Home preparation of powdered infant formula: is it safe?

Breastfeeding is the natural way of feeding infants and young children. WHO recommends, as a public health measure, exclusive breastfeeding for 6 months and continued breastfeeding up to 2 years and beyond (1). Yet a large proportion of infants worldwide is formula fed (2,3). Of these, the largest majority is fed with powdered infant formula (PIF). In Italy in 1998, an estimated 15% of newborns were given PIF at discharge, up to 35% at 2 weeks and 90% at 5 months (4). A recent judicial inquiry estimated a consumption of about 11.7 kg of PIF per infant in 2004 (5). PIF is not a sterile product; it can be intrinsically, that is before the tin is opened for use, contaminated with bacteria (6). This has become a concern after the recent increase in the notification of serious cases and outbreaks of disease caused by Enterobacter sakazakii (7). This problem may be even more serious in selected groups (infants small for gestational age, preterm, immunocompromised, in the first 2 months of life) and in low-income countries where adequate diagnostic facilities are lacking (8). To address the problem, WHO has recently issued guidelines for the safe preparation, storage and handling of PIF (9). The objective of this study was to assess the practices of a sample of parents using PIF against the WHO guidelines. The study was carried out in Trieste on a sample of 131 infants recruited between April and July 2006 in immunisation centres. The infants were 1 week to 12 months old and to be enrolled had to take PIF, exclusively or as a supplement of breast milk and/or solid food, at the time of the interview. The sample size was based on the 95% probability of finding a 50% ± 10% prevalence of using water at ≥ 70◦C for the preparation of PIF. Data were analysed with SPSS and statistical associations were tested with Chi-square and Fisher’s exact test. A total of 124 mothers and 7 fathers were interviewed; 76% were married, 2% single and 22% were living with a partner; 47% were older than 35 years, 34% were 30– 34 years and 19% were 20–29 years old; 19% had a university and 62% a secondary school degree; 72% were working outside home, mostly full time; 67% had no other children. The 131 infants were evenly distributed by age; 12% had a birth weight less than 2500 g, 8% more than 4000 g; there were 7 couples of twins. PIF had been started at age 0–4 weeks in 37%, 5–12 in 47%, 13–40 in 16%; 33% were exclusively formula fed, 37% were still breastfed. Sixty-two percent of parents had been instructed on PIF preparation by health professionals, mostly in the hospital; the remaining parents were using the instructions found in the labels to prepare the product. Tables 1 and 2 show the practices reported by parents. After preparing a feed, 10% of parents store the bottle at room temperature and 3% in a bottle warmer; 16% use the stored feed within 4 h. Tests carried out during the study showed that bottle warmers reach a temperature of 70◦C in about 20 min; none of the parents using such a device was aware of this. Forty parents (31%) fill the bottle with cereals. Based on the four criteria set by WHO (sterilize the bottle at each feed, wash hands with warm water and soap before preparation, warm water at ≥ 70◦C then add PIF, use immediately and discard the remaining), only 15 parents (11%) prepare PIF safely. No association was found between safe PIF preparation and infant and parental variables. The fact that just over 10% of 131 parents with a medium to high level of education comply with the safety criteria set by WHO is a matter of concern. On the other hand, how could parents act differently if those were the instructions they got from health professional and/or read in the labels, despite the fact that guidelines similar to the WHO ones had been issued by the European Food Safety Authority (EFSA) and by the Italian National Institute of Health 2 years before? (8,10) Manufacturers also ignored a directive of the Ministry of Health issued on 15 March, 2006 and asking them to update the labels (11). Most labels instruct to prepare the feed with water at 40–45◦C; some labels do not even mention the temperature and generically say to use warm water. These temperatures do not inactivate Enterobacter sakazakii (12). Manufacturers probably pay attention to the warnings of both EFSA (8) and ESPGHAN (13) about the possible loss of nutritional value of using water at 80–90◦C.