Food packaging for direct consumption: quantification of microbial load and assessment of consumer health risks

Abstract

Direct consumption of foods from packaging that requires mouth contact with the external surface, such as soft drink cans and drinkable yogurts, may pose a microbiological risk. If these surfaces are not properly decontaminated, there is a potential for disease transmission. This study evaluated microbial contamination on yogurt and soft drink packaging, focusing on indicator microorganisms in areas that come into contact with the consumer’s mouth. A total of 24 samples were collected from a supermarket in a municipality in the Fronteira Oeste region, RS, during the winter and spring seasons, comprising 12 yogurt and 12 soft drink samples, equally distributed between two brands of each product. Microbiological sampling was standardized on a defined area of the packaging. Molds, yeasts, Enterobacteriaceae, coliforms at 35 °C, and coliforms at 45 °C were assessed. Contamination by molds and yeasts was high for both products and periods, with counts ranging from 0.4 to 46.5 CFU/cm², the highest being observed in brand A yogurt during spring. Enterobacteriaceae were detected in 25% of the groups, with elevated counts in brand A yogurt during winter. Coliforms were detected only in winter, present in all soft drink groups (both 35 °C and 45 °C) and in brand B yogurt (coliforms at 35 °C). Environmental conditions varied between periods, with higher humidity in winter. Yogurt temperatures remained within recommended limits, ranging from 1.73 to 5.68 °C. The study revealed contamination on packaging, highlighting significant counts of molds, yeasts, and Enterobacteriaceae in some of the evaluated groups. These findings indicate a potential risk to consumer health and underscore the importance of preventive measures and proper hygiene practices for packaging to avoid cross-contamination.