Contamination and release prevention protocol

Contamination is the unwanted presence of a microorganism in a particular environment. That environment can be in the laboratory setting, for example, in a medium being used for the growth of a species of bacteria during an experiment. Another environment can be the human body, where contamination of various niches can produce an infection. Still another environment can be the solid and liquid nutrients that sustain life. A final example, which is becoming more relevant since the burgeoning use of biotechnology , is the natural environment. The consequences of the release of bioengineered microorganisms into the natural environment to the natural microflora and to other species that depend on the environment for their welfare, are often unclear.

The recognition of the adverse effects of contamination have been recognized for a long time, and steps that are now a vital part of microbiological practice were developed to curb contamination. The prevention of microbial contamination goes hand in hand with the use of microorganisms.

Ever since the development of techniques to obtain microorganisms in pure culture , the susceptibility of such cultures to the unwanted growth of other microbes has been recognized. This contamination extends far beyond being merely a nuisance. Differing behaviors of different microorganisms, in terms of how nutrients are processed and the by-products of this metabolism , can compromise the results of an experiment, leading to erroneous conclusions.

In the medical setting, microbial contamination can be life threatening. As recognized by Joseph Lister in the mid-nineteenth century, such contamination can be lessened, if not prevented completely, by the observance of various hygienic practices in the hospital setting. In modern medicine and science, the importance of hand washing and the maintenance of a sterile operating theatre is taken for granted.

Prevention of microbiological contamination begins in the laboratory. A variety of prevention procedures are a common part of an efficient microbiology laboratory. The use of sterile equipment and receptacles for liquid and solid growth media is a must. The prevention of contamination during the manipulations of microorganisms in the laboratory falls under the term asceptic technique. Examples of asceptic technique include the disinfection of work surfaces and the hands of the relevant lab personnel before and after contact with the microorganisms and the flaming of the metal loops or rods used to transfer bacter from one location to another.

In other areas of a laboratory, microorganisms that are known to be of particular concern, because they can easily contaminate or be contaminated, or because they represent a health threat, can be quarantined in special work areas. Examples of such areas include fume hoods and the so-called glove box. The latter is an enclosed space where the lab worker is kept physically separate from the microorganisms, but can manipulate the organisms by virtue of rubber gloves that are part of the wall of the enclosure.

In both the laboratory and other settings, such as processing areas for foods, various monitoring steps are instituted as part of a proper quality control regimen to ensure that contamination does not occur, or can be swiftly detected and dealt with. A well-established technique of contamination monitoring is the air plate technique, where a non-specific growth medium is exposed to the circulating air in the work area for a pre-determined period of time. Air-borne microorganisms can be detected in this manner. More recently, as the importance of the adherent (biofilm) mode of growth of, in particular, bacteria became recognized, contamination monitoring can also include the installation of a device that allows the fluid circulating through pipelines to be monitored. Thus, for example, water used in processing operations can be sampled to determine if bacterial growth on the pipeline is occurring and also whether remediation is necessary.

A necessary part of the prevention of microbiological contamination is the establishment of various quality control measures. For example, the swiping of a lab bench with a sterile cotton swab and the incubation of the swab in a nonspecific growth medium is a regular part of many microbiology laboratories quality control regimen. The performance of all equipment that is used for sterilization and microorganism confinement is also regularly checked.

With the advent of biotechnology and in particular the use of genetically modified microorganisms in the agricultural sector, the prevention of the unwanted release of the bioengineered microbes into the natural environment has become an important issue to address.

The experimentation with genetically engineered microorganisms in the natural environment is subject to a series of rigid controls in many countries around the world. A series of benchmarks must be met to ensure that an organism is either incapable of being spread or, if so, is incapable of prolonged survival.

Prevention of genetic contamination, via the exchange of genetic material between the bioengineered microbe and the natural microbial population, is difficult to prevent. However, available evidence supports the view that the genetic traits bred into the bioengineered organism to permit its detection, such as antibiotic resistance , are not traits that will be maintained in the natural population. This is because of the energy cost to the microorganism to express the trait and because of the mathematical dynamics of population genetics (i.e., the altered genes are not present in numbers to become established within the greater population) and the absence of the need for the trait (the antibiotic of interest is not present in the natural environment). Hence, contamination prevention procedures have tended to focus on those aspects of contamination that are both relevant and likely to occur.

As an example of the measures currently in place, the United States has three agencies that are concerned with the regulation of biotechnology. These are the Department of Agriculture, Environmental Protection Agency, and the Food and Drug Administration. Each of these agencies oversee regulatory legislation that addresses the contamination of various natural and commercially relevant environments.

See also Asilomar conferences; Biotechnology; Hazard Analysis and Critical Point Program (HACPP); Laboratory techniques in microbiology