PRESERVATION HALL OF FAME
Food goes off remarkably quickly without preservatives. The environment is swarming in
bacteria waiting for their chance to colonise every possible niche.
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Preservation began with traditional
processes, no less chemical in their effects for that: salt, wood smoke, resin in wines
Many foods go off appallingly quickly without preservatives and wastage of food between
the field and the table is still a problem (in Russia, with its huge size and poor
infrastructure it is one of the country's main problems). Many of the moulds that grow on
decaying food are dangerous: the most notorious case in food history is the fungus ergot
which used to grow on rye bread causing mass epidemics hallucinogenic delusions.
Traditional preservatives have been used for centuries to combat the decay of foods.
Wood smoke was the first, followed by vinegar, and honey. Traditional preservatives, such
as smoking, salt and vinegar are still used and they do not, of course, have E-numbers.
Smoking is actually the most dubious of methods because smoke contains a large number of
polycyclic hydrocarbons, many of which are known carcinogens.
Preservatives work by killing or stopping the growth of microorganism. All organisms
require a narrow range of conditions in which to live: too acid or too sweet and nothing,
not even bacteria can live (it might seem surprising that sugar is a preservative, but
jam, so long as water doesn't settle out is far too sweet for bacteria, plaques of mould
on jam occur where water has formed on the surface, significantly diluting the
concentration of sugar). Sulphur dioxide, the most widely used preservative, has actually
been in use since the Middle Ages.
The more modern preservatives such as potassium sorbate and sodium benzoate are
specific inhibitors of bacteria, in effect they are broad-spectrum antibiotics. Most of
the preservatives are simple chemicals, very closely related to natural substances;
benzoic acid (E210) for example, occurs in several fruits (including the Scandinavian
Cloudberry which has 50 times the legal limit of benzoic acid) and it is widely used in
fruit preservation. Sorbic acid, E200, the most widely used preservative, is an
unsaturated acid found in some plants. Nisin (E234) which is a natural substance occurring
in milk and Cheddar and Cheshire cheeses. Propionic acid is a simple acid closely related
to vinegar and it is used in bread manufacture as a more effective preservative than
vinegar. Ironically, vinegar as a traditional preservative does not have an E number,
propionic acid does: E280. Consumers may feel more comfortable with vinegar than E280 but
this is totally irrational. Preservatives work by preventing the formation of
microorganisms, some of which are exceedingly dangerous. Preservatives themselves are
generally safe.
There is some concern about the use of sodium nitrite, used in meat preservation.
During cooking nitrites produce nitrosamines, which are known carcinogens. It seems likely
that the body has ways of neutralizing nitrosamines but processed meats preserved with
nitrite now have added vitamins C and E, antioxidants which prevent the formation of
nitrosamines, just to be sure. Nitrosamines are also produced in green vegetables. |
