Integrierte Vermeidung und Verminderung der Umweltverschmutzung

2.1.8.2.2 Field of application
Chapter 2
Gas flushing is mainly used for meat and meat products. It is also used for bakery products.
Storage under gas is, above all, applied to white wines, rosés and red primeurs.
2.1.8.2.3 Description of techniques, methods and equipment
In gas flushing, the gas mixtures used will vary depending on whether the meat to be protected
is fresh or cured. The desirable bright red colour of fresh meat can be prolonged by storage in an
atmosphere with some oxygen, whereas the purple-red colour of uncooked cured meat and the
pink colour of cooked cured meat is preserved better in an atmosphere completely free of
oxygen. In all types of meat or meat products, gas mixtures are used which also contain carbon
dioxide (CO2). This inhibits bacterial growth on the meat and marginally extends the shelf-life.
Normal air contains 78 % nitrogen, 21 % oxygen, and less than 1 % CO2. In comparison, typical
gas mixes for use with meats and meat products are shown in Table 2.5.
Nitrogen Oxygen CO2
Fresh meat 20 % 60 % 20 %
Cured meats 80 % 0 % 20 %
Table 2.5: Typical gas mix composition for gas flushing
[1, CIAA, 2002]
Solid CO2, usually in pellet form, can be added to meat during size reduction. This has the effect
of rapidly reducing the temperature of the mixture and creating a blanket of inert gas over the
surface of the meat, thereby enhancing the colour retention. A temporary increase in the CO2
content of the air surrounding the equipment will occur, but this dissipates rapidly.
Solid or liquid nitrogen or CO2 is sometimes used to partially freeze meats prior to slicing. This
involves passing the pieces of meat to be sliced through a tunnel in which they are sprayed with
the liquefied gas to reduce their temperature to about -8 °C. In such instances, extractor fans are
located near the ends of the tunnel to expel the surplus gas to the air. No adverse effects have
been reported.
Storage under gas consists of putting a gas, which can be either food quality nitrogen or a
nitrogen/CO2 mixture, in a tank under very slight overpressure of 0.1 to 0.2 bar. Nitrogen is
used in a compressed state in steel containers. CO2 is used in a liquefied form under pressure.
2.1.9 Utility processes (U)
2.1.9.1 Cleaning and disinfection (U.1)
2.1.9.1.1 Objective
Processing equipment and production installations are cleaned and disinfected periodically to
comply with legal hygiene requirements. The frequency can vary considerably depending on the
products and the processes. The aim of cleaning and disinfection is to remove product remnants,
other contaminants and micro-organisms.
2.1.9.1.2 Field of application
The whole FDM sector.
RHC/EIPPCB/FDM_BREF_FINAL January 2006 51