Researcher(s)
- Laurie Ziegler, Nutritional Science, University of Delaware
Faculty Mentor(s)
- Melissa Melough, Health Behavior and Nutrition Sciences, University of Delaware
Abstract
Background: Microplastics (MPs) are small plastic fragments (between 1 µm and 5mm) that are widespread in the environment due to breakdown of larger plastics. MP exposure can negatively affect the cardiovascular, gastrointestinal, respiratory, and reproductive systems. Infants may be particularly susceptible to these effects due to their underdeveloped immune systems and high exposure levels. Approximately 75% of US infants rely on formula as a primary source of nutrition, yet little is known about the presence of MPs in formula.
Objective: This study aimed to extract and characterize MPs in two different brands and types of infant formula.
Methods: We selected two top-selling formula brands, and within those, selected two types of powdered formula: standard formula designed to mimic breastmilk and extensively hydrolyzed formula intended for children with allergies and other digestive issues. We also prepared a laboratory blank to evaluate possible contamination.
Formulas were reconstituted with ultrapure water, and then digested with 30% H2O2 in a hot water bath for 12-16 hours. A sodium dodecyl sulfate solution was added prior to sonication for 30-120 minutes to aid lipid breakdown. Samples were then sequentially filtered through 80 and 120 µm sieves and vacuum filtered through a cellulose ester membrane with a 20-25 µm pore size. Membranes were analyzed via optical and scanning electron microscopy.
Results: Few suspected MPs were identified in the laboratory blank sample, suggesting adequate controls against contamination. Numerous MPs were found in all formula samples, with varied shapes including pellets, fragments, sheets, and fibers. Sizes of suspected MPs ranged from 20 to 60 µm. No clear differences in MP particle count, size, or shape were noted between hydrolyzed and standard formulas.
Conclusions: MPs were prevalent across all formulas examined. Additional research is necessary to confirm the chemical identity of these particles and quantitatively compare MPs between formula types.