Identification of Microplastics in Corn Tortillas in Morelos, Central Mexico

Tortillas are an essential food in Mexico, and they are usually packaged in low-density polyethylene (LDPE) bags, but these packages can release microplastics (MPs) into the food. On the other hand, MPs have been associated with conditions such as the release of toxic substances, damage to mitochondrial membranes, and the generation of oxidative stress and inflammation, among others. Currently, there are no studies on the presence of MPs in corn tortillas, so the objective of this work was to study samples of tortillas acquired at five points of sale in central Mexico, namely, supermarkets (A and B) and tortilla shops (C, D, and E), as well as to evaluate the presence of MPs and their identification by Fourier-transform infrared spectroscopy (FTIR), optical microscopy, and scanning electron microscopy (SEM). In addition, an abundance interval and an estimate of the consumption rate were established considering the available information on per capita consumption of tortillas in Mexico. The results show that the samples of tortillas purchased at sampling points A and B presented MPs in the form of films with an abundance between 155.56 and 177.78 MPs/kg of tortilla; however, no microplastics were identified in the samples of tortillas acquired at sites C, D, and E. The analysis suggests that the identified MPs may have come from the plastic bags in which tortillas are packaged. In addition, it was established that the daily consumption rate of microplastics per person is 2.48 to 5.15 pieces.