Save All Your Kippers for Me Trivia Quiz

Answer: Microbes

Not all microbes are a problem and in fact there are some (such as yeast) that are used in food preservation. Fungi is mostly bad in food but there are some, for example, which have a role in cheese making and mushrooms (a class of fungi) are a major food group. Generally, though, food preservation is about creating conditions where microbes cannot thrive.

The best result easily achievable is normally to slow down the decay rather than stop it altogether. This may be, for example, by removing water, creating an environment too acidic or alkaline for the microbes, chilling the food, removing air, killing the microbes or a combination of approaches.

Answer: Salami

A slow acidification, triggering a series of chemical reactions, is the process used to change the meat. This is done by encouraging lactic acid bacteria to grow in a controlled manner. The acid is produced as a waste product and coagulates the proteins, reducing its water-holding capacity and hence the potential activity of bacteria and enzymes. Direct acidification, for instance by using vinegar, is not used as it denatures the proteins and results in undesirable texture in the salami.

Answer: Fermentation

Yeast is not the only organism capable of fermenting sugars. In the case of yoghurt, it is bacteria that is required. The main one used is Lactobacillus delbrueckii subsp. bulgaricus which produces lactic acid rather than the alcohol typical of yeast. The lactic acid reacts with milk protein to give the characteristic yoghurt texture. The end result produced will depend on factors such as the animal source of the milk and whether it is raw, pasteurized or homogenized.

Answer: Osmosis

Most pathogenic organisms cannot survive in a salty environment. An edible salt such as sodium chloride is hygroscopic and wicks moisture out of the food cells through osmotic pressure. Corned beef gets its name from the large corns or grains of salt that were used, although nowadays a brine (salt solution) is used commercially.

It was discovered that salt mixed with nitrates (such as saltpeter) would keep the colour of the meat red rather than gray, red being more desirable from a consumer point of view. The protective effect actually comes from bacteria converting nitrates to nitrites so the commercial process tends to use sodium nitrite for better control of the curing process. Bacon is one of those cured in this way, with contributions from smoking and sugaring.

Answer: True

Nitrites, it would seem, can be good or bad for you. They can be converted into carcinogenic nitrosamines or into nitric oxide, which has beneficial effects such as lowering blood pressure. The key factors appear to be whether amines (as found in protein) are present or how it is cooked. So, for example, it is known that high-heat cooking of processed meat produces nitrosamines.

Around 80% of a person's nitrate intake comes from vegetables. Vegetable sources include celery, spinach, beets and lettuce. Mouth bacteria converts these to nitrites.

Answer: Eel

Cheap and nutritious, eels used to be common on the river Thames and formed a staple in London's East End. Deer and swan were more likely seen at royal banquets and snails are more likely to be seen in Mediterranean, African and SE Asian dishes.

Jellied eels are prepared by boiling chopped up eels. The boiling kills microbes and release proteins such as collagen into the liquid. When this cools, it forms a jelly which excludes air from the fish, thus preserving the dish. Other examples of jellying includes traditional pâté, placed in a small pot and finished off with a layer of gelatin.

Answer: Heating

Sometimes called forever soup or hunter's pot, these were associated with mediaeval inns having a cooking pot left on a stove continuously, topped up with liquid and ingredients as necessary. It is a technique also used in some Asian countries. A recent example is of a New York restaurant which ran one for eight months from August 2014.

Answer: Alkalinity

Alkaline salts gradually increase the basicity of the egg - in pH terms, to between 9 and 12 on the scale. This creates an environment too toxic for microbes. It is an alkaline pickling process. The egg yolk becomes dark greenish grey in colour and the white turns to a translucent dark brown. One version produces patterns in the egg white which are likened to pine branches.

These are Songhua eggs and are considered more desirable.

Answer: Root vegetables

A storage clamp is typically a long shallow trench in soil heaped with the crop up to six feet (or just under 2 metres) in height and then covered in several inches of soil. This excludes light and air from the crop as well as keeping it cool. The crop can be recovered from one end as required without disturbing the rest of the crop. Root crops are relatively resistant to spoilage and so do not need much to be kept in condition for a few months. Crops like potatoes, sugar beets and turnips can be stored this way.

Answer: Herring

Kippers are made from herring, a small oily fish, which is butterflied before treatment. The preservation comes from salting or pickling and cold-smoking over wood chips. Traditionally no colouring was used however an economy measure during World War One saw a coal tar dye being used to make up for a shortened smoking process.

These days annatto dye may be used, giving an orange colour instead of the red colour resulting from heavy smoking.