MAP quality control

RESIDUAL OXYGEN

When packaging, it is important to keep the proportion of O2 in the packs as low as possible. A low oxygen content delays the growth of bacteria, and along with CO2 it helps to prolong the shelf life of the products.

If the O2 content in the packs is too high, the product may become discoloured. This applies particularly to raw meat.An excessive oxygen content also promotes rancidity, which again reduces the quality and shelf life of the product.

There are special instruments which measure this value. The frequency with which the measurements are taken is decided by each individual company and is based on an assessment of factors such as the amounts that are packaged.

Table showing the development of discoloration on excessive residual oxygen

Amount of residual oxygen	Development of discoloration
Packages with less than 1% residual oxygen	A good red colour
Packages with values from 1-1.5% residual oxygen	The meat is discoloured. but the process takes place slowly
Packages with values from 1.5-2% residual oxygen	The meat is discoloured, the process taking place more quickly than for packages with 1-1.5% residual oxygen