unaffected framing of the same material. What should the remaining framing's remediation specification require?
Correct answer: C - Physically clean the wood, HEPA-vacuum residue, and verify the specified drying endpoint.
A 20 ft by 15 ft by 10 ft containment requires at least 6 outdoor exhaust air changes per hour. A HEPA exhaust unit rated at 500 cfm delivers 250 cfm through its installed duct. A second unit recirculates 350 cfm entirely inside the enclosure. Independent pressure checks meet the project's pressure criterion. Which assessment of the exhaust requirement is correct?
Correct answer: A - Actual exhaust is 5 ACH; at least 50 cfm more measured exhaust is needed.
Before a microbial inspection of a below-grade utility vault, remote testing at sea level shows 18.0% oxygen at the intended work level. The meter passes its checks; combustible-gas readings are below alarm levels. No entry or rescue plan has been established. A supervisor proposes a full-face powered air-purifying respirator for a five-minute inspection. The consultant should:
Correct answer: A - Prevent entry until the atmosphere and appropriate entry/rescue controls have been addressed.
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