quick vinegar generators appears to be less affected as their acetification
rate may slow but rarely stops. This is probably due to the greater
heterogeneity of the culture present which allows organisms of different
phage susceptibility to take over in the event of phage attack.
Where legal definitions of vinegar exist, it is specified as a fermentation
product. ‘Artificial vinegars’ made by diluting and colouring acetic acid
are thus excluded and, in the UK, have to be known rather laboriously as
‘non-brewed condiment’. Although vinegar can be made up to 14%
acidity, it is usually diluted down to an appropriate strength for bottling.
The minimum acetic acid content is usually prescribed to be something
between 4 and 6% w/v, but higher strength vinegars are available for
pickling.
Though most often thought of in terms of its use as a condiment,
vinegar is an important food ingredient. It is used as a preservative and
flavouring agent in a large and expanding range of products such as
mayonnaise, ketchups, sauces and pickles. In the United States only
about 30% of the vinegar produced is sold as table vinegar, the rest being
used in food processing.
The antimicrobial action of organic acids such as acetic acid has
already been discussed (see Section 3.2.2) and the use of vinegar in a
formulated product usually restricts the spoilage microflora to yeasts,
moulds and lactobacilli. Vinegar preserves were one of the earliest areas
where predictive models were developed (see Chapter 3). Work at what
became the Leatherhead Food Research Association indicated that to
achieve satisfactory preservation of a pickle or sauce a minimum of 3.6%
acetic acid, calculated as a percentage of the volatile constituents, is
necessary. That is to say:
% acetic acid on whole product¼ 0 : 036 % volatile constituents ð 9 : 3 ÞA different formula has been described specifically for sweet cucumber
pickles:
% acetic acid on whole product¼ð 80 SÞ= 20 ð 9 : 4 Þwhere S is the % sucrose on the whole product.
More elaborate formulae have been produced which apply to emulsi-
fied and non-emulsified sauces. These are based largely on work con-
ducted at the laboratories of Unilever in the Netherlands and are known
as the CIMSCEE code, after the French acronym of the European
Sauces Trade Association. The code consists of two formulae; one to
determine the potential for spoilage by acetic acid tolerant yeasts,
moulds and LAB, and another derived from inactivation rates of sal-
monella to assess microbiological safety. Each contains terms for salt,
sugar, and acetic acid content and pH. If, when the relevant values are
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