Microbiology is a major part of food science. We've all heard of E. coli and Salmonella (the naughty microbes) and are aware of the roles that micro plays in food safety but microorganisms also play crucial roles in different aspects of food science, such as in food production, as you'll see below.
The term fermentation is derived from the latin word fermentare meaning "to ferment". The fact that the Romans had a word for the process should say enough - fermentation has been around for a long time!
Fermentation is the anaerobic (without oxygen) process of converting sugars into alcohols or acids and carbon dioxide by microorganisms, such as yeast or bacteria. It forms the basis for brewing beer, making wine and vinegar and culturing milk to make yoghurt. It is an ancient process, for example, used on olives to achieve the characteristic textures and flavours associated with this fruit. The earliest wine was found in Georgia and dates back to 6000 B.C. - talk about vintage! It is also used by modern biotechnologists to create biomass using micro-organisms which can produce useful materials such as drugs, flavours or enzymes.
Yeast extract, also called 'autolysed yeast extract', is the substance that results from the breakdown of yeast cells. The commercial process begins by adding sodium chloride (salt) to brewer's yeast. The addition of salt causes the yeast cells to shrivel up and undergo autolysis, basically self-destruct. During autolysis, the yeast's digestive enzymes break down its proteins into smaller constituents, namely amino acids and peptides. After this process is complete, the cell walls and other insoluble compounds are removed and what remains is concentrated, then pasteurised. In the UK, autolysed yeast extract is most popular in a spread form, such as Marmite.
Food safety for ready meals
Food safety is especially important for ready meals, as they pose unique microbiological risks. Ready meals are often made up of a number of different ingredients, all of which must be traceable and checked that they meet essential food standards. The final product is then assembled, sometimes by hand, before it is packaged. Hygiene is crucial, as some of the ingredients will be handled and then eaten with no processing steps in between.
Different products fall under different risk categories depending on whether they are 'ready to eat',' ready to reheat' or 'ready to cook'. If a product is 'ready to eat', it will not be cooked or undergo any other form of processing that would reduce or eliminate microorganisms to an acceptable level. Therefore, suppliers must heavily rely on precautionary methods, such as a Hazard Analysis and Critical Control Points (HACCP) plan, to ensure that all of a product's components are safe for human consumption, beginning at the farm through to the moment that a consumers takes the first bite.