2.6. Food frequency questionnaire
The FFQ was elaborated on the basis of the population consumption
habits of foods susceptible to aflatoxin contamination
and regulated in Brazil (Agência Nacional de Vigilância Sanitária,
2011, p. 72). Some food items like corn flour are used to prepare
different processed foods and thus these foods were also included
in the questionnaire aiming to cover as many foods consumed as
possible. Consumption frequency was measured by a range starting
from less than once a month until twice every day. Portion sizes
were chosen for each food item according to usual measures, cups
for milk, slices for cheese and tablespoon for cereals. A blank space
was also available if the volunteers needed to express a different
consumption pattern. The FFQ was applied to thirty-five individuals
living in residences from where food samples were collected. The
body weight of each individual was also recorded to calculate the
PDI value by the following expression: PDI ¼ (mean concentration
of aflatoxins mean consumption of food type)/(each individual
body weight).