Analytical Variability in Microplastic Quantification: A Narrative Review of Commercial Beverages

Microplastics (MPs) have been reported in commercial beverages, but substantial differences in study design make direct comparisons difficult. This non-systematic, focused narrative review critically synthesizes a purposively selected core set of 17 particle-count studies published from 2020 to 2026 on soft drinks, beer, wine, tea, coffee, juices, energy drinks, and related beverages, while considering recent complementary thermal-analysis evidence. Data were compared for study location, beverage type, analytical method, abundance, particle size, morphology, color, polymer composition, and packaging. Fourier-transform infrared spectroscopy-based methods were most common; Raman spectroscopy, fluorescence microscopy, scanning electron microscopy, and laser direct infrared imaging were used in selected studies. Reported soft-drink concentrations ranged from approximately 0.30 particles/L to 166 ± 62 particles/100 mL (1660 ± 620 particles/L), but these values cannot support a geographic ranking because minimum particle-size thresholds, confirmation criteria, blank corrections, sample volumes, and reporting units differed. Fibers and fragments were the dominant morphologies, and polyethylene terephthalate, polyethylene, polypropylene, and polyamide were frequently identified. Findings from beverages packaged in glass and aluminum, as well as plastic, indicate that source water, ingredients, processing equipment, filtration, closures, ambient deposition, and packaging can all contribute. Current intake estimates describe potential particle ingestion rather than absorbed dose or toxicological impact. Because current data largely reflect analytical sensitivity rather than true contamination gradients, this review demonstrates that reliable cross-study exposure assessments currently remain associated with considerable uncertainty, and this uncertainty will be difficult to resolve until particle-count data are normalized to harmonized size thresholds and paired with mass-based thermal analyses.