Sterilization Questions: Microbiology Quiz!

1. Ethylene oxide gas is highly explosive in mixtures of >3.6% v/v in air.

True

False

Ethylene oxide gas is highly explosive in mixtures of >3.6% v/v in air. This means that if the concentration of ethylene oxide gas in the air is higher than 3.6% by volume, it can easily ignite and explode. This highlights the extreme danger associated with ethylene oxide gas and emphasizes the need for proper handling and storage measures to prevent accidents and ensure safety.

Explanation

Ethylene oxide gas is highly explosive in mixtures of >3.6% v/v in air. This means that if the concentration of ethylene oxide gas in the air is higher than 3.6% by volume, it can easily ignite and explode. This highlights the extreme danger associated with ethylene oxide gas and emphasizes the need for proper handling and storage measures to prevent accidents and ensure safety.

2. The initial microbial contamination level influences the time-dependent process( elimination of viable microorganisms)

True

False

The initial microbial contamination level has an impact on the time it takes to eliminate viable microorganisms. Higher levels of contamination may require more time and effort to completely eliminate the microorganisms, while lower levels may be easier and quicker to eliminate. This suggests that the initial contamination level plays a role in the time-dependent process of eliminating viable microorganisms.

Explanation

The initial microbial contamination level has an impact on the time it takes to eliminate viable microorganisms. Higher levels of contamination may require more time and effort to completely eliminate the microorganisms, while lower levels may be easier and quicker to eliminate. This suggests that the initial contamination level plays a role in the time-dependent process of eliminating viable microorganisms.

3. The elevated temperatures generally associated with moist heat sterilization methods can only be achieved by:

Pure ethylene oxide gas

S broad-spectrum biocidal activity

Oxidative processes

Generation of steam under pressure

The correct answer is the generation of steam under pressure. Moist heat sterilization methods, such as autoclaving, rely on the generation of steam under pressure to achieve elevated temperatures. This process effectively kills microorganisms by denaturing proteins and disrupting cell membranes. Pure ethylene oxide gas is used in another type of sterilization method called gas sterilization. While ethylene oxide gas also has broad-spectrum biocidal activity, it does not rely on elevated temperatures. Oxidative processes can be involved in sterilization methods, but they are not specific to moist heat sterilization.

Explanation

The correct answer is the generation of steam under pressure. Moist heat sterilization methods, such as autoclaving, rely on the generation of steam under pressure to achieve elevated temperatures. This process effectively kills microorganisms by denaturing proteins and disrupting cell membranes. Pure ethylene oxide gas is used in another type of sterilization method called gas sterilization. While ethylene oxide gas also has broad-spectrum biocidal activity, it does not rely on elevated temperatures. Oxidative processes can be involved in sterilization methods, but they are not specific to moist heat sterilization.

4. Which of the following is INCORRECT:

Trapping within the matrix of the filter material is one of the mechanisms of filtration

The principal application of sterilizinggrade filters related to the venting systems on fermenters

Filtration sterilization cannot be used for the clarification and sterilization of liquids and gases.

UV light used in the sterilization of the treatment of manufacturing-grade water.

Filtration sterilization can indeed be used for the clarification and sterilization of liquids and gases. This method involves passing the liquid or gas through a filter that traps and removes microorganisms, thereby clarifying and sterilizing the substance. Therefore, the statement that filtration sterilization cannot be used for clarification and sterilization of liquids and gases is incorrect.

Explanation

Filtration sterilization can indeed be used for the clarification and sterilization of liquids and gases. This method involves passing the liquid or gas through a filter that traps and removes microorganisms, thereby clarifying and sterilizing the substance. Therefore, the statement that filtration sterilization cannot be used for clarification and sterilization of liquids and gases is incorrect.

5. Which of the following is INCORRECT:

Pure ethylene oxide gas can be used below atmospheric pressure in sterilizer chambers from which all air has been removed

Formaldehyde limits the packaging materials that can be employed to principally paper and cotton fabric.

Formaldehyde cannot normally be detected by smell at concentrations lower than those permitted in the atmosphere

Ethylene chlorohydrin are potentially mutagenic and carcinogenic

Formaldehyde can be detected by smell at concentrations lower than those permitted in the atmosphere.

Explanation

Formaldehyde can be detected by smell at concentrations lower than those permitted in the atmosphere.

6. Ethylene oxide sterilization needs a higher temperature than formaldehyde.

True

False

Ethylene oxide sterilization does not necessarily require a higher temperature than formaldehyde. The temperature required for sterilization depends on various factors such as the type and size of the item being sterilized, the desired level of sterilization, and the specific sterilization method being used. While ethylene oxide sterilization typically involves lower temperatures, formaldehyde can also be used at lower temperatures for certain applications. Therefore, the statement that ethylene oxide sterilization requires a higher temperature than formaldehyde is false.

Explanation

Ethylene oxide sterilization does not necessarily require a higher temperature than formaldehyde. The temperature required for sterilization depends on various factors such as the type and size of the item being sterilized, the desired level of sterilization, and the specific sterilization method being used. While ethylene oxide sterilization typically involves lower temperatures, formaldehyde can also be used at lower temperatures for certain applications. Therefore, the statement that ethylene oxide sterilization requires a higher temperature than formaldehyde is false.

7. Which of the following is CORRECT regarding Sterilizer design and Sterilizer operation.

Shelves within the chamber are perforated to prevent cool spots developing inside the chamber.

A fixed temperature sensor connected to a chart recorder provides a permanent record of the sterilization cycle.

Appropriate door-locking controls should be incorporated to shorten the heating-up stage

A fan is fitted to the rear of the oven to prevent interruption of a sterilization cycle once begun

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Explanation

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8. Which of the following is CORRECT:

Porous loads (i.e. dressings) are of the types of ‘portable’ sterilizers

large-scale sterilizers generally have internal electric heaters

Bottled fluid sterilizers employing a minimum temperature of 121°C.

‘portable’ sterilizers, for routine hospital or industrial use

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Explanation

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9. Which of the following is CORRECT:

Radiation sterilization is generally applied to articles in the aqueous state

Radiation sterilization has not proved to be a method of industrial sterilization of heat-sensitive products.

In the case of UV light , mould spores prove to be most resistant

Electron or gamma-irradiation is not as efficient a sterilization method as UV irradiation

Mould spores are known to be highly resistant to UV light, making them the most resistant when it comes to sterilization using UV light. This implies that other microorganisms may not be as resistant and can be effectively sterilized using UV light.

Explanation

Mould spores are known to be highly resistant to UV light, making them the most resistant when it comes to sterilization using UV light. This implies that other microorganisms may not be as resistant and can be effectively sterilized using UV light.

10. Dry heat sterilization used for hydrogenation of glassware.

True

False

Dry heat sterilization is a method used to sterilize glassware by exposing it to high temperatures in the absence of moisture. It is not used for hydrogenation, which is a chemical reaction that involves the addition of hydrogen to a compound. Therefore, the statement is false.

Explanation

Dry heat sterilization is a method used to sterilize glassware by exposing it to high temperatures in the absence of moisture. It is not used for hydrogenation, which is a chemical reaction that involves the addition of hydrogen to a compound. Therefore, the statement is false.