Mold species and fungi load of washed and unwashed table eggs

Abstract

Egg quality has been widely studied, mainly because defects in quality can pose risks to public health, as well as economic losses. Nevertheless, studies about fungi in eggs are scarce. The objective was to compare the fungal microbiota from washed and unwashed eggs in the rainy season and dry season of the year. This exploratory research consisted in the analysis of large size white table eggs acquired from 48 different lots. Two manufacturers were sampled considering the main characteristic of washed or unwashed eggs. From each lot, a 30-egg pack were purchased and six of those eggs were used for mycological analyzes. The eggs were analyzed externally with 0.1% peptone salt solution wash of the eggshells and internally with aliquots being sampled from a pool made from the six eggs content. Samples were inoculated in Potato Dextrose Agar and isolated colonies were passed to test tubes. When sporulated, the isolates were subjected to decimal dilutions using 0.1% Tween 80 to dissociate the conidia. Microcultures were carried out for optical microscopy observation of the reproductive structures of fungi, stained with lactophenol. Aspergillus spp. was the most frequently isolated fungi isolated, with A. niger and A. flavus predominant in the dry season, while A. fumigatus and A. terreus in the rainy season. Low numbers of fungi were identified from egg shells, with a higher amount from unwashed eggs. The season did not influence the number of fungi in eggs, despite having influenced the fungal diversity.