PR | EPTD; | IFPRI3; | Journal article

"This is the highly anticipated third edition of a book written by the Working Party on Culture Media of the International Committee on Food Microbiology and Hygiene. It is a handy reference for microbiologists wanting to know which media to use for the detection of various groups of microbes in foods and how to check the performance of the media. | The book is divided into two parts and concentrates on media for water as well as food microbes - selecting those which have been evaluated and shown to function optimally. The first part consists of a series of chapters written by various experts from all over the world, reviewing the media designed to detect the major groups of microbes important in food spoilage, food fermentations and food-borne disease. The history and rationale of the selective agents and indicator systems used, as well as the relative merits of the various media are surveyed by reference to the scientific literature. The second part contains monographs on almost 100 of the media considered most useful. Each monograph, written in the style of a pharmacopoeia, includes: a short section on the history and selective principle of the medium; a method for its preparation from basic ingredients; its appearance and physical properties, including pH; its shelf-life; instructions concerning method of inoculation, incubation and interpretation; the recommended method(s) and a list of test strains suitable for assessing the quality (productivity and selectivity) of the medium and a description of the typical appearance of the target organism"--Publisher decription.

The water footprint assessment framework aims to illustrate the full impact of water consumption in the whole life cycle of a product, from direct water extraction to water pollution. The framework provides a comprehensive indicator for water resources which, if used with care, can provide detailed information about the different impacts of water consumption in order to aid with water stewardship in the agri-food sector. However, the framework suffers from considerable uncertainties caused by discrepancies in the selection of critical limit values, leaching fractions or models and defining the scale of the study. A case study of oat farming in southwestern Finland and two oat products, oat flakes and an oat drink, is used to illustrate difficulties and opportunities in the application of the framework. The water footprint accounting is done with an applied leaching model and watershed specific nutrient limits for Finland in order to show the importance of the selection of critical parameters. Especially the grey water footprint, a measurement of water pollution and serves as an indicator for water quality, is emphasized as a crucial component in the total embedded water of agri-food products. In this study phosphorus was selected as the critical nutrient in the grey water footprint calculations. Moreover, an alternate impact assessment deviated from the one presented in the water footprint manual is suggested to better illustrate the changes in assimilative capacity of the selected water body. The water footprint of oat is, in this study, calculated to be highly variable depending on the chosen watershed, the leaching model or fraction, and the natural and maximum phosphorus concentrations defined. The study shows that the water footprint assessment framework can only become valuable as an indicator if the parameters used are carefully selected, while reliable benchmarking can only follow if the parameters are standardized. If the assumptions and methodology used are clearly defined from the onset of the assessment, the framework can serve as a useful internal indicator to show trends in water use and quality. Finally, the study illustrates the importance of considering diffuse pollution when planning water stewardship in the agri-food sector.

PR | Book chapter | EPTD | IFPRI-4

A molecular dynamics (MD) modeling and simulations approach has been rationally built and developed to study porous food systems constructed with amylose and dextran chains. The findings from our MD studies indicate that the presence of food macromolecules decreases the energetics of the water–water interactions for the nearby water molecules in the pore space, but provides additional water–macromolecule interactions that can significantly outweigh the partial loss of water–water interactions to make the adjacent water molecules strongly bound to the food macromolecules so that the water activity and water removal rate are decreased as dehydration proceeds and, thus, the dehydration energy requirement would be increased. The effects of pore structures are greater in systems with higher densities of food macromolecules, smaller in size pores, and stronger water–macromolecule interactions. Dehydration of food materials can thus be reasonably expected to start from the largest pores and from the middle of the pores, and to have non-uniform water removal rates and non-planar water–vapor interfaces inside individual pores as well as across sections of the food materials. The food porous structures are found to have good pore connectivity for water molecules. As dehydration proceeds, water content and the support from water–water and water–macromolecule interactions both decrease, causing the food porous structures to adopt more compact conformations and their main body to decrease in size. Dehydration in general also reduces pore sizes and the number of pore openings, increases the water–macromolecule interactions, and leads to the reduction of the overall thermal conductivity of the system, so that more energy (heat), longer times, and/or greater temperature gradients are needed in order to further dehydrate the porous materials. Our thermodynamic analysis also shows that the average minimum entropy requirement for food dehydration is greater when the water–macromolecule interactions are stronger and the food macromolecular density is higher. The importance of the physicochemical affinity of food molecules for water and of the compatibility of the resultant porous structures with water configurational structures in determining food properties and food processing through the water–macromolecule interactions, is clearly and fundamentally verified by the results and discussion presented in this work.

Book chapter | EPTD | Non-PR | IFPRI-4