Microbial quality of edible seeds commercially available in southern Portugal

Daniela Silva; Patrícia Nunes; Jessie Melo; Célia Quintas; Daniela Silva; Patrícia Nunes; Jessie Melo; Célia Quintas

doi:10.3934/microbiol.2022004

AIMS Microbiology

2022, Volume 8, Issue 1: 42-52. doi: 10.3934/microbiol.2022004

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Microbial quality of edible seeds commercially available in southern Portugal

1.
Universidade do Algarve, Instituto Superior de Engenharia, Campus da Penha,8005-139, Faro Portugal
2.
MED, Mediterranean Institute for Agriculture, Environment and Development, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal

Received: 27 November 2021 Revised: 07 February 2022 Accepted: 09 February 2022 Published: 22 February 2022

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), Escherichia coli (β-glucuronidase positive) (β-GP E. coli), Staphylococcus coagulase positive, and detection of Salmonella 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 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 E. coli and Salmonella 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 (>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.
- Microbial quality,
- edible seeds,
- sesame,
- flaxseed,
- chia,
- pumpkin,
- sunflower
Citation: Daniela Silva, Patrícia Nunes, Jessie Melo, Célia Quintas. Microbial quality of edible seeds commercially available in southern Portugal[J]. AIMS Microbiology, 2022, 8(1): 42-52. doi: 10.3934/microbiol.2022004

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Abstract

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), Escherichia coli (β-glucuronidase positive) (β-GP E. coli), Staphylococcus coagulase positive, and detection of Salmonella 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 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 E. coli and Salmonella 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 (>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.

Acknowledgments

This study received Portuguese national funds from FCT-Foundation for Science and Technology through project MED/UIDB/05183/2020.

Conflict of interest

All authors declare no conflict of interest.

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