Detection of fungal and bacterial contamination of hazelnut and determination of aflatoxin B by HPLC method in Isfahan, Iran

Document Type : Original Articles

Authors

1 Department of Microbiology, Falavarjan Branch, Islamic Azad University, Isfahan, Iran

2 Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

3 Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran

10.18502/cmm.7.4.8404

Abstract

Background and Purpose: Due to the fact that fungal species such as Aspergillus flavus and Aspergillus parasiticus produce carcinogenic and mutagenic aflatoxins and have the potential to produce fungal secondary metabolites, fungal contamination should be avoided. This study was conducted using the HPLC method and was aimed at examining the fungal contamination of Isfahan hazelnuts in order to identify the presence of Aflatoxins.
Materials and Methods: One hundred samples of hazelnuts were randomly collected from supermarkets in Isfahan. The samples were then cultured on Sabouraud dextrose agar (SDA) media and analyzed to determine fungal contaminations. The aflatoxin analysis was carried out using the HPLC method.
Results: It was discovered that nine genera of fungi, namely Aspergillus, Penicillium , Rhizopus, Ulocladium, Alternaria, Drechselera, Trichothecium, Scopulariopsis, and Mucor were identified in 78% of the samples. Samples contaminated with Aspergillus flavus (22 samples) were studied to determine the presence of aflatoxin. The results showed that 16 (72.72%) of the samples were contaminated with AFB1, AFB2 and AFG2 and the mean concentrations were 0.926, 0.563 and 0.155ng/g, respectively.
Conclusions: Some parameters that affect mycotoxin production are temperature, food substrate, strain of the mold and other environmental factors. Due to the toxigenic quality of some of these fungi and their hazard to human health, it is crucial that fungal contamination and aflatoxin identification tests are carried out before certain products are made available to the mass market.

Highlights

 1. Dasan BG, Boyaci IH, Mutlu M. Nonthermal plasma treatment of Aspergillus spp. spores on hazelnuts in an atmospheric
pressure fluidized bed plasma system: Impact of process
parameters and surveillance of the residual viability of spores. J
Food Eng. 2017; 196:139-49.
2. Moslehi Z, Mohammadi Nafchi A, Moslehi M, Jafarzadeh S.
Aflatoxin, microbial contamination, sensory attributes, and
morphological analysis of pistachio nut coated with
methylcellulose. Food Sci Nutr. 2021; 9(6).
3. Zhang G, Hu L, Melka D, Wang H, Laasri A, Brown EW, et al.
Prevalence of Salmonella in cashews, hazelnuts, macadamia
nuts, pecans, pine nuts, and walnuts in the United States. J Food
Prot. 2017; 80(3):459-66.
4. Güler S, Bostan S, Çon A, Turanlı F, editors. Effect of gamma
irradiation on microbiological and pest load of natural hazelnut
kernels. IX International Congress on Hazelnut 1226. 2017;
6(2): 95-100.
5. Frisvad JC, Thrane U, Samson RA. Mycotoxin producers.
Mycology Series. 2007; 25:135.
6. Katsurayama AM, Martins LM, Iamanaka BT, Fungaro MHP,
Silva JJ, Frisvad JC, et al. Occurrence of
Aspergillus section
Flavi and aflatoxins in Brazilian rice: From field to marketInt. J
Food Microbiol. 2018; 266:213-21.
7. Sarma UP, Bhetaria PJ, Devi P, Varma A. Aflatoxins: implications
on health. Indian J Clin Biochem. 2017; 32(2):124-33.
8. Kabak B. Aflatoxins in hazelnuts and dried figs: Occurrence and
exposure assessment. Food Chemistry. 2016; 211:8-16.
9. Filazi A, Sireli UT. Occurrence of aflatoxins in food. Aflatoxins:
Recent Advances and Future Prospects InTech. 2013: 143-70.
10. Eskola M, Kos G, Elliott CT, Hajšlová J, Mayar S, Krska R, et
al. Worldwide contamination of food-crops with mycotoxins:
Validity of the widely cited ‘FAO estimate’of 25%. Crit Rev
Food. 2020; 60(16):2773-89.
11. Azizkhani M, Jafari F, Haghighi P, Dehghan M. Evaluating
Contamination Level of Raw and Roasted Nuts Distributed in
Commercial Markets in Mazandaran Province, Iran. Iran J Vet
Surg.2020; 14(2): 167-76.
12. Khosravi AR, Shokri H, Ziglari T. Evaluation of fungal flora in
some important nut products (pistachio, peanut, hazelnut and
almond) in Tehran, Iran. Pak J Nutr. 2007; 6(5):460-2.
13. Beck JJ, Mahoney NE, Cook D, Gee WS. Generation of the
volatile spiroketals conophthorin and chalcogran by fungal
spores on polyunsaturated fatty acids common to almonds and
pistachios. Journal of Agricultural and Food Chemistry.
2012;60(48):11869-76.
14. Ortega-Beltran A, Moral J, Puckett RD, Morgan DP, Cotty PJ,
Michailides TJ. Fungal communities associated with almond
throughout crop development: Implications for aflatoxin biocontrol
management in California. PLoS One. 2018;13(6):e0199127.
15. Hocking AD, Pitt JI, Samson RA, Thrane U. Recommended
methods for food mycology. Advances in food mycology. 2006;
571: 343–348.
16. Ruchel R, SchaffrinskiM. Versatile fluorescent staining of fungi
in clinical specimens by using the optical brightener
Blankophor. J Clin Microbiol. 1999; 37(8):2694-2696.
17. Pour RS, Rasti M, Zighamian H, Garmakhani AD. Occurrence
of aflatoxins in pistachio nuts in Esfahan Province of Iran. J
Food Saf. 2010; 30(2):330-40.
18. Imani Nejad M, Farahani AD. Aflatoxin in raw walnut kernels
marketed in Tehran, Iran. Food Addit Contam. 2012; 5(1):8-10.
19. Scussel VM. Aflatoxin and food safety: Recent south American
perspectives. J Toxicol. .2004; 23(2-3):179-216.
20. Hedayati MT, Kaboli S, Mayahi S. Mycoflora of pistachio and
peanut kernels from Sari, IranJundishapur J Microbiol. 2010:
3(3); 114-120.
21. Kabak B. Aflatoxins in hazelnuts and dried figs: Occurrence and
exposure assessment. Food Chem. 2016; 211:8-16.
22. Wang J, Liu XM. Contamination of aflatoxins in different kinds
of foods in China. Biomed Environ. 2007; 20(6):483-7.
23. Sobolev VS. Simple, rapid, and inexpensive cleanup method for
quantitation of aflatoxins in important agricultural products by
HPLC. J Agric Food Chem. 2007; 55(6):2136-41
 

Keywords