[Preservation of meats in a controlled atmosphere].

Commercializing meat sets problems more particularly connected with its organoleptic and microbiological qualities. As these qualities, resulting from biochemical and microbial effects, develop during the storage, the conditioning must precisely help their controlling. After examining their factors, the Author analyses the processes of conditioning which he classifies in three categories according to the techniques used and the desired finality (need to store at -1 degree C + 3 degrees C). 1. Conditioning under a steam-proof and gas pervious (O2-CO2) film. Composition of the internal atmosphere permanently close to that of the normal atmosphere. No change in the bright red colouring at the surface (oxymyoglobin). Microbial growth slowed down by refrigeration. Limited storage (a few days). Comminuted meat trade. 2. Conditioning under a totally steam--and gas--proof film. Internal atmospheric air under reduced volume and pressure ("vacuum-packed" meats). Internal changes during the storage: reduced rate O2; increased rate CO2 (cellular and microbial respirations). Surface becoming darker (absence of oxymyoglobin). Growth of the germs arrested (pathogenic and spoilage). However development of microaerophilic and acidophilic germs (in particular the lactic B.). Storage possibly extended to 8 weeks. Re-apparition of the red colour after oxygenation (opened package). Wholesale meat trade. 3. Conditioning under a film with properties close to that of (2 degrees). Initial constitution of an internal "artificial" atmosphere increased in O2 and CO2 (gas injection). No change in the bright red colouring (oxymyoglobin). Growth of the germs arrested (pathogenic and spoilage). Selection of an acidophilic aerobic flora including lactic B. and microbacterium. Storage until 12-15 days. Comminuted meat trade.