5
Processing Techniques Suitable For Weaning Foods

PROCESSING

Various food processing techniques and additives have the potential to enhance the nutrient bioavailability, nutrient density, food safety, storage stability, palatability, and convenience of supplemental foods suitable for weaning mixtures or to promote nutrition repletion following diarrheal episodes. Some of these are applicable for use at home, while others require the equipment and skills available in a small-or medium-scale food factory (Bressani et al., 1984).

Processing Techniques
Roasting

Roasting describes a process that dry cooks a cereal, legume, or oil seed. The resulting dry ground products can be mixed with sugar and oil and moistened to form a ball that can be fed by hand to an infant or child. Because of the limited ability of roasted products to absorb water, the nutrient density is high. High processing temperatures produce a pleasant toasted flavor that improves palatability and inactivates enzymes and antinutritional factors but also denatures heat-labile vitamins.

Roasting can be accomplished by shaking the grains in a heated pan or by immersing and agitating them in hot salt or sand. Large-scale roasting equipment with improved thermal efficiency that requires only a moderate level of skill to operate is available. Roasting loosens the seed coats, making them easy to remove before the product is ground. Although roasting is one



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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation 5 Processing Techniques Suitable For Weaning Foods PROCESSING Various food processing techniques and additives have the potential to enhance the nutrient bioavailability, nutrient density, food safety, storage stability, palatability, and convenience of supplemental foods suitable for weaning mixtures or to promote nutrition repletion following diarrheal episodes. Some of these are applicable for use at home, while others require the equipment and skills available in a small-or medium-scale food factory (Bressani et al., 1984). Processing Techniques Roasting Roasting describes a process that dry cooks a cereal, legume, or oil seed. The resulting dry ground products can be mixed with sugar and oil and moistened to form a ball that can be fed by hand to an infant or child. Because of the limited ability of roasted products to absorb water, the nutrient density is high. High processing temperatures produce a pleasant toasted flavor that improves palatability and inactivates enzymes and antinutritional factors but also denatures heat-labile vitamins. Roasting can be accomplished by shaking the grains in a heated pan or by immersing and agitating them in hot salt or sand. Large-scale roasting equipment with improved thermal efficiency that requires only a moderate level of skill to operate is available. Roasting loosens the seed coats, making them easy to remove before the product is ground. Although roasting is one

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation of the least expensive cooking processes, it is limited to whole gains and products with uniform piece sizes. Roasting dries grains and destroys much of the surface microflora, thus increasing the shelf life if the product is protected from moisture and insects. Germination Soaked whole grams can be sprouted prior to cooking to increase vitamin levels, reduce the molecular weight of the carbohydrates that are present, and increase the availability of essential amino acids and relative nutritional value of the food (Wang and Fields, 1979). The amylases, released during germination hydrolyze starch to shorter-chain carbohydrates and sugars, facilitating digestibility and reducing viscosity at elevated concentrations to increase the caloric density of foods (Mosha and Svanberg, 1983). Once sprouted, grains have to be dried if they are to remain stable. Heating during or following drying increases flavor and acceptability. Milling Milling, a spectrum of processes, cleans and separates the components of grains (germ, bran, endosperm) and reduces their size. Mining has the beneficial effect of lowering fiber and bulk but it is at the expense of a lowered vitamin and mineral content in the remaining flour. Cleaning steps associated with milling can remove insect and microbiological contamination of raw materials. The mined product, however, is more susceptible to insect damage if it is not protected in packaging that is puncture resistant and resealable Bacteriological growth is not a concern in mined products as long as they have less than a 15 percent moisture content. Milling lowers the phytates present in the bran of many cereal grams and legumes that interfere with the absorption of starch, calcium, minerals, and trace elements. Tannins, which are present in the seed coats of many pigmented cereals, can inhibit the digestion of protein and starch if they are not removed during milling. Simple mills can replace the labor-intensive and time-consuming pounding, grinding, and handwinnowing techniques that are commonly used. Mills consisting of stone or metal grinding parts and blowers can be manufactured locally. Milling by itself does not produce a supplementary food. Instead, mined ingredients are more suitable and convenient for formulating supplemental foods. Milled flours cooked with water form thick gruels with low nutrient

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation density and protein content. Beans, legumes, lentils, oil, and sugar can be added to reduce these shortcomings. Large multistep mills increase the efficiency of separation and size reduction. These mills can produce fine flour, but require imported equipment and extensive technical skill for operation and maintenance. Large flour mills usually include a fortification step to replace the vitamins and minerals that are lost during the milling or bleaching process. Baking Baking is used to produce nutritionally dense biscuits containing fat, sugar, and vegetable and animal proteins. Biscuits can be crumbled, and water or milk can be added to make a gruel. Older children eat biscuits directly as a ready-to-eat supplementary food. Individual biscuits provide a degree of portion control and can be very acceptable to children. Baked products are quite digestible and can be fortified to increase the levels of vitamins, minerals, and protein. Biscuits baked at high temperatures are dry and can be stored for long periods of time. To increase the shelf life, packaging is required to reduce insect infestation and moisture uptake. Baked products normally require expensive refined ingredients such as shortening (off), flour, leavening, and sugar; this increases the cost and may limit their production. Cooking Cereal, legume, and oil seed based products are typically prepared by boiling in 70–90 percent water to completely cook and gelatinize the starch to form a thick paste. The gruels have a low nutrient density unless amylase (sprouted grains) is used to hydrolyze some of the starch to reduce the viscosity at higher solids concentrations. The use of ground beans instead of whole beans added directly to boiling water can reduce cooking time by a factor of 10 (Nelson et al., 1978). Cooking processes affect digestibility in a variety of ways. When heated, the starch granules readily permit water absorption, a process known as gelatinization (Olkku and Rha, 1978). Raw starch is resistant to enzymatic hydrolysis (Jenkins et al., 1986) and digestion before gelatinization occurs. However, the cooking of sorghum in excess water decreases rather than increases digestibility. There are several factors present in some foods that also decrease the digestibility and/or absorption of specific nutrients that are denatured by

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation heat during cooking. For example, protein digestibility is reduced by the protease inhibitors present in legumes (Aykroyd and Doughty, 1964) unless the inhibitors are inactivated by heating. The cooking or reheating of foods can destroy vegetative forms of enteropathogens. The temperature necessary depends on the time of exposure, with only a short interval (less than I minute beating temperature) at greater than 75°C are required. Even at these temperatures, however, heat-resistant spores survive. This is of concern when food is held between the time of cooking and serving. Foods held at temperatures between 20 and 50°C allow bacteria to multiply rapidly. Products cooked with high levels of moisture must be either sterilized in a package or dried if they are to remain stable for any extended period of time. Packaging and sterilization are expensive. Moreover, once the sterile package is opened, the product becomes very susceptible to contamination and spoilage. Both heat and radiation can sterilize, but radiation is unlikely to have applicability in developing countries. Drying Water must be available for spore germination, microbial growth, and toxin production. Drying and the addition of solutes, such as NaCl or sucrose, to the food depresses the water activity (aw) according to the nature of the solute. Water activity is defined as the ratio of the water vapor pressure of the food to that of pure water. The minimum aw for multiplication varies with the microorganism (with bacteria being most sensitive) and is affected by other food conditions, such as temperature or pH. Fresh foods have an aw above 0.98 and are very susceptible to spoilage and multiplication of enteropathogens. Most bacteria do not multiply at an aw lower than 0.9, but some may grow in foods with an aw as low as 0.75 (saturated NaCl). Values this low, however, are attainable only for dried foods, which can be stored for extended periods of time. Drying is an effective preservation technique, although it is relatively inefficient and expensive because of the large quantities of heat required. Thermal efficiency increases with increasing drying temperature and dryer design improvements, but these enhancements require greater operator skill to minimize product damage. Solar drying has been suggested as a low-cost alternative, but it is not suited to drying pastes. Long drying times associated with solar drying can also lead to product deterioration as a result of bacterial growth before drying is complete. Cereal paste drying is commonly done on the surface of hot drums or by spraying the paste into heated air. The resulting dry, precooked products

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation form smooth gruels when they are reconstituted with water. Supplementation with non-fat dried milk or soy protein and vitamin-mineral mixtures improves the nutritional quality. Proper packaging is necessary to protect the product from insects and moisture, but it is costly bemuse of law product density. Extrusion Extruded products are formulated from mixtures of cereals, legumes, and oil seeds and are completely precooked for easy reconstitution and use. They can be fortified with vitamin and minerals (Harper and Jansen, 1985). The process has been used successfully to produce nutritious foods that have been distributed in dry packaged form through both commercial and governmental programs. Extrusion heat processes dry food ingredients by friction between the food and a high-speed screw. Low-cost extruders, which process foods at moistures of less than 20 percent, have the lowest capital and operating costs and can produce fortified, packaged, stable food products for an additional cost of 30–50 percent of the cost of the raw ingredients. Mechanical disruption of the cell walls and starch of plant products occurs during extrusion cooking, facilitating digestion and absorption. This mechanical breakdown of starches reduces the viscosity of gruels made from extruded cereals to enhance their caloric density. The high-temperature heat treatment effectively pasteurizes the product. Six-month storage requires packaging to provide resistance to moisture and insects. Fermentation A variety of fermentation processes have been used with cereals to increase digestibility, palatability, and shelf life. Some of these products have served as weaning foods (Steinkraus et al., 1983). These processes normally begin by soaking the whole grain for 24–72 hours. Wet grinding follows to remove some of the hull and gem. Fermentation at 30–50 percent moisture requires another 24–72 hours at approximately 30°C, using a mixed culture of acid-forming bacteria. Before consumption, water is added to give a 7–10 percent solids concentration, and the Mixture is brought to a boil to produce a gruel. These foods are most common in Africa, but similar processes are used in most countries. Control of temperature, moisture, and type of inoculum alters the pH and flavor of the finished product. The final pH ranges between 3.4 and 3.8

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation because of the fermentation of sugars to lactic, acetic, and other short-chain acids. Since most bacteria grow best at about pH 7.0 and few grow at lower than pH 4, the lowered pH inhibits bacterial growth and extends the shelf life to approximately one day. Fermentation produces a strong acidic flavor, increases protein digestibility, and relative nutritional value. Fermentation can also reduce cyanide toxicity in cassava and sorghum, trypsin inhibitors in soybeans, and the antinutritional character of phytate and tannins. A significant disadvantage of the fermentation process is the lengthy preparation time required. Further, the products have a low caloric density and low protein quantity and quality. These deficiencies can be overcome by hydrolysis of the starch by enzymes from sprouted grains and the addition of vegetable protein sources such as lentils, legumes, or oil seeds before fermentation. Shelf-stable fermented products require drying, which significantly increases complexity and cost, but it adds to the convenience and the ability to expand distribution. Other Fermentations Yogurt and souring of milk are other examples of beneficial acidic fermentations which extend the shelf life and the utility of milk products as supplemental foods. Such fermentation also reduces the level of lactose in the finished product, when lactose intolerance is an important factor. Acidification of milk with lactic acid and lactobacilli was studied in The Gambia and was found to inhibit bacterial growth only to a slight degree, but E. coli counts in acidified or nonacidified milk samples reached similar high levels after 4–8 hours (Barrell and Rowland, 1980). Fermenting soy with fungi produces a variety of traditional foods such as tofu, tempeh, and miso. Acidification of soybeans, either by fermentation or the addition of lactic acid, prevented growth of B. cereus in the production of tempeh and other fermented foods (Nout et al., 1987). These products have higher concentrations of protein but often use salt to control the microflora in the fermentation. This characteristic, however, diminishes the product's value as a supplemental food for rehabilitation of children with diarrhea. Food Additives Natural inhibitors of microbial growth, such as carbonyl, sulfur, or nitrogenous compounds; fatty acids; and other antimicrobial agents can be

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation found in various foods. Their potential role as additives in controlling pathogens is poorly understood, and their potential toxic effects are unknown. No fully suitable food preservative is currently available. In most cases it is preferable to rely on more than one factor to inhibit microbial growth, and often these combined factors have additive or even synergistic effects (Genigeorgis, 1981). It is possible that some combination of factors, for example, pH, the presence of sodium chloride or some other solute (affecting the aw), and temperature may have an inhibiting effect for up to several hours. Except possibly for low-pH-fermented foods, it is unlikely that any combination of factors will permit prepared weaning foods to be held for longer periods of time, necessitating that primary consideration be given to dry foods that can be reconstituted before use or prepared fresh at each serving. It has been suggested that supplementation of formula or milk with antibodies against a range of enteropathogens could provide protection against diarrheal illnesses to infants. It has been shown that infants fed a formula containing cow milk immunoglobulin A excreted intact bovine immunoglobulins in their stool, but there is only limited evidence that such an approach would be efficacious in protecting infants from enteric diseases (Brüssow et al., 1987; Ebina et al., 1985; Tacket et al., 1988). Furthermore, even if the approach is efficacious, it is unlikely to be a feasible intervention to prevent diarrhea among children in developing countries. At best the approach might be used to protect high-risk infants for a short period of time in some settings, such as during hospitalization. But even for this limited application to be feasible, certain production and processing problems must be solved. Various bacterial organisms found in or added to food have been said to produce an intestinal microbial flora that protects the host against colonization with enteropathogens. These organisms, such as Lactobacillus acidophilus, Lactobacillus bulgaricus, and Streptococcus faecium, appear to survive passage through the stomach and remain in the upper small intestine for up to 6 hours (Clements et al., 1983). Although a protective effect has been found in some animal models, no preventive or therapeutic effect has been found in limited studies in humans. Selection of Processing Location Home and Village Preparation With proper education and a variety of foods, mothers and/or caretakers can prepare nutritious supplemental foods at home or in a communal village

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation setting (Valyasevi et al., 1984). Because the availability and cost of ingredients change with season and circumstance, nutritional knowledge is required to ensure proper formulation. Suggested food mixtures (Cameron and Hofvander, 1983) consist of cereal, legumes or lentils, animal protein, vegetables, sugar, and oil or fat in proportions to give a composition similar to that presented in Table 5-1. Vitamin supplementation normally depends on the addition of green or leafy vegetables and fruit since vitamin supplements are not common in developing countries. The use of local foods and ingredients reduces food costs and increases familiarity and acceptability. Major deterrents to this approach are the time required and the need for a separate cooking utensil to prepare a special food for a single child. This can be overcome by using village-level preparation of larger batches of food by mothers who share the food preparation responsibilities. The home and village preparation of foods containing legumes and lentils increases protein content, increases the cooking time, and requires the use of expensive and/or scarce cooking fuel (Harper and Tribelhorn, 1985). Central Processing Low-cost, shelf-stable supplementary foods made in factories and then distributed to the village appear to have their greatest utility in situations in which low-income families live in urban areas or the mother or caregiver is working. Hofvander and Underwood (1987) have described other circumstances in which the availability of centrally processed foods has particular value, for example, during failure of lactation in the mother, when catastrophe decreases food supplies, or when political upheaval dislocates families. Centrally processed foods have utility when convenience and time savings become critical to their use. A variety of central processing techniques have been used to produce nutritious food blends for weaning and supplementation (Harper and Jansen, 1985). Some of the processes are oriented toward the intermediate scale (500–1,000 kg/hour) and require lower skill levels and little imported processing equipment or technology. Other processes are adaptations of procedures used in developed countries to produce precooked cereals; they typically operate at capacities of several tons per hour and use imported equipment and technology. All are capable of producing a fully cooked, convenient, nutritious, and hygienic food product.

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation TABLE 5-1 Proposed Composition for Supplementary Foods   Amounts per 100 Grams Amounts per 100 kcal Protein1 (g) 20 5.2 Fat (g) 10 2.6 Crude fiber2 (g) 5 1.3 Acid-insoluble ash (g) 0.05 — Vitamin content3     Vitamin A, as retinol (μg) 400 100 Vitamin D (cholecalciferol) (μg) 10 2.5 Vitamin E (α-tocopherol) (μg) 5 1.25 Ascorbic acid (μg) 20 0.52 Thiamine (μg) 500 125 Riboflavin (μg) 800 200 Niacin (mg) 9 2.20 Vitamin B6 (μg) 900 220 Folic acid (μg) 100 27 Vitamin B12 (μg) 2 0.52 Mineral content     Calcium (mg) 800 200 Phosphorus (mg) 800 200 Iron (mg) 10 2.7 Iodine (μg) 70 18 1 Protein with a Score of 65 and PER 2.2 (Casein: 2.5). 2 Crude fiber higher than this may be acceptable, although it would require clinical testing. 3 The values for vitamins and minerals are considered minimal except in the case of vitamin D, where no further increase is desirable. The excess of each vitamin added during processing should be no greater than that needed to maintain label requirements ova the expected shelf life of the product. SOURCE: Food and Agriculture Organization/World Health Organization. 1982. Codex standard for foods for special dietary uses including foods for infants and children and related Code of Hygienic Practice, 1st ed. Codex Alimentarius 9:(I) Rome, Italy. The costs of centrally processed foods vary with the types of processes and products, scale of processing operation, and the fraction of the production capacity used. The lowest cost processes are roasting and low-cost extrusion, which add processing and packaging costs equivalent to about 30–50 percent of the cost of the raw ingredients. Intermediate cost processes include baking and high-moisture extrusion and add 50–100

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation percent of the cost of the raw ingredients. The highest cost processes are those that use high moisture cooking or fermentation and that require redrying. These processes may add 100–300 percent of the cost of the raw ingredient costs to the finished product. Centrally processed foods should be analyzed to ensure that they are free of pathogenic microorganisms, toxins, or other deleterious materials and that they meet nutritional guidelines such as those described by the Food and Agriculture Organization of the World Health Organization of the United Nations (FAO/WHO, 1982). COMPARISON OF STRATEGIES FOR SUPPLYING SUPPLEMENTAL FOODS Table 5-2 summarizes the reasons why both home and village and central processing are used to prepare weaning and supplementary foods (Valyasevi et al., 1984). The biggest advantage for village-prepared foods is cost and familiarity, whereas centrally processed foods are more easily prepared and have greater nutrient density. Precooked, centrally processed food is prepared by adding potable water, reducing the demand on cooking utensils and fuel, and meets the nutritional requirements of the child if it is fed to the child in proper amounts. Further, central processing techniques can increase the caloric density and facilitate fortification. Centrally processed foods often incorporate low-cost protein and fat-rich ingredients, such as dehulled whole soybeans, which are not commonly used in home or village preparations because of the lack of availability or difficulty in their preparation and use. Centrally processed supplementary foods have a higher cost. Costs range between US$0.50 and US$2.50/kg of dry food in a package. The proportion of cost associated with processing, packaging, and distribution varies between products and systems used, but increases the cost of the raw ingredients by 30 percent or more. Individual circumstances determine whether the nutritional value and convenience of the product justify the price since any increase can reduce the availability of the product to the poorest mother or caregiver or reduce the unsustainability of government distribution program. The shelf lives of centrally processed products are normally in excess of 6 months, with packaging protecting dry products from insects and moisture. Once opened, the products are vulnerable to deterioration. Assuming 50 g or more is fed per day, a 500-g package will be open for a maximum of 10 days, which minimizes such problems. Bacterial deterioration occurs if dry products become moistened.

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation TABLE 5-2 A Comparison of Techniques Used to Prepare Nutritious Foods for Weaning and Supplementation Home-or Village-Prepared Foods Centrally Processed Precooked Foods Advantages: • Lower cost by minimizing packaging and distribution • Cooking reduces risks associated with contamination • Traditional and familiar • Easy preparation • Higher nutrient density and improved digestibility • Increased shelf life • Formulated and fortified to meet nutritional requirements • Accommodates nontraditional ingredient, thereby expanding food supply Disadvantages: • More preparation time and effort • Requires special knowledge to formulate adequate food • Needs more fuel for cooking and a separate cooking utensil • Generally not fortified with vitamins and minerals • Increased cost associated with packaging and distribution • Less familiarity • Sharing if taken home SUMMARY Appropriately constituted weaning foods are necessary for infants to maintain normal growth when the quantity of breast milk becomes insufficient. Similar calorie-dense and nutritious foods can also be used to rehabilitate children after bouts of diarrhea and improve their nutritional status to better resist future exposure to diarrhea-causing agents. A number of food processes exist that can make suitable weaning foods. They vary in their ability to produce a completely satisfactory food product from the perspective of caloric density, nutritional composition, and storage stability. Fermentation, germination, and milling can be used to provide weaning foods with improved attributes. Processes such as roasting and extrusion that require little moisture are the lowest-cost small-scale industrial technologies, but they are not readily available to home application. Central processing of weaning foods increases their cost but improves their quality and convenience. Home preparation is time-consuming but increases familiarity and lowers the cost.

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation REFERENCES Aykroyd, W.R., and J. Doughty. 1964. Legumes in human nutrition. FAO Nutritional Studies No. 19. Food and Agriculture Organization of the United Nations. Rome, Italy. 138 pp. Barrell, R.A.E., and M.G.M. Rowland. 1980. Commercial milk products and indigenous weaning foods in a rural West African environment: A bacteriological perspective J. Hyg. Camb. 84:191–202. Bressani, R., J. Harper, and B. Wickström. 1984. Processed and packaged weaning foods: Development, manufacture and marketing. Pp. 117– 447 in K. Mitzner, N. Scrimshaw, and R. Morgan, eds. Improving the Nutritional Status of Children During the Weaning Period. Intl. Food and Nutr. Program, MIT, Cambridge, Mass. Brüssow, H., H. Hilpert, I. Waltlier, J. Sidoti, C. Mietens, and P. Bachmann. 1987. Bovine milk immunoglobulins for passive immunity to infantile rotavirus gastroenteritis. J. Clin. Microbiol. 25:982 –986. Cameron, M., and Y. Hofvander. 1983. Manual on Feeding Infants and Young Children, 3rd ed. Oxford University Press, Oxford. Clements, M.L., M.M. Levine, P.A. Ristaino, V.E. Daya, T.P. Hughes. 1983. Exogenous Lactobacilli: Fed to man—their inability to prevent disease. Prog. Fd. Nutr. Sci. 7:2937. Ebina, T., A. Sato, K. Umezu, N. Ishida, S. Ohyama, A. Oizumi K. Aikawa, S. Katagiri, N. Katsushima, A. Imai, S. Kitaoka, H. Suzuki, and T. Konno. 1985. Prevention of rotavirus infection by oral administration of cow colostrum containing antihuman rotavirus antibody. Med. Microbiol. Immunol. 174:177–185. FAO/WHO (Food and Agriculture Organization/World Health Organization). 1982. Codex standard for foods for special dietary uses including foods for infants and children and related Code of Hygienic Practice, 1st ed. Codex Alimentarius 9:(I) Rome, Italy. Genigeorgis, C.A. 1981. Factors affecting the probability of growth of pathogenic microorganism in foods. J. Am. Vet. Med. Assoc. 179:1410 –1417. Harper, J.M., and G.R. Jansen. 1985. Production of nutritious precooked foods in developing countries by low-cost extrusion technology. Food Rev. Int. 1:27–97. Harper, J.M., and R.E. Tribelhorn. 1985. Comparison of relative energy costs of village-prepared and centrally processed weaning foods. United Nations University. Food Nutr. Bull. 7(4):54–60. Hofvander, Y., and B.A. Underwood. 1987. Processed supplementary foods for older infants and young children, with special reference to developing countries. United Nations University. Food Nutr. Bull. 9(1):1–7. Jenkins, D.J.A., A.L. Jenkins, T.M.S. Wolever, L.H. Thompson, and A.V. Rao. 1986. Simple and complex carbohydrates. Nutr. Rev. 44:44 –49. Mosha, A.C., and U. Svanberg. 1983. Preparation of weaning foods with high nutrient density using flour of germinated cereals. United Nations University. Food Nutr. Bull. 5(2):10–14. Nelson, A.I., L.S. Wei, and N.P. Steinberg. 1978. Food products from whole soybeans. Pp. 21–24 in Whole Soybeans for Home and Village Use. INSOY Series #14. University of Illinois at Urbana-Champaign. Nout, M.J.R., G. Beernink, and T.M.G. Bonants-van Laarhoven. 1987. Growth of Bacillus cereus in soybean tempeh. Int. J. Food Microbiol. 4:293–301. Olkku, J., and C. Rha. 1978. Gelatinization of starch and wheat flour starch—A review. Food Chem. 3:293–317. Steinkraus, K.H., R.E. Cullen, C.S. Pederson, L.F. Nellis, and B.K. Gavitt. 1983. Indigenous fermented foods involving an acid fermentation: Preserving and enhancing organoleptic and nutritional qualities of fresh foods. Pp. 95–299 in K.H. Steinkraus, ed. Handbook of Indigenous Fermented Foods. Marcel Dekker, New York.

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Nutrition Issues in Developing Countries: Part I: Diarrheal Diseases - Part II: Diet and Activity During Pregnancy and Lactation Tacket, C.O., G. Losonsky, H. Link, Y. Hoang, P. Guesry, H. Hilpert, and M.M. Levine. 1988. Protection by milk immunoglobulin concentrate against oral challenge with enterotoxigenic Escherichia coli, N. Engl. J. Med. 318:1240–1243. Valyasevi, A., S. Colgate, R. Morgan, and K. Mitzner. 1984. Home-and village-level weaning-food projects. Pp. 101–115 in K. Mitzner, N. Scrimshaw, and R. Morgan, eds. Improving the Nutritional Status of Children During the Weaning Period. Intl. Food and Nutr. Program. MIT, Cambridge, Mass. Wang, Y.Y.D., and M.L. Fields. 1978. Germination of corn and sorghum in the home to improve nutritive value J. Food Sci. 43:1113–1115.

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