Freeze‐drying is a well‐known dehydration method widely used to preserve microorganisms. In order to produce freeze‐dried yeast starter culture for the brewing purpose of African sorghum beer, we tested protective agents (sucrose, glucose, glycerol) in combination with support materials (millet, maize, sorghum, and cassava flours) at 1:1 ratio (v/v). The yeast strains Saccharomyces cerevisiae F 12–7 and Candida tropicalis C 0–7 previously isolated from sorghum beer were used in a mixed culture at a ratio of 2:1 (C. tropicalis/S. cerevisiae). After the freeze‐drying, the residual water contents were between 0.78 –2.27%, 0.55 –4.09%, and 0.40–2.61%, respectively, with sucrose, glucose and glycerol. The dried yeasts viabilities were between 4.0% and 10.6%. Among the protective agents used, sucrose was found to be the best protectant giving cell viabilities of 8.4–10.6%. Considering the support materials, millet flour was the best support after drying. When the freeze‐dried yeast powders were stored at 4°C and room temperature (25–28°C) for up to 3 months, the survival rates were the highest with cassava flour as the support material.

The fungi associated with the spoilage of pineapple fruits in Abidjan market were studied. Spoilt and healthy pineapple fruits were used in the study with potatoes dextrose agar as the culture medium while the pour plate technique was employed in the fungal isolation. Restriction digestion analysis of the ITS products was tested as a simple method to identify isolates of filamentous fungi on pineapple fruits. Endonucleases SduI, HinfI, HhaI, NlaIII, HaeIII, RsaI were used. The studied 10 species generated different composite profiles. Different fungal strains responsible for the spoilage were isolated from various markets in Abidjan and identified by this method. Aspergillus was the genus the most frequently isolated, while the genus Penicillium was absent. Aspergillus aculeatus was the most isolated species of Aspergillus. The Candida sp., Rhizopus oryzae and Geotrichum candidum were also isolated. To the best of our knowledge, is the first report of the presence of Neurospora tetrasperma on pineapple. This technique is a rapid and reliable method appropriate for routine identification of fungi. This can be used to screen large numbers of isolates from various environments in a short time. This is the first exhaustive study of fungal diversity at species level in pineapple fruits.

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