Modified Atmosphere Packaging of Raw Offal

Extending the shelf-life of raw offal products

Raw offal products include Liver, kidney, heart, sweetbreads, tongue, tripe, oxtail, neck, giblets, foie gras, feet, or trotters.

The two main spoilage mechanisms affecting the shelf-life of raw offal products are microbial growth and oxidation of the red pigment to its brown oxidised form. For this reason, high concentrations of O2 are necessary for the MAP Modified Atmosphere Packaging of raw offal in order to maintain the desirable red colour for a longer period.

Aerobic spoilage bacteria, such as Pseudomonas species, which are normally predominant on raw offal are inhibited by CO2. So in order to retain red colour while inhibiting micro-organisms, a gas mixture containing 20% CO2 and 80% O2 is recommended for extending the chilled shelf-life of raw offal from 2–6 days to 4–8 days. A gas/product ratio of 2:1 is recommended.

Many types of raw offal,  particularly liver, kidney, brain, foie gras, giblets and sweetbreads, tend to suffer from excessive drip, especially in the presence of CO2, and thus only a maximum of 20% CO2 should be used. The potential problem of excessive drip can be controlled by using the retail three-web pack.

The maintenance of recommended chilled temperatures and good hygiene and handling throughout the butchery, MAP, distribution and retail chain is also of vital importance in ensuring the safety and extended shelf-life of raw offal products. Raw offal provides an ideal medium for the growth of a wide range of spoilage and food poisoning micro-organisms.
It should be noted that raw offal products are subsequently cooked before consumption and thorough heating is sufficient to kill the vegetative cells of food poisoning bacteria. Consequently, the risk of food poisoning is greatly minimised by proper cooking.

General Information for Modified Atmosphere Packaging of Raw Offal