Microbial Sterilization Methods Quiz

Depends on the time it takes to eliminate a population of microbes, which is affected by the number of microbes, microbial species' susceptibility (e.g., endospores), organic matter interfering with treatments, and exposure time.

The lowest temperature that kills all cells in a culture within 10 minutes.

The time needed to kill all cells in a culture at a specific temperature.

Time required to kill 90% of a microbial population at a set temperature.

A highly dependable sterilization method using steam under pressure that denatures proteins.

A device that uses steam under pressure for sterilization.

A heat treatment process that significantly reduces the number of spoilage and pathogenic microorganisms, but does not sterilize.

Prion destruction requires higher temperatures (132°C) and longer durations (4.5 hours) than typical autoclave conditions to fully eliminate them.

Complete elimination of all microbial life, including spores, from an object or surface.

Process that eliminates most pathogenic microbes, but not necessarily all microbes or spores.

Application of antimicrobial agents to living tissue to prevent infection.

Reduction of microbial populations to safe levels, often used for food preparation surfaces.

Graphical representation of the logarithmic decline in microbial population over time when exposed to a lethal agent.

Physical removal of microbes by passing a liquid or gas through a filter with pores too small for microbes to pass.

A sterilization method that kills microorganisms through oxidation.

A sterilization method that uses dry heat at high temperatures (170˚C) for a period of time.

A sterilization method that uses moist heat (121˚C) under pressure for a short time (15 minutes).

A sterilization method using filters to remove microbes (e.g. HEPA filters).

Slows down microbial growth by inhibiting enzymatic reactions, damaging microbes with ice crystals.

A process that denatures bacterial proteins in liquids, preserving food flavor.

A process that prevents microbial metabolism by drying out the microorganism.

A sterilization method that uses high-energy radiation to damage microbial DNA.

An increase in the number of microbial cells, not their size.

The temperature at which a microbe grows best.

Microbes that thrive in cold temperatures, with an optimum growth temperature below 15°C.

Microbes that grow best at moderate temperatures, with an optimum growth temperature between 20°C and 45°C.

Microbes that thrive in hot temperatures, with an optimum growth temperature between 45°C and 70°C.

Most bacteria grow best at a neutral pH (6.5-7.5), while some thrive in acidic or alkaline environments.

The pressure exerted by the concentration of solutes in a solution, impacting water movement into or out of microbial cells.

An environment with a higher solute concentration than the inside of a cell, causing water to move out, potentially leading to plasmolysis.

Microbes that require high salt concentrations to survive.

Microbes that can tolerate high salt concentrations but don't require them.

Carbon is essential for microbial growth, making up about half of a microbe's dry weight.

Microbes that obtain their energy from organic compounds like sugars and proteins.

Nitrogen is crucial for building amino acids and proteins, which are essential for microbial structure and function.

Sulfur is essential for building certain amino acids and vitamins necessary for microbial growth.

Phosphorus is crucial for building nucleic acids (DNA and RNA) as well as ATP (the energy currency of cells).

Microbes have different oxygen requirements, some needing it, some tolerating it, and some avoiding it.

Microbes that require oxygen to survive.

Microbes that don't require oxygen and may even be harmed by it.

Microbes that can grow with or without oxygen, but prefer oxygen.

Certain oxygen-containing molecules can be harmful to cells, such as singlet oxygen, superoxide radicals, and hydroxyl radicals.

Complex microbial communities encased in a sticky matrix, often attached to surfaces.

A communication system used by bacteria to coordinate their behavior and create biofilms.

Nutrients prepared for microbial growth, typically sterilized to avoid contamination.

Culture media with a precisely known chemical composition.

Culture media containing extracts or digests of yeast, meat, or plants, with an unknown exact composition.

A complex polysaccharide used as a solidifying agent in culture media, allowing microbes to grow on a solid surface.

Techniques used to grow microbes that cannot tolerate oxygen, typically using reducing media or anaerobic jars.

Bacteria that require high CO2 levels, often resembling conditions found in body tissues.

Culture media containing additives that suppress the growth of unwanted microbes and encourage the desired ones.

Culture media that allow for the differentiation of different types of microbes based on visible changes in colony appearance.

Culture media that encourages the growth of a desired microbe while suppressing others, often used for isolating specific microbes from a mixed population.

A culture containing only one species or strain of microbe, separated from other organisms.

A technique used to isolate individual colonies of bacteria from a mixed culture by streaking the sample across an agar plate.

A visible cluster of microbes on a solid medium arising from a single cell or group of attached cells.

Methods used to store bacterial cultures for extended periods, such as deep-freezing or freeze-drying.

The most common method of bacterial cell division, where a single cell divides into two identical daughter cells.

The time it takes for a microbial population to double in size.

A graphical representation of the stages of microbial growth in a closed culture system.

A method to directly count microbes using a microscope and a counting chamber.

A technique used to dilute a sample of microbes repeatedly, allowing for accurate counting of colonies on agar plates.

A method to indirectly measure microbial growth by measuring the turbidity (cloudiness) of a culture.

The initial phase of bacterial growth where cells are adjusting to their new environment and preparing for growth, resulting in little to no increase in population size.

The phase of rapid, exponential growth where bacteria divide at a constant rate, doubling in number with each generation.

The phase of growth where the rate of cell division equals the death rate, leading to a stable population size.

The phase where bacteria start dying off faster than they're reproducing, leading to a decrease in the population size.

A method for counting viable bacteria by diluting a sample and plating it on agar, where each colony grows from a single bacterium.

Bacteria require essential nutrients like carbon, nitrogen, phosphorus, sulfur, water, and specific inorganic ions like potassium, magnesium, and calcium, for growth. They also need trace elements and organic growth factors like vitamins.

Biofilms are communities of bacteria that stick together and form a thick, slimy layer on a surface. They often form on surfaces like teeth, medical implants, and food processing equipment.

Essential nutrients are compounds that a microbe cannot synthesize on its own and must obtain from its environment. They include carbon, nitrogen, sulfur, phosphorus, minerals, and sometimes growth factors like vitamins.

A culture medium is a carefully prepared mixture of nutrients designed to support the growth of microbes in a laboratory setting. It can be solid or liquid and contains all the components needed for bacterial growth.

Toxic forms of oxygen are highly reactive molecules that can be harmful to cells. These include singlet oxygen, superoxide free radicals, peroxide anions, and hydroxyl radicals.

An inoculum is a small sample of microbes introduced into a culture medium to start a new culture.

A selective medium is a type of culture medium that only allows certain types of microbes to grow, while inhibiting the growth of others.

A differential medium is a type of culture medium that allows different types of microbes to be distinguished based on how they grow on the medium.

Bacteria have different oxygen requirements. Some need oxygen (aerobes), some don't need it and may be harmed by it (anaerobes), and some can grow with or without it (facultative anaerobes).

Sterile in microbiology means free from living microbes. Culture media must be sterile to prevent unwanted microbes from contaminating the desired culture.