Detecting Micro- and Nanoplastics Released from Food Packaging: Challenges and Analytical Strategies

Original experiments on polyethylene cooking and ice-cube bags, together with nylon tea bags, illustrate the challenges of identifying and quantifying material released from food packaging.

Source details

Claudia Cella, Rita La Spina, Dora Mehn, Francesco Fumagalli, Giacomo Ceccone, Andrea Valsesia, Douglas Gilliland. Polymers. 2022.

DOI: 10.3390/polym14061238

Findings

Original experiments on polyethylene cooking and ice-cube bags, together with nylon tea bags, illustrate the challenges of identifying and quantifying material released from food packaging.

Commercial PE ice-cube bag: Raman identified PE particles mixed with ultramarine blue pigment and separate pigment particles. Room-temperature bag-contact control showed few visible particles, mainly PE. PDF p. 3 §2.2; pp. 6-7 Figure 1A and discussion.

Commercial PE rice-cooking bag with rice removed before test: Raman identified PE along with residual rice material. Boiled-water blank showed no PE or rice particles. PE mass by KBr-pellet FTIR was below the method detection limit. PDF p. 3 §2.2; pp. 6-7 Figure 1B and discussion; p. 9 mass quantification discussion.

For the ice-cube-bag test, bags contained 300 mL ultrapure water and were frozen at -20 °C for 24 h. The ice was manually removed into glass and thawed at room temperature. For the rice-cooking-bag test, the rice was removed before the bag was boiled in 250 mL ultrapure water at 100 °C for 10 min. These conditions belong to the studied bags and do not describe consumer zip-top storage bags. Source: PDF p. 3, section 2.2; pp. 6-7, Figure 1 and discussion.

Methods and scope

Raman microscopy identified polymer material; electron microscopy and XPS supplied complementary characterization. Calibrated FTIR assessed polymer mass. The study discusses laboratory blanks, unheated controls, and effects of sample concentration and preparation.

What this source can support

Supports qualitative findings for the specified cooking and ice-cube bags and explains measurement limitations. It does not supply a numerical particle-release rate used here, and the studied bags are not household zip-top storage bags.

Particle appearance and number depend on concentration, deposition, drying, cooling and aggregation. Polymer mass cannot be automatically converted to a particle count. Authors explicitly warn simple spotting is insufficient to quantify released particle number. Original sources studied are not zip-top storage bags. No numerical particle release rate for the bag experiments is used here.

Related evidence

Plastic food storage · How microplastics are measured