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Techniques to Control the Growth of Microbes

Microbes are an essential and beneficial part of human life. However, while there are useful and beneficial microbes, there are also harmful ones. Understanding how to control microbial growth is important for many reasons, notably in medical settings and in food storage and preparation. Microbial growth can be prevented by removing the materials that microbes need to thrive, and sterilization is a sure way of preventing microbial growth, as it destroys microbes.

  1. Ideal Conditions for Microbe Growth

    • Microbes require certain conditions in order to grow and multiply. Although ideal conditions will vary from species to species, there are some general conditions that are best for most microbes. Microbes prefer pH neutral environments, or conditions that are not strongly acidic or basic. Microbes that cause food poisoning thrive and will multiply at temperatures between 40 and 140 degrees Fahrenheit. Moist environments are more conducive to microbial growth than dry environments. Changing any of these factors prevents microbe growth.

    Chemical Control

    • Many chemicals have antibacterial properties and can be used to sterilize surfaces. Alcohol-based cleaning products are very common and effective. Many other chemicals can be used and have different uses in different situations. For instance, chlorhexidine, iodophor, hexachlorophene and iodine solutions are all used for use on skin prior to surgical procedures. Antibacterial chemicals do not work on all types of microbes and some are very resistant; however, this is a good method of controlling microbial growth.

    Heat

    • Because microbes survive best within a range of temperatures, boiling is a very simple and effective method of killing most types of microbes. Other methods include autoclaving, which uses heat from steam and is recommended for canning low-acid foods, dry heat sterilization, which uses hot air, and pasteurization, which uses several equivalent times and temperatures to kill pathogens. Food products that are pasteurized are not necessarily sterilized. In the reverse, extreme cold can also be used to kill microbes.

    Other Methods of Microbe Control

    • Some substances may not tolerate the extreme heat used to kill many microbes, in which case, filtration is sometimes used. Filtration uses extremely fine membranes to filter out bacteria. Draft beer is a good example of a substance that is treated in this way. Dessication, or complete removal of a water source, can also be effective for many microbes. Salt and sugar are both used as preservatives in part because they remove a water source from microbes. Exposure to radiation is another method of sterilization. The radiation from microwaves and ultraviolet radiation are two familiar forms. The effectiveness of this method varies depending upon the type of radiation and the substance that is being subjected to radiation.

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