Microbial quality of edible seeds commercially available in southern Portugal

Abstract

<abstract> <p>In the present work, the microbiological quality of sesame, flaxseed, chia, pumpkin sunflower seeds, a mix of seeds, as well as flaxseed flour, marketed in southern Portugal, were studied through the counting of aerobic microorganisms at 30 °C (AM), molds and yeast (M&amp;Y), <italic>Escherichia coli</italic> (β-glucuronidase positive) (β-GP <italic>E. coli</italic>), <italic>Staphylococcus</italic> coagulase positive, and detection of <italic>Salmonella</italic> spp. The persistence of AM and M&amp;Y populations were also counted in organic and non-organic flaxseed at 20 °C for 11 months. The seeds with the highest average of AM were flaxseed (1.3 x 10⁶ CFU/g) followed by flaxseed flour (1.1 x 10⁶ CFU/g) while the lowest level was found in chia (2.9 x 10⁴ CFU/g). This seed also presented the lowest average values of filamentous fungi (9.8 x 10² CFU/g), whereas sunflower seeds had the highest levels (1.7 x 10⁵ CFU/g). Flaxseed flour had the highest yeast counts (1.5 x 10⁴ CFU/g). Although some samples had high levels of AM and fungi, β-GP <italic>E. coli</italic> and <italic>Salmonella</italic> were not detected, therefore, they complied with the microbiological criteria of the European Union. The organic flaxseed contained higher numbers of AM and M&amp;Y than the non-organic ones (p &lt; 0.05). In addition, the storage of flaxseed at 20 °C resulted in changes of AM and M&amp;Y, showing that these populations were able to remain viable after eleven months (AM Log 5.4–Log 5.6; M&amp;Y Log 2.8–Log 4.1). The results obtained in the present study, namely those high levels of AM and fungi (&gt;10⁶ and 10⁴ CFU/g respectively), alert to the need of improving processing practices, storage/distribution conditions of edible seeds and derivatives, as well as the requirement of implementing adequate decontamination techniques.</p> </abstract>