Gloucester cheese. These and subsequent investigations, notably those
sponsored by the journalLancet, led directly to the introduction of the
first British Food and Drugs Act in 1860. Despite the protection of a
much stricter regulatory framework, occasional triumphs of human
cupidity are still recorded today. Further examples include the use of
ethylene glycol in some Austrian wines, the intrepid entrepreneur who
sold grated umbrella handles as Parmesan cheese and the grim case of the
Spanish toxic cooking oil scandal which killed or maimed hundreds.
Although some would regard all chemical additions to food as syn-
onymous with adulteration, many are recognized as useful and are
allowed. Additives may be used to aid processing, to modify a food’s
texture, flavour, nutritional quality or colour but, here, we are concerned
with those which primarily effect keeping quality: preservatives.
Preservatives are defined as ‘substances capable of inhibiting, retard-
ing or arresting the growth of micro-organisms or of any deterioration
resulting from their presence or of masking the evidence of any such
deterioration’. They do not therefore include substances which act by
inhibiting a chemical reaction which can limit shelf-life, such as the
control of rancidity or oxidative discolouration by antioxidants. Neither
does it include a number of food additives which are used primarily for
other purposes but have been shown to contribute some antimicrobial
activity. These include the antioxidants, butylated hydroxytoluene
(BHT) and butylated hydroxyanisole (BHA), and the phosphates used
as acidity regulators and emulsifiers in some products.
Preservatives may be microbicidal and kill the target organisms or
they may be microbistatic in which case they simply prevent them
growing. This is very often a dose-dependent feature; higher levels of
an antimicrobial proving lethal while the lower concentrations that are
generally permitted in foods tend to be microbistatic. For this reason
chemical preservatives are useful only in controlling low levels of con-
tamination and are not a substitute for good hygiene practices.
Recently consumers have shown an inclination to regard preservatives
as in some way ‘unnatural’, even though the use of salts, acid, or smoke
to preserve foods goes back to the beginning of civilization. Usage of
chemical preservatives is now more restricted and controlled than ever
and in many areas it is declining. It is perhaps well to remember though
that only the fairly recent advent of technologies such as canning and
refrigeration has allowed us any alternative to chemical preservation or
drying as a means of extending the food supply.
4.5.1 Organic Acids and Esters
The most important organic acids and esters that are used as food
preservatives are listed in Table 4.12 along with their E-numbers (EU
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