Determination of the water content of foods : III The direct determination of total solids in liquid saccharine food products and in meat-curing brines, according to josse-buyze

The filter-paper technique of Josse for determination of total solids in liquid food products poor in biocolloids, as recently modified by Buyze, gives results of excellent consistency, when applied to synthetic mixtures and to fruit syrups of well-known composition. The time required for reaching constant weight of the residue varies from 2–5 (average 3½ h) at 100° C

Media for Enterobacteriaceae

The ‘rag-bag character of ‘coli-aerogenes’ bacteria used originally as markers for process failure has prompted their substitution by the taxonomically accurately delineated group of Enterobacteriaceae. Media previously used for the detection or enumeration of the coli-aerogenes group can be adapted to monitoring Enterobacteriaceae simply by replacing lactose by glucose. Test strains including fastidious as well as more robust Enterobacteriaceae are used for the evaluation of media considered appropriate. They should be recovered within 0.5 log10 of cfu-numbers obtained on non-selective media whereas sporeformers and cocci should lead to less than 5 log10 cycles of the recovery on or in control media

The destruction of Salmonella bacteria in refrigerated liquid whole egg with gamma radiation

Thermal pasteurization being a borderline process, it was attempted to use ionizing radiation for rendering whole egg, intended for preservation by other methods than freezing, free from Salmonelleae. Initial densities of about 107/ml of S. typhimurium and S. senftenberg were used. Irradiation was carried out with a ca. 1500 c Co60-source, the inoculated whole egg being packed in lacquered tins and kept at ca. 1°C during this treatment. Six decimal reductions of the Salmonella-species tested were obtained at dosages of 2 × 105 rad, nine reductions at slightly over 5 × 105 rad. No effect of the use of specific recovery media or pre-treatments on the apparent dose value required for obtaining these reductions could be established. The odour of the whole egg and its functional properties appeared to have been impaired at dosages of 104 rad, while the colour suffered from ca. 2 × 105 rad. Therefore, the radiation pasteurization of liquid whole egg at ca. 1°c cannot be considered a promising process

Mould spoilage of cereals during transportation by sea from Latin America to Europe mechanisms, impact and management

Safe water contents of consignments of cereals to be shipped overseas can be calculated from the relation between mould-free storage time and storage conditions (temperature of the environment, aw of the cereal), corrected for heterogeneity of water distribution, content of damaged kernels and degree of infestation by insects. The validity of this model was substantiated by the inspection of shipments and theoretical data from the literature. This predictive model can usefully be substituted for previously used, ill-defined criteria like average or any portion's water content and should prompt the trade to sell consignments of cereals on the basis of dry substance

Media for Campylobacter jejuni and other campylobacters

Despite their recent elaboration and the many variations in antibiotic combinations designed to attain selectivity, highly selective liquid and solid culture media for Campylobacter jejuni have proved satisfactory provided they are incubated at about 42°C and in a microaerophilic atmosphere such as a candle jar. Two reservations apply: (i) cephalothin should not be used when C. fetus is to be isolated as well as C. jejuni; and (ii) typical colonies obtained on selective isolation media should always be checked for failure to grow on blood agar slants in air

Introduction and prospective

The activities of the Working Party on Culture Media (WPCM) of the International Union of Microbiological Societies (IUMS) since 1978 are reviewed. The assignments at hand include (1) drawing up a list of media used on a large scale and therefore qualifying for a pharmacopoeia-type monograph, making serious attempts to eliminate bias resulting from parochial preference; (2) requirements for the functioning of these media, i.e. productivity and selectivity, with regard to the type of specimen being examined