WJEC Level 3 Certificate in Food Science and Nutrition

Colonies of bacteria cultured on an agar plate Structure of a bacterial cell 7 ⦁ Moulds are involved in the production of miso, cheese, chocolate, soy sauce, tempeh, salami and wine ⦁ Yeasts are involved in the production of bread, cider, beer, wine, yeast extract (e.g. Marmite), meat sausages, hams, coffee and cocoa /chocolate. Bacteria Bacteria are single-celled organisms that can only be viewed in detail under a powerful microscope. There are thousands of different types of bacteria and they come in different shapes and sizes, as shown below. Bacteria are so small that several hundreds of thousands of them can fit into an area the size of the full stop at the end of this sentence. This makes it impossible to see them in food by just looking at it, making it very difficult to know if a food is contaminated with bacteria or not. It is only possible to see a colony of many millions of bacteria with the naked eye, which appear as different coloured spots and patches. Bacteria cells have a number of features that explain why they are so successful in causing food spoilage and food poisoning, as shown in this cross-section of a typical bacterium (one) cell: ⦁ The capsule protects bacteria from drying out and from chemicals that are meant to destroy them. ⦁ The pili enable bacteria to stick to food and the gut wall inside the body. ⦁ The flagellum (in some bacteria) enables them to move through foods (especially fluids) and in the body. Micro-organisms