infants who are breastfed. some studies have found an association between infant formula and lower cognitive development, including iron supplementation in baby formula being linked to lowered i.q. and other neurodevelopmental delays; however other studies have found no correlation. causation, however, has not been established for negative long-term health effects of infant formula; studies analyzing health outcomes for breastfed vs. formula fed babies are primarily observational in nature and are plagued with confounding factors such as socioeconomic status, education level, and maternal preexisting conditions (such as obesity, which is associated with both low milk production and childhood obesity). when confounding factors are controlled for, differences between long-term health of breastfed and formula fed infants decrease. melamine contamination main article: 2008 chinese milk scandal in 2008, a case of melamine poisoning of infant formula was discovered in china, where milk was deliberately adulterated with the chemical, leading to the death of six babies, and illnesses in more than 300,000 infants, including cases of acute kidney failure. large quantities of melamine were added to watered-down milk to give it the appearance of having adequate protein levels. some of those responsible for the poisoning were sentenced to death. in november 2008, traces of melamine were reported to have been found by the u.s. food and drug administration in infant formula sold in the united states made by the three main american firms — abbott laboratories, nestlé and mead johnson — responsible for 90–99% of the infant formula market in that country. the levels were much less than those reported in china, where levels of melamine contamination had reached as much as 2,500 parts per million, about 10,000 times higher than the recorded us levels. the safety data sheet for melamine (cas registry number 108-78-1; c3-h6-n6) recorded the acute oral toxicity (median lethal dose) at 3161 mg/kg for a rat. health canada conducted a separate test and also detected traces of melamine in infant formula available in canada. the melamine levels were well below health canada's safety limits, although concerns remain about the safety of manufactured food for infants and monitoring of potentially dangerous substances. other health controversies in 1985, syntex corporation was ordered to pay $27 million in compensation for the deaths of two american infants who suffered brain damage after drinking the company's baby formula, called neo-mull-soy. formulas produced by syntex had previously been subject to a major recall as they were found to have insufficient chloride to support normal infant growth and development. in 2003, baby plant-based formula manufactured by the german company humana and sold in israel under the brand remedia caused severe vitamin deficiencies in babies. babies who consumed the formula were hospitalized with cardiac and neurological symptoms. three of them died, and at least twenty others were left with severe disabilities. an investigation revealed that the formula contained a much lower quantity of thiamine than is needed for healthy infant development because of a manufacturing error. humana's chief food technologist received a 30-month prison sentence for negligent manslaughter in february 2013 over the case. in 2010, abbott laboratories issued a voluntary recall of about five million similac brand powder infant formulas that were sold in the united states, guam, puerto rico and some caribbean countries. the recall was issued after the presence of a 'small common beetle' was detected in the product. in canada, new zealand and elsewhere, public concerns have been raised over the continued sale and marketing of soy-based formulae potentially containing high levels of phytoestrogens, linked to abnormal child development including damage to babies' thyroid glands. in december 2011 wal-mart recalled a quantity of infant formula after a baby died in missouri. "we extend our deepest condolences to this baby boy's family as they try to come to grips with their loss," said dianna gee, a wal-mart spokeswoman. "as soon as we heard what happened, we immediately reached out to the manufacturer of the formula and to the department of health and senior services to provide any information we may have to help with the investigation." wal-mart said it pulled a batch of enfamil from its stores nationwide that matched the size and lot number zp1k7g of the formula that may have sickened the baby in missouri, gee said. the baby formula was purchased from a wal-mart in lebanon, missouri. after the purchase, a 10-day-old infant died from a rare bacterial infection, cnn affiliate kytv reported. authorities ran tests to determine if the death came from the formula, the water to make the formula or any other factor, said mead johnson nutrition, the company that makes enfamil. "we are highly confident in the safety and quality of our products – and the rigorous testing we put them through," said chris perille, a mead johnson nutrition spokesman. preparation and content variations infant formulas come in powder, liquid concentrate, and ready-to-feed forms. they are designed to be prepared by the parent or caregiver in small batches and fed to the infant, usually with either a cup or a baby bottle. infant formulas come in a variety of types: cow's milk formula is the most commonly used type. the milk has been altered to resemble breast milk. soy protein based formulas are frequently used for infants allergic to cow's milk or lactose. soy-based formulas can also be useful if the parent wants to exclude animal proteins from the child's diet. protein hydrolysate formulas contain protein that's been broken down into smaller sizes than are those in cow's milk and soy-based formulas. protein hydrolysate formulas are meant for babies who do not tolerate cow's milk or soy-based formulas. specialized formulas are also available for premature infants and those with specific medical conditions. manufacturers and health officials advise it is very important to measure powders or concentrates accurately to achieve the intended final product concentration; otherwise, the child will be malnourished. it is advisable that all equipment that comes into contact with the infant formula be cleaned and sterilized before each use. proper refrigeration is essential for any infant formula which is prepared in advance. in developing countries, formula is frequently prepared improperly, resulting in high infant mortality due to malnutrition and diseases such as diarrhea and pneumonia. this is due to lack of clean water, lack of sterile conditions, lack of refrigeration, illiteracy (so written instructions cannot be followed), poverty (diluting formula so that it lasts longer), and lack of education of mothers by formula distributors. these problems and resulting disease and death are a key factor in opposition to the marketing and distribution of infant formula in developing countries by numerous public health agencies and ngos (discussed in more detail at nestlé boycott and international code of marketing of breast-milk substitutes). nutritional content besides breast milk, infant formula is the only other milk product which the medical community considers nutritionally acceptable for infants under the age of one year (as opposed to cow's milk, goat's milk, or follow-on formula). supplementing with solid food in addition to breast milk or formula begins during weaning, and most babies begin supplementing about the time their first teeth appear, usually around the age of six months. although cow's milk is the basis of almost all infant formula, plain cow's milk is unsuited for infants because of its high casein content and low whey content, and untreated cow's milk is not recommended before the age of 12 months. the infant intestine is not properly equipped to digest non-human milk, and this may often result in diarrhea, intestinal bleeding and malnutrition. to reduce the negative effect on the infant's digestive system, cow's milk used for formula undergoes processing to be made into infant formula. this includes steps to make protein more easily digestible and alter the whey-to-casein protein balance to one closer to human milk, the addition of several essential ingredients (often called "fortification", see below), the partial or total replacement of dairy fat with fats of vegetable or marine origin, etc. the nutrient content of infant formula for sale in the united states is regulated by the food and drug administration (fda) based on recommendations by the american academy of pediatrics committee on nutrition. the following must be included in all formulas produced in the u.s.: protein fat linoleic acid vitamins: a, c, d, e, k, thiamin (b1), riboflavin (b2), b6, b12 niacin folic acid pantothenic acid calcium minerals: magnesium, iron, zinc, manganese, copper phosphorus iodine sodium chloride potassium chloride carbohydrates carbohydrates are an important source of energy for growing infants, as they account for 35 to 42% of their daily energy intake. in most cow's milk-based formulas, lactose is the main source of carbohydrates present, but lactose is not present in cow's milk-based lactose-free formulas nor specialized non-milk protein formulas or hydrolyzed protein formulas for infants with milk protein sensitivity. lactose is also not present in soy-based formulas. therefore, those formulas without lactose will use other sources of carbohydrates, such as sucrose and glucose, dextrins, and natural and modified starches. lactose is not only a good source of energy, it also aids in the absorption of the minerals magnesium, calcium, zinc and iron. human milk oligosaccharides (hmos) hmos are naturally occurring sugars found in human breast milk, they improve the immune system and act as nutrients to beneficial gut bacteria. some manufacturers also use human milk oligosaccharides as a modern infant formula supplement to give additional health benefits to their products, however they are not found all types of formula. nucleotides nucleotides are compounds found naturally in human breast milk. they are involved in critical metabolic processes, such as energy metabolism and enzymatic reactions. also, as the building blocks of deoxyribonucleic acid (dna) and ribonucleic acid (rna), they are essential for normal body functions. compared to human breast milk, cow's milk has lower levels of the nucleotides uridine, inosine, and cytidine. therefore, several companies that produce infant formula have added nucleotides to their infant formulas. other commonly used ingredients: emulsifiers and stabilizers: ingredients added to prevent the separation of the oil from the water (and its soluble components) in the infant formula. some commonly used emulsifiers include monoglycerides, diglycerides, and gums. diluents: skim milk is commonly used as the primary diluent in milk-based liquid formula to provide the bulk of the volume. in contrast, purified water is the most commonly used diluent in milk-free formulations. policy, industry and marketing the policy, regulatory and industry environments surrounding the infant formula market vary tremendously between countries. international the international code of marketing of breast-milk substitutes is an international health policy framework adopted by the world health assembly of the who in 1981 regarding infant formula marketing, including strict restrictions on advertising. its implementation depends on the laws of different countries and the behavior of infant formula manufacturers – the code has no power itself. legislation and corporate behavior vary significantly between countries: at least 84 countries have enacted national legislation implementing all or many of the provisions of the code and 14 countries have draft laws awaiting adoption; whereas elsewhere neither the code nor its principles are followed by governments or formula manufacturers. practices that are banned in the code include most advertising, claiming health benefits for formula, and giving free samples to women able to breastfeed – this latter practice is particularly criticized because it can interfere with lactation, creating dependence on formula, without proper education on ensuring continued breast stimulation while formula is being used. in many countries free samples of infant formula have been provided to hospitals for decades; infant formula is often the only product routinely provided free of charge to hospitals. the baby friendly hospital initiative (bfhi) aims to reduce and eliminate this controversial practice; however, there is increasing criticism of the bfhi's rigidity in limiting use of infant formula, which can be an appropriate treatment for common conditions such as suboptimal intake jaundice, and may cause mothers to feel pressured or guilted into breastfeeding. philippines infant formula is one of the top three consumer commodities in the philippines, and among the most imported products. annual sales amount to some us$469 million annually. us$88 million is spent on advertising the product. infant formula marketing has been regulated since the 1987 executive order 51 or "milk code", which regulated, but did not ban, practices such as advertising and providing free samples. shortly after it was enacted, wyeth introduced