The complementary feeding national programme (PNAC) delivers 2 kg-month of dried full-fat cow's milk (LP) to 0-1 year old infants. The purpose of this work was to design, produce and evaluate nutrient stability and shelf life of a modified LP milk formula (LPM), which seems nutritionally more adequate for infants and is of similar cost than LP, to be included into the PNAC. LPM has the following attributes: P% 12.0 (LP 21.8%): casein/whey proteins ratio: 40 to 50/60 to 50 (LP 80/20); more digestible fats; essential fatty acids: > or = 4% of total calories; vitamins and minerals which cover 100% daily requirements for 0 to 6 months old infants; protein and energy can be modulated between 1.5 and 2.25 g/100 ml and 50-75 kcal/100 ml respectively. Forty tons of LPM were produced in accordance with our specifications for a field study. Quality controls on the product showed the production feasibility of such a formula at a lower price than LP. To determine shelf life, periodical analysis of peroxides, available lysine, ascorbic acid and linoleic acid were carried out in LPM stored for 1 year at 20 degrees C and 37 degrees C. It was found that LPM has an optimum shelf life of 7 months when packed in the same material that is now being in use for LP.(ABSTRACT TRUNCATED AT 250 WORDS)