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-Introduction. The aim of our research was to test various techniques of packaging for dates stuffed with almond paste and Deglet Nour natural dates, products of national economic interest in Tunisia. Effects of storage temperatures and packaging types were studied from yeast and mold evolution and water content of stored products. Materials and methods. Natural or stuffed date storage was evaluated by using four packaging types: setting the products in an amorphous polyethylene terephthalate small wrapping (APET) with simple sealing; vacuum packaging or modified atmosphere packaging with injection of two different amounts of a gas mixture (20% CO 2 and 80% N 2 ). The sample storage was carried out at three temperatures [(20, 30 and 40) °C] to cause and accelerate the ageing of the dates and, thus, evaluate their shelf life. Results and discussion. Vacuum and modified atmosphere packaging made it possible to decrease the date dehydration during storage. While being based on the product water content, the stuffed date packaging stored under 20 °C in small APET wrappings and having received a 10% gas mixture injection made it possible to obtain a shelf life equal to 6.6 months compared with 4.2 months observed in the case of a simple sealing of these wrappings. For natural dates stored under 20 °C, the application of a partial vacuum packaging increased the shelf life from 3.8 months, obtained for a simple sealing, to 9 months. Conclusion. The use of specific packaging techniques would thus make it possible to preserve for longer the initial stored date quality. The vacuum packaging of natural dates is the most adapted to better protection of the product against yeast and mold proliferation and against dehydration. For stuffed dates, modified atmosphere packaging with a 10% gas mixture injection proved to be the best for preserving the initial quality of the product during its storage.Tunisia / Phoenix dactylifera / packaging / controlled atmosphere storage / vacuum packaging / keeping quality / microorganisms Effet de différents conditionnements sous vide ou sous atmosphère modifiée sur la conservation de dattes Deglet Nour en Tunisie.Résumé -Introduction. L'objectif de nos recherches a été de tester différentes techniques de conditionnement de dattes Deglet Nour naturelles et de dattes fourrées à la pâte d'amande, produits d'intérêt économique national en Tunisie. Les effets de la température d'entreposage et du type de conditionnement ont été étudiés par rapport à l'évolution des levures et moisissures et de la teneur en eau des produits stockés. Matériel et méthodes. La conservation des dattes (naturelles ou fourrées) stockées a été évaluée en utilisant quatre modes de conditionnement : mise en barquettes de polyéthylène téréphtalate amorphe (APET) avec simple scellage ; conditionnement sous vide ou emballage sous atmosphère modifiée avec injection de deux différentes doses d'un mélange gazeux (20 % CO 2 et 80 % N 2 ). L'entreposage des échantillons a été effectué à trois températures [(20, 30 et 40)°...

The survival rates of two freeze-dried strains, Lactococcus lactis var diacetylactis and Lactococcus lactis var lactis, were evaluated using the Accelerated Shelf Life Testing (ASLT) method. The strains were initially isolated from a brand of a Tunisian fermented milk product. Lactococcus cell survival observed at higher temperatures was used to extrapolate to shelf life at a lower storage temperature of 4°C. The apparent kinetics of the survival rate loss were estimated and the effect of storage temperature was quanti®ed by determining the inactivation energies for various samples. The work has shown an overall higher survival rate of the strain Lactococcus lactis var diacetylactis. An average half-life of a strain maintained at 25°C was equal to about 7 days as compared with about 43 days at 4°C. The addition of lyoprotectants such glycerol, saccharose and calcium carbonate to the drying medium, improved the survival of such bacteria.