most difficult beverage soils to remove. This
deposit is most effectively removed with
extensive scrubbing and use of a strong
chelating agent and alkaline cleaning com-
pound.
Bottle Washing
When returned, the bottler should exam-
ine the empty bottles. New bottles should
also be inspected at the bottling plant to
detect any obvious contamination. All new
and used bottles should be mechanically
washed immediately before filling with a
washer that applies a heavy spray of caustic
solution, both internally and externally, with
subsequent rinsing. The spray and rinse tem-
perature should be 60 to 70ºC. Chlorination
of the final rinse with up to 0.5-ppm concen-
tration can be incorporated without affect-
ing the flavor of beer. Chlorination is not
necessary unless the water characteristics
dictate this purification technique.
Beer Pasteurization
Most brewers pasteurize their beer to
maintain a stable condition, flavor, and
smoothness. Certain brewers have incorpo-
rated sterile filtration as a substitute for ster-
ilization. If filtration is incorporated, the
filters should be replaced every other week to
reduce the risk of microbes penetrating the
series of filters. In a sanitary operation, ster-
ile filtration can be effective.
Pasteurization during containerizing is
practiced by much of the brewing industry
because it can protect the beer against con-
tamination after packaging. Overheating
during pasteurization, however, can have an
adverse effect on flavor and can cause haze.
Therefore, it is essential to subject the beer
to the minimum time and temperature for
effective microbial destruction. Most of the
brewing industry now has conveyor systems
for a pasteurization cycle of approximately
45 minutes. During pasteurization, the tem-
perature of the beer is gradually raised from
1 or 2ºC to 61ºC up to 63ºC, with subse-
quent cooling to ambient temperature at the
end of the cycle. The moving belt speed can
determine the length of exposure time in the
pasteurization environment. Pasteurization
is known to speed up the reactions that give
oxidation haze, so the effects of an excess of
air may be accentuated with pasteurized
beers. The total air content of packaged
beer should not exceed 1 mL/220 mL of
beer.
Haze may develop in beer. A non-biolog-
ical haze may form from the slow precipita-
tion of products with unstable solubility-a
condition caused or accelerated by oxida-
tion. A biological haze may be caused by
the growth of bacteria or yeasts. A suffi-
cient period in the cold conditioning tank
and fine filtration will minimize the chances
of non-biological haze. The exclusion of air
in the beer container, as well as the selection
of suitable container materials, will also
minimize the chances of non-biological
haze occurrence. Other hazes have been
traced to metallic influences, especially that
of tin. Haze of beer in brightly colored bot-
tles due to bacteria or yeast growth suggests
either imperfect filtration or subsequent
infection. A bacterial or yeast haze can be
attributable to lack of proper sanitation in
the plant or unclean storage containers or
filters.
The application of sanitizing compounds
is referred to “cold pasteurization” (Cars-
berg, 2003). The bacterial count of yeast
added to wort (pitching yeast) can be
reduced by treatment with diluted acids such
as phosphoric, sulfuric, and tartaric. How-
ever, acid treatment can affect yeast cultures
through retarded fermentations.Cleaning of Air Conditioning Units
The following procedure for cleaning air
conditioning units is suggested: