Food aid projections for the decade of the 1990s
Report of an ad hoc panel meeting, October 1988. Board of Science and Technology for International Development, National Research Council, National Academy Press, 2101 Constitution Avenue NW, Washington, D.C., USA 20418.
Major discrepancies have been observed in estimates of the number of malnourished people according to FAO, the World Bank and other organizations. It is agreed, however, that their relative number (as a percentage of the total population) decreased from 35 percent in 1950 to 17 percent in 1988, although this decline has slowed in recent years and the absolute number of malnourished people continues to increase.
Increases in food aid, which doubled between the late 1960s and the latter half of the 1980s, corroborate this fact. While similar levels of aid are expected to be maintained, the magnitude of the problem in the future remains uncertain.
This publication is based on the report of a workshop which was staged to make a systematic revision of the various methodologies used by FAO, the World Bank, the International Food Policy Research Institute and other institutions to project food aid needs and compare the results of these projections.
Food aid needs are defined by certain institutions as the amount necessary for achieving food price stabilization. For others, food aid should meet nutritional requirements (which implies an improvement in the nutrition situation). If the first definition applies, food aid needs from the present day up to the year 2000 can be expected to double. If the second one applies, they will quadruple.
All estimates are based on market projections from which future food aid needs are deduced either directly or indirectly. Food aid projections are valid in the short term but not in the long term, since protracted food aid can affect domestic food production.
The publication also reviews how the projection of food aid needs may be affected by different factors such as demographic patterns, the future impact of the "green revolution" and climatic changes which influence the food chain.
Food aid projections for the decade of the 1990s is a well-documented book and should be interesting reading for specialists.
P. Baron
Senior Officer, Food Aid Support Group, FAO
Food contamination from environmental sources
J.O. Nriagu and M.S. Simmons. Wiley series on Advances in Environmental Science and Technology, Volume 23. Series editor, J.O. Nriagu, USA 1990.
Food is most essential for human life and should be available in sufficient quantities. It should also be nutritious and safe for consumption. Foods can become contaminated for many reasons at any point during production, processing, storage, distribution or consumption. While some contaminants were identified long ago, others, and in particular environmental pollutants such as mycotoxins, industrial chemicals, radionuclides and pesticide residues, have only recently claimed attention. Environmental contaminants in foods are causing increased international concern regarding their impact on public health and, moreover, the major economic implications they have for the food trade at national and international levels.
Wiley's series on Advances in Environmental Science and Technology constitutes a scientific chronicle of modern environmental concerns. Volume 23, Food contamination from environmental sources, presents a critical assessment of certain toxic contaminants in the food chain such as agricultural chemicals, cadmium, lead, arsenic, polychlorinated biphenyls, organochlorides, mycotoxins and trace elements in seafoods.
Each chapter provides an in-depth perspective of these environmental contaminants in foods, including their sources and transfer to human food; methods for their determination in the diet; their distribution and levels of contamination in various foods; their bio-availability; and so on.
Food contamination from environmental sources provides a comprehensive overview of the recent considerations dedicated to environmental contamination of foods, considerations that are of general concern in the scientific world today.
The appendix, presenting FAO work in food contamination, especially in developing countries, is a notable effort to highlight the need for international cooperation in this sensitive field.
Food contamination from environmental sources is a fundamental reference for those involved in toxicology, the environmental sciences, public health and food science activities and studies in general.
Colette Canet
Nutrition Officer (Food Contamination Monitoring), Food Quality and Consumer Protection Group, FAO
Rancidity in foods, 2nd ed.
J.C. Alien and R.J. Hamilton, eds. 1989. London and New York, Elsevier Applied Science. 256 pp., 59 tables, 47 illustrations. Price £ 37.00. ISBN 1-85166-327-4.
This is the second edition of a book arising from a Symposium on Rancidity, held in 1982 by the Society of the Chemical Industry. The new edition is updated and expanded with new chapters on the prevention of rancidity from the viewpoint of producers and refiners of oils and fats, and on rancidity in meat and meat products. It is practical in its approach and most chapters are accompanied by a comprehensive reading list which indicates more exhaustive descriptions of the phenomenon of rancidity, its measurement and control.
Hamilton's opening chapter on the chemistry of rancidity in foods is an excellent and readable summary of the complex reactions leading to oxidative and hydrolytic rancidity. One of the strengths of the book is the chapter on measurement of rancidity, which is comprehensively referenced and describes the various techniques used to estimate the degree of rancidity - both hydrolytic and oxidative - and the degree of resistance to oxidative rancidity. The bases of each of the available tests are well described and the author is careful to draw attention to the empirical nature of all of the techniques in common use; the consequent need to pay particular attention to detail when practising the methods; and the difficulty in interpreting the results, especially when different methods are used in different laboratories. This chapter is supported by another on the evaluation of oxidative rancidity techniques. Useful supporting information on the measurement of rancidity is found in a later chapter on natural antioxidants. The chapter on rancidity in cereal products contains three appendixes containing methods specific for use in these products.
Three chapters are devoted to the prevention of rancidity: «Practical measures to minimize rancidity in processing and storage» discusses design and operational factors which can be employed and offers a number of practical solutions for avoiding the abuse of fats and oils during storage, transport and processing; «The use of antioxidants» describes the functions of these substances, how and why they extend the shelf-life of good quality fats and oils, and the benefits and practical limitations of using them - discussing the steam volatility of BHT (butylated hydroxytoluene) and why this is a problem in frying oils, for example. This chapter also discusses the permitted rates for use of antioxidants in fats and oils in the United Kingdom, the EEC and the United States. Unfortunately, it overlooks the work of the Joint FAO/WHO Expert Committee on Food Additives, which has studied the safety in use of these compounds, and also the levels of use recommended by the FAO/WHO Codex Alimentarius Commission. Both bodies generally support the controlled use of antioxidants and measures to ensure consumer protection and facilitate international trade. A very interesting chapter on natural antioxidants outlines the properties of tocopherols and certain spice extracts, including an extract of rosemary leaves. Ascorbic acid and ascorbyl palmitate are only briefly referred to as antioxidants but they prevent the development of oxidative defects other than rancidity. A short reference to literature in this area would have been welcome.
A chapter entitled «Nutritional aspects of rancidity» deals exclusively with the toxicological effects of oxidized fats, lipid peroxides and oxidized sterols. In fact, there is no reference to nutrition in the book's index and this chapter appears under "toxicity". The chapter is well-referenced and draws attention to potential problems arising from the high-temperature cooking of fatty foods or oily fish as well as the exposure of such foods to ionizing radiation.
The second half of the book deals with the problems of rancidity in specific commodities. The reviewer found the chapters dealing with cereal products, dairy products and meats to contain better background information on the chemical and physical processes leading to problems of rancidity than did the chapters on snack foods, creams and desserts, biscuits and confectionery products. These chapters tend to emphasize practical problems and how they are resolved. The role of effective packaging which retards oxidation and yet presents these products in an effective way to the consumer is discussed.
Rancidity in foods will be a useful addition to any collection on specific problems in food technology. The sections on the measurement and interpretation of results as well as those on quality control in the fats, oils and related industries will ensure a wide readership.
Alan W. Randell
Senior Officer, Joint FAO/WHO Food Standards Programme, FAO
Low-calorie products
G.G. Birch and M.G. Lindley, eds. 1988. London and New York, Elsevier Applied Science. 267 pp., 49 tables, 73 illustrations. ISBN 1-85166-1.
This very interesting book appeared before the advent of Food, Nutrition and Agriculture and we have not had the opportunity to review it until now. It reports the proceedings of an industry-university cooperation Symposium, organized under the auspices of Britain's National College of Food Technology (Department of Food Science and Technology), University of Reading, 25 to 26 March 1987. As Is the case with all such collections of symposium papers, the quality of the individual contributions is variable, but the overall quality of this publication is very good and certain papers are, indeed, excellent. Consequently, this is an important book which explores an area of special interest to nutritionists, food technologists, food regulatory authorities, the food industry and the general public. It will be of equal interest to developing countries where national food industries, importers and food control authorities are facing a growing trend toward the use of low-calorie products as markets: become more sophisticated. This book will allow a better understanding of the products available, their composition and their potential use.
For the most part, the technology of low-calorie products is based on the use of food additives to replace one or more of the carbohydrates or fats while still giving the same sensations of taste and texture as the basic food. In some cases this can be done by the simple substitution of sugar with an artificial sweetener. However, where sugar also acts to provide body to the product and protect it from bacteriological growth, the careful use of hydrocolloids such as low-ester pectins combined with appropriate preservatives is the only answer. Similar effects can be achieved in some cases by manipulation of the physical chemical properties of existing food constituents, especially proteins. Low-calorie products spends considerable time examining the most commonly used food additives, although it must be said that this treatment is restricted and the reader should assume that the products described are only given as examples of the wide range of substances available. The non-calorie sweeteners are given the best treatment, with comprehensive papers on Acesulfame K, Aspartame and saccharin. For some reason cyclamates, which have full toxicological clearance from the Joint FAO/WHO Expert Committee on Food Additives (JECFA), are not described.
Carbohydrate derivatives can be used as low-calorie bulking agents to allow the creation of reduced-calorie and low-calorie foods by replacing all or part of the sugars and some of the fats without sacrificing texture, bulk or palatability. These include the two substances given detailed treatment here: Polydextrose and Isomalt. Unfortunately, there is no generic treatment of the use of bulking agents, many of which have been cleared by JECFA for use in foods. Conversely, there is an Interesting but far too brief chapter on low-calorie fat substitutes.
The book contains a series of papers which evaluate the effects that low-calorie food consumption has on those who hope to lose excess weight or maintain their figure. M.G. Tordoff. in an excellent review entitled Saccharin and food intake, suggests that the use of saccharin tends to increase food intake and claims that there are few scientific data to confirm or deny the general belief that non-nutritive and low-calorie sweeteners aid calorie reduction and weight loss. J.E. Blundell and his colleagues from the University of Leeds (United Kingdom) provide further background in regard to other artificial sweeteners. They are concerned that the consumption of artificial sweeteners does not perse perform a weight-reducing or weight-regulating function, possibly because of effects of residual hunger. Two very well-referenced papers describe Nutrient ingestion and body weight regulation and Genetic differences in metabolic rate. Although interesting in themselves, they are slightly out of place in a review of Low-calorie products because they apply to the broader context of excessive calorie intake. The same is true of an excellent description of the Consequences of obesity.
The question of determining the calorific value of low-calorie products is discussed in two papers and the book is rounded-off by a brief analysis of legislation relating to low-calorie products. This concentrates on the situation in the United Kingdom regarding the regulation of food additives. It is unfortunate that the paper does not deal with wider problems, such as those of labelling and claims, and that it is based on local considerations only. Nevertheless, it concludes with the interesting statement that "the use of food additives in the manufacture of low-calorie products can be seen to provide an example of demonstrable consumer benefit... ".
A.W.R.
FAO training in mycotoxins analysis
FAO Food and Nutrition Paper No. 14/10. 1990. Rome, FAO.
For a number of years, FAO has been assisting developing countries in strengthening their capabilities to prevent and control the contamination of food by mycotoxins, particularly aflatoxins. During this time, several international training courses and conferences have been organized. The courses are held on an ad hoc basis, with invited consultants and lecturers providing their own material. However, it was felt that a more uniform approach would be desired, while still retaining a certain degree of flexibility and country specificity, and a core syllabus for a training package was therefore formulated.
The present manual was prepared to provide a training package for national governments of developing countries seeking to improve their mycotoxin prevention and monitoring programmes. It is intended to be used for the training of analysts over a three-week period at national and regional levels. Emphasis has been placed on analyses for aflatoxins in foods and feeds.
Also included is general information on the organization of training courses; mycotoxin problems; practical aspects of sampling; analytical procedures; performance characteristics of the analytical techniques; and quality assurance. Thin layer chromatography and ELISA techniques are the main laboratory procedures described.
C.C.
