Abstract

Introduction. Medicinal herbs are susceptible to microbial contamination which can have profound effects on the consumer’s health. Our study aimed to evaluate microbial contamination of common medicinal herbs in Ahvaz.
Study objects and methods. We collected 80 samples of traditional and industrial medicinal plants from the supply market, namely valeriana, fennel, licorice, and shirazi thyme. The reference method was used to determine microbial indices such as the total count of microorganisms, yeast and mold, Bacillus cereus, coliforms, and Escherichia coli.
Results and discussion. We found that the total microbial count, yeast and mold, B. cereus, and coliform contamination accounted for 45, 77, 55, and 55% of the total samples, respectively, exceeding the allowed limits. There was a significant difference between the industrial and traditional samples in fungal and coliform contamination, with the traditional samples being more highly contaminated. However, no significant difference was observed between them in total count and B. cereus contamination. E. coli contamination was detected in 31.2% of the samples, mostly in traditional. Total microbial count and yeast and mold contamination were highest among valeriana plants. Fennel showed the highest B. cereus and coliform contamination. The lowest contamination was observed in licorice.
Conclusion. The results showed that a considerable percentage of the medicinal herbs under study were contaminated at levels exceeding the standard limits. Plants could be contaminated during harvesting, processing or storage. Finally, different species of plants have different antimicrobial activities that affect their microbial contamination.

Keywords

Microbiology, microbial contamination, quality control, medicinal herbs, total microbial count

REFERENCES

1. Chan K. Some aspects of toxic contaminants in herbal medicines. Chemosphere. 2003;52(9):1361–1371. DOI: https://doi.org/10.1016/S0045-6535(03)00471-5.
2. Kosalec I, Cvek J, Tomic S. Contaminants of medicinal herbs and herbal products. Archives of Industrial Hygiene and Toxicology. 2009;60(4):485–501. DOI: https://doi.org/10.2478/10004-1254-60-2009-2005.
3. Kneifel W, Czech E, Kopp B. Microbial contamination of medicinal plants – A review. Planta Medica. 2002;68(1): 5–15. DOI: https://doi.org/10.1055/s-2002-20060.
4. Khan RS, Grigor J, Winger R, Win A. Functional food product development – Opportunities and challenges for food manufacturers. Trends in Food Science and Technology. 2013;30(1):27–37. DOI: https://doi.org/10.1016/j.tifs.2012.11.004.
5. Hashem M, Alamri S. Contamination of common spices in Saudi Arabia markets with potential mycotoxin-producing fungi. Saudi Journal of Biological Sciences. 2010;17(2):167–175. DOI: https://doi.org/10.1016/j.sjbs.2010.02.011.
6. WHO Monographs on Medicinal Plants Commonly Used in the Newly Independent States (NIS). Geneva: World Health Organization; 2010. 450 p.
7. Lee LH, Wu M, Peri A, Chu T. Method evaluations for Escherichia coli and coliforms detection in northern New Jersey water bodies. Journal of BioSciences. 2014;3(1):40–45. DOI: https://doi.org/10.5176/2251-3140_3.1.49.
8. Xu ZB, Xie JH, Liu JY, Ji LL, Soteyome T, Peters BM, et al. Whole-genome resequencing of Bacillus cereus and expression of genes functioning in sodium chloride stress. Microbial Pathogenesis. 2017;104:248–253. DOI: https://doi.org/10.1016/j.micpath.2017.01.040.
9. Purnima, Meenakshi B, Preeti K. A review article on phytochemistry and pharmacological profiles of Nardostachys jatamansi DC-medicinal herb. Journal of Pharmacognosy and Phytochemistry. 2015;3(5):102–106.
10. Badgujar SB, Patel VV, Bandivdekar AH. Foeniculum vulgare Mill: A review of its botany, phytochemistry, pharmacology, contemporary application, and toxicology. Biomed Research International. 2014. DOI: https://doi.org/10.1155/2014/842674.
11. Parvaiz M, Hussain K, Khalid S, Hussnain N, Iram N, Hussain Z, et al. A review: medicinal importance of Glycyrrhiza glabra L. (Fabaceae Family). Global Journal of Pharmacology. 2014;8(1):8–13. DOI: https://doi.org/10.5829/idosi.gjp.2014.8.1.81179.
12. Saleem M, Nazli R, Afza N, Sami A, Ali MS. Biological significance of essential oil of Zataria multiflora boiss. Natural Product Research. 2004;18(6):493–497. DOI: https://doi.org/10.1080/14786410310001608064.
13. Ghisleni DD, Bragaa MD, Kikuchia IS, Brasoveanu M, Nemtanu MR, Dua K, et al. The microbial quality aspects and decontamination approaches for the herbal medicinal plants and products: An in-depth review. Current Pharmaceutical Design. 2016;22(27):4264–4287. DOI: https://doi.org/10.2174/1381612822666160623070829.
14. Sahil K, Sudeep B, Akanksha M. Standardization of medicinal plant materials. International Journal of Research in Ayurveda and Pharmacy. 2011;2(4):1100–1109.
15. Schweiggert U, Carle R, Schieber A. Conventional and alternative processes for spice production – a review. Trends in Food Science and Technology. 2007;18(5):260–268. DOI: https://doi.org/10.1016/j.tifs.2007.01.005.
16. Banerjee M, Sarkar PK. Microbiological quality of some retail spices in India. Food Research International. 2003;36(5):469–474. DOI: https://doi.org/10.1016/S0963-9969(02)00194-1.
17. Abba D, Inabo HI, Yakubu SE, Olonitola OS. Contamination of herbal medicinal products marketed in Kaduna metropolis with selected pathogenic bacteria. African Journal of Traditional Complementary and Alternative Medicines. 2009;6(1):70–77. DOI: https://doi.org/10.4314/ajtcam.v6i1.57076.
18. Abou Donia MA. Microbiological quality and aflatoxinogenesis of Egyptian spices and medicinal plants. Global Veterinaria. 2008;2(4):175–181.
19. Vali Asill R, Azizi M, Bahreini M, Arouie H. The survey of microbial quality of the dry sample, extract and brewing of some medicinal plants. Notulae Scientica Biologicae. 2014;6(4):478–482. DOI: https://doi.org/10.1583/nsb649286.
20. Alwakeel S. Microbial and heavy metals contamination of herbal medicines. Research Journal of Microbiology. 2008;3(12):683–691. DOI: https://doi.org/10.3923/jm.2008.683.691.
21. Martins HM, Martins ML, Dias MI, Bernardo F. Evaluation of microbiological quality of medicinal plants used in natural infusions. International Journal of Food Microbiology. 2001;68(1–2):149–153. DOI: https://doi.org/10.1016/S0168-1605(01)00480-9.
22. Sagdic O, Ozcan M. Antibacterial activity of Turkish spice hydrosols. Food Control. 2003;14(3):141–143. DOI: https://doi.org/10.1016/S0956-7135(02)00057-9.
23. Lang GR, Buchbauer G. A review on recent research results (2008–2010) on essential oils as antimicrobials and antifungals. A review. Flavour and Fragrance Journal. 2012;27(1):13–39. DOI: https://doi.org/10.1002/ffj.2082.
24. Weightman RM. Heavy metal and microbial contamination of valerian (Valeriana officinalis L.) roots gown in soil treated with sewage sludge. Journal of Herbs, Spices & Medicinal Plants. 2007;12(3):77–88. DOI: https://doi.org/10.1300/J044v12n03_06.
25. Fatima A, Gupta VK, Luqman S, Negi AS, Kumar JK, Shanker K, et al. Antifungal activity of Glycyrrhiza glabra extracts and its active constituent glabridin. Phytotherapy Research. 2009;23(8):1190–1193. DOI: https://doi.org/10.1002/ptr.2726.
26. Nitalikar MM, Munde KC, Dhore BV, Shikalgar SN. Studies of antibacterial activities of Glycyrrhiza glabra root extract. International Journal of PharmTech Research. 2010;2(1):899–901.
27. Walter C, Shinwari ZK, Afzal I, Malik RN. Antibacterial activity in herbal products used in Pakistan. Pakistan Journal of Botany. 2011;43:155–162.
28. Ates DA, Erdogrul OT. Antimicrobial activities of various medicinal and commercial plant extracts. Turkish Journal of Biology. 2003;27(3):157–162.
29. WHO guidelines on safety monitoring of herbal medicines in pharmacovigilance systems. Geneva: World Health Organization; 2004. 82 p.