Food Protection Trends - January/February 2022 - 83

The concept of pH is important for the classifications
of these foods. Throughout the lifetime of this rule, the
distinction between an acid food and an acidified food has
been somewhat convoluted. If one looks at the types of
product examples that are deemed acidified and the examples
of product failures that are presented in the preambles and the
final rules, it can be discerned the rule is intended to apply to
those products that are susceptible to the potential of improper
acidification. Similarly, by examining the types of products
that are " excluded " from the rule and, thus, not considered
acidified foods (e.g., carbonated beverages, jams, jellies,
preserves, standardized and nonstandardized food dressings,
condiment sauces), the shared trait of these products is that
they do not contain large, low-acid particulates and they reach
an equilibrium pH in a relatively short time. Products with
particulates can require a significant pH equilibrium time and/
or can result in a pH greater than 4.6, which are the kinds of
products the rule addresses.
The preambles and the rules focus on products that
" may be called, or may purport to be, 'pickles' or 'pickled
___.' " (5) In other words, the rule is meant to be applied
to products that consist of solid foods, such as cucumbers,
peppers, hearts of palm, and the like, to which acid is added
and for which a significant amount of time is required for
the acid to diffuse into the food and ultimately reach a pH
equilibrium throughout the product. These are the types of
products that are cited in the preambles to the rules as the
reason for the rules.
In the manufacturing of all of the products cited in the
preambles and the final rules, there is a significant amount of
time for the acid to diffuse into the low-acid particulate(s).
As the acid diffuses from the liquid phase into the low-acid
particulate(s), the pH of the liquid phase may go up as the
pH of the particulate goes down. After a period of time, the
liquid phase and the particulate(s) will reach equilibrium pH.
If the finished product equilibrium pH is above 4.6, there
could be a food safety concern due to improper acidification.
Therefore, with these products it is important not only to add
the correct amount of acid but also to ensure that the proper
finished equilibrium pH has been achieved.
In the preamble to Part 128g, the FDA noted that between
1899 and 1964 there were 29 reported outbreaks of botulism
in " home canned pickled beets, peppers, pimentos and
pickles " (2). The FDA further notes that from January
1972 through December 1975, there were two commercial
botulism outbreaks from acidified foods: one from peppers
and one from marinated mushrooms. In the same period,
there were a total 36 recalls. Of these, 34 were due to
improper acidification, which involved peppers, pimentos,
and hearts of palm, whereas the other 2 recalls " involved
filth " (2). Incidents after December 1975 are noted in the
1979 preamble to Part 108 (3). Two additional botulism
outbreaks were mentioned. These outbreaks were due to
improper acidification of canned, acidified sweet cherry
peppers in 1976 and " improperly acidified and processed
food " in 1977. All the acidified foods implicated in the recalls
or botulism outbreaks that were cited in the preambles to the
rules were those that contained low-acid particulates.
The important food safety criterion for an acidified food
is that " a finished equilibrium pH value of 4.6 or lower
is achieved within the time designated in the scheduled
process and maintained in all finished foods " (5). This
criterion indicates that a significant pH equilibrium time
is an important characteristic of an acidified food, along
with the finished equilibrium pH value. If a food does not
fit the type of food cited in the rules and preambles and
does not have a significant pH equilibrium time, then the
food could be considered an acid food. Because all of the
improperly acidified foods cited in the preambles to the
rules are particulate foods with extended pH equilibrium
times, one can logically conclude that particulates and
extended pH equilibrium times are important considerations
in the determination of what constitutes an acidified food.
Additional consideration should also be given to products
for which the amount of acid needed to be added is variable
due to some compositional aspects of the food.
Given the conditions that determine an acidified food,
then one can also logically conclude that products with
few or no solid components, such as teas, vegetable juices,
sweetened or unsweetened flavored beverages, many
barbeque sauces, condiments, and dressings, that come to
pH equilibrium relatively quickly and consistently could
be considered acid foods. Because these foods do not
exist until all the ingredients are mixed, they do not fit the
definition of acidified foods as " low-acid foods to which
acid(s) or acid food(s) are added " (5). These products are
referred to as formulated acid foods.
Acidified foods definition
The definition of an acidified food is provided in 21 CFR
Part 114.3(b): " Acidified foods means low-acid foods to which
acid(s) or acid food(s) are added; these foods include, but
are not limited to, beans, cucumbers, cabbage, artichokes,
cauliflower, puddings, peppers, tropical fruits, and fish, singly
or in any combination. They have a water activity (aw
) greater
than 0.85 and have a finished equilibrium pH of 4.6 or below.
These foods may be called, or may purport to be, 'pickles'
or 'pickled ______.' Carbonated beverages, jams, jellies,
preserves, acid foods (including such foods as standardized
and non-standardized food dressings and condiment sauces)
that contain small amounts of low-acid food(s) and have a
resultant finished equilibrium pH that does not significantly
differ from that of the predominant acid or acid food,
and foods that are stored, distributed, and retailed under
refrigeration are excluded from the coverage of this part " (5).
The following examples of acidified foods are provided in
the rule: " beans, cucumbers, cabbage, artichokes, cauliflower,
puddings, peppers, tropical fruits, and fish, singly or in any
January/February Food Protection Trends
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Food Protection Trends - January/February 2022

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