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Chemical Indicator Function — MFDS Part 1 MCQ

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ModerateMicrobiologyChemical Indicator FunctionMFDS Part 1

During the decontamination of dental instruments, a colour-changing marking is used to distinguish packs that have passed through a steam-sterilizer cycle from packs that have not. It does not, by itself, demonstrate that sterilizing conditions were achieved throughout the load. Which monitoring device is being described?

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Correct answer: D — External Class 1 chemical process indicator on sterilization tape or a pouch

An external Class 1 chemical process indicator changes appearance after exposure to the sterilization process and helps distinguish processed from unprocessed packs. It does not establish that the required conditions were achieved throughout the load or that every instrument is sterile; cycle records, validation and routine testing remain necessary. A biological indicator assesses sterilizer efficacy using resistant spores rather than serving as an external process marker. A Bowie-Dick test evaluates air removal and steam penetration in a vacuum sterilizer and is not a routine pack-exposure label. ATP bioluminescence assesses residual organic contamination or cleaning effectiveness, while pH paper measures acidity or alkalinity and has no role in monitoring steam sterilization.

Reference: NHS England. Health Technical Memorandum 01-05: Decontamination in primary care dental practices, sections 4.11, 4.16 and 4.28. 2013; publication page updated 2024. https://www.england.nhs.uk/wp-content/uploads/2021/05/HTM_01-05_2013.pdf