## 3 Presence of Micro- and Nanoplastics in Environmental Matrices and Food
### Food  
Food and food contact materials represent significant sources of plastic particles for human ingestion.  
NPs, along with plastic particles of higher dimensions, depending on their composition, have the capacity to infiltrate various parts of vegetables, such as seeds, roots, leaves, and fruits. For instance, studies have detected plastic particles in the root cap mucilage (200 nm) and leaves (100 nm) of lettuce; in the roots (1219.7 nm) and leaves (607.2 nm) of carrots; in radish roots (300 nm-2 \(\upmu\)m); and in seeds and fruits such as peas (20 nm), apples (2.17 \(\upmu\)m), pears (1.99 \(\upmu\)m), and cabbage (2.10 \(\upmu\)m) [54; 55; 56; 57].  
Studies have shown the presence of microplastics (MPs) in milk, with concentrations ranging from 6.5 \(\pm\) 2.3 to 40 particles per liter (p/L) and dimensions measuring <11-6700 \(\upmu\)m. In the case of honey, there is significant variation in microplastic concentrations, with ranges from 10 to 9000 \(\upmu\)m and from 22-76 to 36-114 p/kg for craft or industrial origin, respectively. Similarly, sea salt demonstrates considerable variability in contamination levels, ranging from a few particles to 31,680 p/kg and dimensions varying from 1 to 9360 \(\upmu\)m [15].  
[PERSON] and co-authors reviewed the presence and concentrations (as p/g) of MPs and NPs in oysters and bivalves and report that oysters and other bivalves contain MPs of <1-250 \(\upmu\)m and 0.2 to 5.8 p/g wet weight. In particular, mussels have been found to contain MPs from 0.12 to 2.3 p/g wet weight [14]. Data on wild-caught fishes indicate varying contamination levels, with values ranging from 0.43 \(\pm\) 0.69 p/individual in 24 different species from the East China Sea to 14-94 p/individual in Taiwan. It is worth noting that these concentrations are primarily derived from analyses of the gastrointestinal tract and gill tissues rather than edible tissues [58].  
Moreover, food containers have been studied, and research conducted in China revealed that PP packages hold particles from 3 \(\pm\) 1.13 to 38 \(\pm\) 5.29 mg/pack in disposable plastic bags, and in PS packaged meat from 4 to 18.7 p/kg [59; 60]; particles of 113 nm-31.7 \(\upmu\)m in PE, PS, and PP food containers were also observed [61]. The heat from hot food and beverages stored in plastic containers accelerates the release of MPs and NPs. For example, [PERSON] et al. [62] reported the release of 25,000 MPs into 100 mL of hot water within 15 min from a paper cup, along with 102 \(\pm\) 21 \(\times\) 10\({}^{6}\) sub-micron particles (105 nm-4.2 \(\upmu\)m). Containers made of PP, PS, PE, and PET present MPs ranging from 3 to 29 items per container [63]. Even PP feeding bottles can harbor over 16 million p/L [64], while plastic teabags release roughly 11.6 billion MPs and 3.1 billion NPs into a cup at brewing temperature [65; 66].  
Plastic degradation from packaging and cross-contamination are the primary pathways through which MPs and NPs infiltrate food sources. Once ingested, these particles can undergo fermentation by gut microbiota, particularly within the upper gastrointestinal tract [67]. Understanding the extent to which MPs and NPs permeate both the environment and the food chain is crucial for assessing their potential risks to human health.