Manufacture

Microbial fermentations have been used for centuries to produce foods such as cheese and yoghurt and alcoholic beverages like wine and beer.

Microbiologists are also needed at all stages of modern food and drink manufacturing processes. They are involved in the maintenance of the microbial culture (the inoculum) that is used to start the fermentation of the milk or grape juice, to prevent deterioration of existing strains and to develop or improve existing ones.

Olives and some processed meats are made by fermentation. However, the best known fermented products are beer, wine and spirits - the brewing industry is a major commercial force employing many microbiologists. Some beers are still produced by traditional methods, but in the main, brewing is a strictly controlled operation. Microbiologists maintain the strains of yeasts used and produce improved strains, as well as supervising the fermentation. They also have to solve the problem of dealing with waste materials produced by the process.

Our food contains many other, less obvious, microbial products, such as flavours and colours. Many factory-produced foods lose important vitamins during processing, and to keep our diet healthy, vitamins are added back to the food (e.g. breakfast cereals). These vitamins are made by high yielding bacterial strains and are a relatively inexpensive ingredient.

Safety & hygiene

As we store food for longer periods, it becomes more difficult to prevent spoilage by microbes. Some spoilage just makes food look unattractive but food poisoning is caused by human pathogens such as Salmonella growing on food. The increased demand for production and storage of ready meals, has caused in a rise in the number of cases of food poisoning by the bacteria Listeria and Campylobacter.

Microbiologists are employed in quality control to ensure that products are safe and wholesome; in product development and basic research into food hygiene and preservation.

Water

We need plenty of good quality water for domestic and industrial purposes. Rivers and reservoirs supply water to purification plants where microbiological and chemical tests are carried out to check its quality before distribution. The action of bacteria and protozoa in sewage treatment plants breaks down waste material so that effluent can safely be released back into the rivers. Microbiologists in water companies and the Environment Agency monitor and control these processes.