IBP NEWS
ULTIMATELY HYGIENIC
REDUCED BIOFILM FORMATION IN TUNNEL PASTEURISERS
THANKS TO ANOLYTE
The Goal: Reducing
Germs in the Product
Without Altering its
Flavour The process water in the tunnel
pasteuriser’s heating and cooling zones
requires special attention and treatment
with regard to hygiene and biofilm
formation: through innovative and
contemporary gentle water disinfection,
Innowatech sets new hygiene standards.

Anolyte as hygienic solution in the
tunnel pasteuriser: this pH-neutral
disinfectant inhibits high proliferation
rates of germs in the process water even
at extremely low concentrations and
thus also prevents biofilm formation.

The active ingredient, produced in-situ
from sodium chloride and water
through membrane cell electrolysis,
replaces aggressive, off-gassing and
expensive disinfectants.

Pasteurisation is the safest way to
preserve food and drinks in jars, cans
or bottles. That’s what the textbooks
say. And brewers and maltsters know
that this rule applies all the more
when beverages contain fermentable
substances. Large breweries with high
output, which produce for the European
and global markets, in particular, rely
on the tunnel pasteuriser.

Pasteurising beer can significantly
extend its shelf life and thus facilitate
longer transport routes to the retailer.

14 A conveyor belt feeds
the filled and sealed
bottles at an inlet
temperature of 8 to 10
°C into the pasteuriser.

The pasteuriser
features various
temperature zones in
which the bottles and
the product they contain are gradually
heated (40, 50, 60, 75°C). To this end, the
bottles are constantly sprayed with hot
water distributed by nozzles and heated
until the pasteurisation temperature of
ca. 60 to 75°C has been reached.

The bottles stay in this zone for 10
to 30 minutes.

Pasteurisation reduces the
microorganism count in beer, other
beverages and food, and thus extends
the products’ shelf life. When it comes
to taste, odour, turbidity and colour, it
is necessary to gently heat the products
to preserve high quality. This is why
re-cooling takes place across several
temperature zones in order to maintain
high beverage quality and avoid the risk
of glass breakage.

The process heat, which is usually
generated by hot steam, is derived from
the water by a plate heat exchanger
during re-cooling and fed back into the
heating process.

This facilitates a high level of heat
recovery. A tunnel pasteuriser is thus a
seemingly simple, albeit a highly
complex machine. Apart from beer, the
process is also perfect for fruit juices,
carbonated beverages and canned food.

The Challenge of Microbiology
In a brewery’s bottling hall, a tunnel
pasteuriser takes up a lot of space and
is striking just by this. Maintaining
microbiologically flawless water
quality in the pasteuriser`s heating
and cooling zones constitutes a major
challenge for its owner. Various germs
will find ideal habitat conditions in the
temperature zones ranging from 25 to
55°C. In addition to warmth and water,
also sufficient nutrients, introduced
through product residues on the
bottles or through glass splinters, are
available. However, nutrients contained
in the beverages and foods are not only
tasty for humans, but also facilitate
rapid, sometimes even unrestrained,
proliferation of microorganisms. As a
result, more and more biofilm is formed
on the constantly wet inner surfaces of
the pasteuriser.

Especially where the biofilm cannot
be mechanically removed by spray
nozzles, a slimy layer forms over time.

Due to the warmth, it may virtually
cake on the surface and make cleaning
significantly more difficult.

Chemical Treatment with
Biocides and Inhibitors
To counteract the contamination, the
process water is treated with various,
usually organic, biocides. The process
water in the pasteuriser is also
treated with chlorine dioxide. Since
almost all biocides have a corrosive
effect, corrosion inhibitors as well as
– depending on the water hardness –
hardness stabilizers need to be added
to the water.

Organic biocides are supplied
in concentrated form in canisters,
barrels and containers, are often very
expensive and usually only effective in
high concentrations. They are classified
as hazardous substances that make
INTERNATIONAL BOTTLER & PACKER | JUNE 2025