Survey of infant formulas consumed in Brazil for macrolide antimicrobial residues

Resumo

Infant formulas are used as a substitute or a food supplement for breast milk. Although
being strictly regulated manufactured products chemical residues and contaminants may
be present. Animals’ milk (mainly cow’s milk) is the primary ingredient in the
manufacturing of the majority of infant formulas and may be a source of chemical
contamination. Veterinary drug residues can be present due to the use of these
substances in milk producing animals. Macrolide antimicrobials have already been
designated as critically important for both human and animal health and should be
prioritized for actions to combat the threat posed by antimicrobial resistance. A liquid
chromatography–tandem mass spectrometry (LC–MS/MS) method, based on a modified
QuEChERS alkaline extraction, which has been in-house developed and validated, was
used for the identification and quantification of macrolide residues in infant formula
sold in the states of Rio de Janeiro, Pernambuco, Mato Grosso do Sul and Rio Grande
do Sul, Brazil, from 2018-2021. The method, quantitative for erythromycin, spiramycin,
oleandomycin, and tylosin, and qualitative for tilmicosin, was applied to 80 samples and
the results showed a high incidence of macrolide residues (52.5%). Spiramycin was
detected in 51.3% of samples, with a method limit of detection of 0.11 µg L1 for readyto-eat infant formulas. In 21.3% of analyzed samples, more than one studied macrolide
was found. Since according to Brazilian regulations veterinary drug residues are not
allowed in infant formula, all these samples were considered non-compliant.