Microbial quality of edible seeds commercially available in southern Portugal

• Published in: AIMS microbiology 2022-01, Vol.8 (1), p.42-52
• Main Authors: Silva, Daniela, Nunes, Patrícia, Melo, Jessie, Quintas, Célia
• Format: Article
• Language: English
• Subjects: chia; edible seeds; flaxseed; microbial quality; pumpkin; sesame; sunflower
• ISSN: 2471-1888; 2471-1888
• DOI: 10.3934/microbiol.2022004

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&Y), (β-glucuronidase positive) (β-GP ), coagulase positive, and detection of spp. The persistence of AM and M&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 10 CFU/g) followed by flaxseed flour (1.1 x 10 CFU/g) while the lowest level was found in chia (2.9 x 10 CFU/g). This seed also presented the lowest average values of filamentous fungi (9.8 x 10 CFU/g), whereas sunflower seeds had the highest levels (1.7 x 10 CFU/g). Flaxseed flour had the highest yeast counts (1.5 x 10 CFU/g). Although some samples had high levels of AM and fungi, β-GP and were not detected, therefore, they complied with the microbiological criteria of the European Union. The organic flaxseed contained higher numbers of AM and M&Y than the non-organic ones (p < 0.05). In addition, the storage of flaxseed at 20 °C resulted in changes of AM and M&Y, showing that these populations were able to remain viable after eleven months (AM Log 5.4-Log 5.6; M&Y Log 2.8-Log 4.1). The results obtained in the present study, namely those high levels of AM and fungi (>10 and 10 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.