Knowledge about food classification systems and value attributes provides insight for understanding complementary food choices in Mexican working mothers.

Knowledge about mothers' perceptions of food classification and values about complementary feeding is necessary for designing educational and food supply interventions targeted to young children. To determine classification, attributes, and consumption/preparation routines of key complementary foods, 44 mothers of children < 2 y of age in 14 manufacturing businesses were studied. Using 31 key foods, we conducted free-listings, pile-sort, and food attributes exercises. Hierarchical clustering showed that mothers identified nine classes of key foods, including milk derivatives, complements, junk food, infant products, chicken parts, and other meats. From multidimensional scaling, mothers used three primary classification systems: food groups, food introduction stages, and food processing. Secondary classification systems were healthy-junk, heavy-light, hot-cold, good-bad fat, and main dish-complement. Child health and nutrition, particularly vitamin content, were salient attributes. Fruits and vegetables were preferred for initiating complementary feeding on the second month of age. Consumption of guava, mango, and legumes, however, was associated with digestive problems (empacho). Red meats were viewed as cold-type, heavy, and hard, not suitable for young children, but right for toddlers. Chicken liver was considered nutritious but dirty and bitter. Egg and fish were viewed as a vitamin source but potentially allergenic. Mothers valued vitamin content, flavor, and convenience of processed foods, but some were suspicious about expiration date, chemical and excessive sugar content and overall safety of these foods. Mothers' perceptions and values may differ from those of nutritionists and program designers, and should be addressed when promoting opportune introduction of complementary foods in social programs.