Skip to main content

Table 2 Occurrence and characteristics of microplastics in salts and sugar

From: Microplastics in food: scoping review on health effects, occurrence, and human exposure

Type of product

Type of polymer

N/Np

Size range (μm)

Analytical method

Microplastic content (particles/kg)a

Sample origin

Reference

Commercial salts, rock salt, lab-grade, and raw salt

PE, PP, PU, PET, PVC, and others, totalling 23 polymer types

24/24

65-2500

Stereo microscope+FTIR

11-193 (commercial)

64 (rock)

Shi Lanka

(Kapukotuwa et al. 2022)

Sea salts

PP, PE, and polyvinyl acetate

23/23

3.3–4460

Optical microscope +SEM-EDX

0.67 ± 1.15-3.42 ± 4.94

Africa

(Fadare et al. 2021)

Sea salts

PET, PVC, PE, PS, PA, PP

11/11

10–150

Microscopy+Micro FTIR

170–320 (Italy)

70-200 (Croatia)

Italy and Croatia

(Renzi et al. 2019)

Sea and rock salts

Anthropogenic debrisb

12/12

100-5000

Stereo microscope

46.7 -806

Global

(Kosuth et al. 2018)

Sea, lake, and rock salts

PE, PP, PET, PU, PVC, PA

16/16

20-5000

Micro-Raman spectroscopy

16–84 (sea salt)

8–102 (lake salt)

9–16 (rock salt)

Turkey

(Gündoğdu 2018)

Sea salts

PE, PS, PET, PA, polyester

8/8

< 500-5000

Digital microscope+FTIR

56 ± 49-103 ± 39

India

(Seth and Shriwastav 2018)

Sea, lake, and rock salts

PE, PP, PET

39/nr

100-5000

Stereo microscope +FTIR

0–1674 (sea salts)c

0–148 (rock salts)

28–462 (lake salts)

Global

(Kim et al. 2018)

Table salts

PE, PP, PET, PS, polyacrylonitrile, PA

17/15

160-980

Stereo microscope +Raman spectroscopy

0-10

Global

(Karami et al. 2017)

Sea and well salts

PET, PE, PP

21/21

30 -3500

Stereo microscope +FTIR

115-185 (well salts)

50-280 (sea salts)

Spain

(Iñiguez et al. 2017)

Refined and powdered sugar, unrefined cane sugar

Coloured fibres and fragments

6/6

10-9000

Stereo microscope

217 ± 123 (fibres)

32 ± 7 (fragments)

1100 (total fibres and fragments for cane sugar sample)

Germany

(Liebezeit and Liebezeit 2013)

  1. N/Np Number of samples/number of positive samples, nr Not reported
  2. aPresented as Range, Mean ± SD or Range of Mean ± SD
  3. bNot stained by the Rose Bengal dye
  4. cExcluding one outlier of 13,629 particles/kg