Analysis of aflatoxin M1 contamination in milk and cheese produced in Mexico: a review

Due to the carcinogenic character of aflatoxins when present in foods, these compounds are considered a risk to human health. This systematic review aimed at compiling the available research data on detection and quantification of aflatoxin M1 (AFM1) in milk and common types of cheese produced in Mexico in the past two decades. A limited number of studies were found that matched the purpose of our review. Only ten research works focused on the evaluation of AFM1 content in milk while three studies analysed the occurrence of this mycotoxin in oaxaca and panela cheeses. HPLC-FD and ELISA were the methods of choice utilised to detect AFM1. Concentrations higher than 0.5 μg AFM1/kg, a maximum limit set in current food regulation in Mexico, were found in major dairy brands consumed in Mexico. Analysis of raw milk produced during the rainy season in the states of Jalisco (2007) and Chiapas (2013) showed mycotoxin levels within the regulation limits while milk samples obtained during the dry season in the Mexico City and the State of Mexico (2008) exceeded that threshold. For cheeses, 33% of the artisanal produced oaxaca type samples from Veracruz (2016) and 55% of those acquired in Mexico City (2019) were found above the limit set for milk. In contrast, the panela cheese samples obtained in Baja California and Guanajuato (2009) complied with the AFM1 regulation. Additionally, the presence of AFB1 and its hydroxylated metabolites other than AFM1 were determined in the major milk brands at concentrations that could be of high risk for human health. Similar results were reported for both artisan and industrially produced oaxaca cheese. Finally, mycotoxins enter human food chain through animals fed with contaminated fodder. Our systematic review demonstrated the urgent need to amend the existing food regulation in Mexico to include mycotoxins as potent contaminants in cheese.

Symbol Digit Modalities Test: Normative data for Spanish-speaking pediatric population

OBJECTIVE

To generate normative data for the Symbol Digit Modalities Test (SDMT) in Spanish-speaking pediatric populations.

METHOD

The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the SDMT as part of a larger neuropsychological battery. SDMT scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses.

RESULTS

The final multiple linear regression models showed main effects for age in all countries, such that score increased linearly as a function of age. In addition, age2 had a significant effect in all countries, except in Honduras and Puerto Rico. Models indicated that children whose parent(s) had a MLPE >12 years of education obtained higher score compared to children whose parent(s) had a MLPE ≤12 years for Chile, Guatemala, Mexico, and Spain. Sex affected SDMT score for Paraguay and Spain.

CONCLUSIONS

This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate interpretation of the SDMT with pediatric populations.