Safe handling of microbes

The vast majority of microbial life on Earth is harmless to humans, and many microorganisms have beneficial effects. Since the dawn of civilisation, humans have harnessed microbial fermentations to make bread and alcoholic beverages, and to prolong the life of food. Today, technologists are exploiting microorganisms in the pharmaceutical industry, for food production, mineral extraction, the oil industry and in agriculture. There is hardly any aspect of modern life that is not touched by microbiology. However, a small minority of microbes do cause disease, and a minority of disease-causing microbes can cause fatal infections. Some, such as the human immunodeficiency virus, the cause of AIDS, may take several years to exert their lethal effect. Others such as Neisseria meningitidis, the cause of meningococcal meningitis, can kill within hours of the first symptoms of the disease.

When working with microbes, care must be taken to ensure that laboratory cultures do not escape to cause laboratory-acquired infections or to pollute the environment. Equally, it is important to ensure that laboratory cultures do not become contaminated with unwanted extraneous organisms from the environment. If care is not taken to avoid contamination of laboratory cultures, then the results of microbiological experiments are not reliably reproducible, and the data obtained would be unreliable. It is impossible to tell whether the observations made in such experiments are due to the properties of the desired organism, or arise from the activity of a contaminant.