Holder-Pasteurized Human Donor Milk: How Long Can It Be Preserved?

OBJECTIVE: When own mother's milk falls short, pasteurized human donor milk is recommended as alternative feeding for preterm infants. Donor milk has to meet the highest safety standards, but its processing and storage is expensive. The recommended storage time of pasteurized donor milk is 3 months. The objective of the present study was to determine whether the frozen storage time of pasteurized donor milk can be extended beyond 3 months without compromising its safety and quality. METHODS: For this prospective observational study breast milk samples of 34 unique women, collected between November 2014 and June 2015, were provided by the Dutch Human Milk Bank. Samples were Holder pasteurized within 3 months after expression and stored at -20°C. Analysis of both bacterial growth (by inoculation of milk on a blood and a cysteine-, lactose-, and electrolyte-deficient agar) and fat, crude protein, carbohydrate and energy content of milk (analyzed by infrared spectroscopy) was done monthly during the first 6 months and every 2 months thereafter, up to 1 year postpasteurization. RESULTS: Thirty of 306 (9.8%) follow-up samples showed bacterial growth when cultured. None of the samples showed sequential contamination with the same strain up to 8 months of frozen storage. No significant decreases in macronutrients and energy content were observed over 8 months. CONCLUSION: Pasteurized human donor milk can be stored safely for 8 months at -20°C, without compromising its macronutrient and energy content. This longer storage time will reduce disposal of expired donor milk and subsequently reduce costs.

Pre-weaning dietary iron deficiency impairs spatial learning and memory in the cognitive holeboard task in piglets.

Iron deficiency is the most common nutritional deficiency in humans, affecting more than two billion people worldwide. Early-life iron deficiency can lead to irreversible deficits in learning and memory. The pig represents a promising model animal for studying such deficits, because of its similarities to humans during early development. We investigated the effects of pre-weaning dietary iron deficiency in piglets on growth, blood parameters, cognitive performance, and brain histology later in life. Four to six days after birth, 10 male sibling pairs of piglets were taken from 10 different sows. One piglet of each pair was given a 200 mg iron dextran injection and fed a control milk diet for 28 days (88 mg Fe/kg), whereas the other sibling was given a saline injection and fed an iron deficient (ID) milk diet (21 mg Fe/kg). Due to severely retarded growth of two of the ID piglets, only eight ID piglets were tested behaviorally. After dietary treatment, all piglets were fed a balanced commercial pig diet (190-240 mg Fe/kg). Starting at 7.5 weeks of age, piglets were tested in a spatial cognitive holeboard task. In this task, 4 of 16 holes contain a hidden food reward, allowing measurement of working (short-term) memory and reference (long-term) memory (RM) simultaneously. All piglets received 40-60 acquisition trials, followed by a 16-trial reversal phase. ID piglets showed permanently retarded growth and a strong decrease in blood iron parameters during dietary treatment. After treatment, ID piglets' blood iron values restored to normal levels. In the holeboard task, ID piglets showed impaired RM learning during acquisition and reversal. Iron staining at necropsy at 12 weeks of age showed that ID piglets had fewer iron-containing cells in hippocampal regions CA1 and dentate gyrus (DG). The number of iron-containing cells in CA3 correlated positively with the average RM score during acquisition across all animals. Our results support the hypothesis that early-life iron deficiency leads to lasting cognitive deficits. The piglet as a model animal, tested in the holeboard, can be useful in future research for assessing long-term cognitive effects of early-life diets or diet-induced deficiencies.