Determination of aflatoxins in coffee by means of ultra-high performance liquid chromatography-fluorescence detector and fungi isolation

Figures & data

Figure 1. (a) Chemical structure of Aflatoxins of B family (B1 and B2) and G family (G1 and G2) [5]. The moiety in blue or red Circle shows the difference between the two groups, and (b) Chemical structure of major functional moieties of Aflatoxins [57].

Table 1. Analytical and performance characteristics of the aflatoxins determination method.

Analytes	Expected (μg/kg)	Run 1 (μg/kg)	Run 2 (μg/kg)	Run 3 (μg/kg)	Run 4 (μg/kg)	Run 5 (μg/kg)	Run 6 (μg/kg)	Mean (μg/kg)	Recovery (%)	Standard Deviation (SD)	RSD (%)	LOD (3*SD)
Aflatoxins G1	2.00	1.61	1.45	1.59	1.56	1.57	1.56	1.55	77.5	0.06	3.54	0.17
Aflatoxins B1	2.00	1.53	1.40	1.51	1.49	1.50	1.48	1.49	74.5	0.05	3.15	0.14
Aflatoxins G2	2.00	1.57	1.53	1.60	1.63	1.64	1.60	1.60	80.0	0.04	2.59	0.12
Aflatoxins B2	2.00	1.52	1.45	1.53	1.52	1.53	1.49	1.51	75.5	0.03	2.04	0.09

Figure 2. UHPLC-FLD chromatogram of sample A (4.27 x 10⁻¹μg/kg aflatoxin G1 (AFLA.G1)).

Figure 3. Pictures of microorganisms isolated from the studied samples of coffee. (a) colonies of Aspergillus niger, (b) Mucor sp. Fusarium and yeast sp. 2., (c) Fusarium and yeast sp. 1 colonies, (d) Colonies of Aspergillus niger group and Fusarium sp.

Table 2. List of microorganisms (Bacteria and Fungi) isolated from different coffee samples collected from the local Doha market.

Sample Label	Description	Aflatoxin detection (Chemical detection)	Microorganism (microbiological detection)
A	Packed roasted beans – 1	+ (AFG1)	ND
B	Packed roasted beans – 2	ND	Yeast sp. 1
C	Packed roasted powder with cardamom – 1	ND	Yeast sp. 1
D	Packed roasted powder with cardamom – 2	ND	Aspergillus niger Yeast sp. 2
E	Packed roasted powder with cardamom – 3	ND	Aspergillus sp. Yeast sp. 2
F	Packed roasted powder – 1	ND	Yeast sp. 2
G	Packed roasted powder −2	ND	ND
H	Packed roasted powder – 3	ND	Yeast sp. 1
I	Unpacked raw beans – 1	ND	Aspergillus niger Mucor sp.- Bacillus sp. – Fusarium sp.
J	Unpacked raw beans – 2	ND	Aspergillus niger Rhizopus sp. Yeast sp. 1
K	Unpacked raw beans – 3	ND	Aspergillus niger
O	Unpacked roasted beans – 1	+ (AFG1)	Aspergillus niger
P	Unpacked roasted beans – 2	ND	Aspergillus niger Bacillus sp.
R	Unpacked roasted beans – 3	ND	Aspergillus niger

ND: Not detected.

P. Li, Q. Zhou, T. Wang, H. Zhou, W. Zhang, X. Ding, Z. Zhang, P.-K. Chang and Q. Zhang, Toxins 8, 5 (2016). doi:10.3390/toxins8010005.

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