| Literature DB >> 22942705 |
Muhammad Mushtaq1, Bushra Sultana1, Farooq Anwar2, Muhammad Zargham Khan3, Muhammad Ashrafuzzaman4.
Abstract
A total of 125 (ready to eat) processed food samples (70 intended for infant and 55 for adult intake) belonging to 20 different food categories were analyzed for aflatoxins contamination using Reverse Phase High Performance Liquid Chromatography (RP-HPLC) with fluorescent detection. A solvent mixture of acetonitrile-water was used for the extraction followed by immunoaffinity clean-up to enhance sensitivity of the method. The limit of detection (LOD) (0.01-0.02 ng·g(-1)) and limit of quantification (LOQ) (0.02 ng·g(-1)) was established for aflatoxins based on signal to noise ratio of 3:1 and 10:1, respectively. Of the processed food samples tested, 38% were contaminated with four types of aflatoxins, i.e., AFB1 (0.02-1.24 μg·kg(-1)), AFB2 (0.02-0.37 μg·kg(-1)), AFG1 (0.25-2.7 μg·kg(-1)) and AFG2 (0.21-1.3 μg·kg(-1)). In addition, the results showed that 21% of the processed foods intended for infants contained AFB1 levels higher than the European Union permissible limits (0.1 μg·kg(-1)), while all of those intended for adult consumption had aflatoxin contamination levels within the permitted limits.Entities:
Keywords: HPLC; aflatoxins contamination; cereals based products; effective recovery; immunoaffinity clean-up
Mesh:
Substances:
Year: 2012 PMID: 22942705 PMCID: PMC3430236 DOI: 10.3390/ijms13078324
Source DB: PubMed Journal: Int J Mol Sci ISSN: 1422-0067 Impact factor: 6.208
Figure 1High Performance Liquid Chromatography (HPLC) Chromatogram of 5 ppb standard mixture of four aflatoxins.
Figure 2HPLC chromatogram showing the repeatability and reproducibility of AFGl, AFBl, AFGl and AFB2 standards.
Repeatability, reproducibility and accuracy of HPLC method used for aflatoxin determination.
| Aflatoxin | LOD | LOQ | Calibration Curve | Recovery (%) | Mean (μg kg−1) ± RSD (%) | |
|---|---|---|---|---|---|---|
| AFB1 | 0.02 | 0.05 | y = 68,983x + 34,942 | 0.9997 | 97.6 | 125.3 ± 9.12 |
| AFB2 | 0.01 | 0.02 | y = 104,767x – 6,094 | 0.9995 | 91.2 | 15.3 ± 2.01 |
| AFG1 | 0.02 | 0.05 | y = 32,045x + 2,780 | 0.9996 | 97.6 | 15.3 ± 1.44 |
| AFG2 | 0.01 | 0.02 | y = 61,801x − 85.618 | 0.9991 | 91.2 | 6.3 ± 3.42 |
Limit of detection;
Limit of quantification;
Accuracy was determined by the determination of the recoveries of aflatoxins. By spiking 125.5 μg kg−1 aflatoxin B1, 15.3 μg kg−1 aflatoxin G1 and B2 and 6.3 μg kg−1 G2 to the samples (uninfected ground and tree nuts);
Replicate analysis of each spiked sample was used to determine the accuracy, expressed as mean (μg kg−1) ± relative standard deviation (%).
Level of AFB1 and total aflatoxin (AFT) in processed food intended for infants.
| Sample Typed | Number of Samples | Positive Samples | Samples Having AFB1 > 0.1 μg kg−1 | Samples Having AFB1 < 0.1 μg kg−1 | Total Aflatoxin (mean ± SD) mg kg−1 |
|---|---|---|---|---|---|
| Cerelac | 10 | 4 (40) | 2(20) | 2 (20) | 0.052 ± 0.020–0.19 ± 0.06 |
| Powder Milk | 10 | 3 (33) | 2 (20) | 1 (13) | 0.030 ± 0.001–0.36 ± 0.07 |
| Noodles | 10 | 5 (50) | 4(40) | 1 (10) | 0.025 ± 0.001–0.40 ± 0.09 |
| Cream of rice | 5 | 1 (20) | - | 1(20) | 0.025 ± 0.001–0.16 ± 0.05 |
| Biscuits | 10 | 3 (20) | 1 (32) | 2 (68) | (0.041 ± 0.02)–(2.48 ± 0.38) |
| Corn Products | 10 | 7 (70) | 5 (50) | 2 (20) | (0.050 ± 0.020)–(3.74 ± 0.62) |
| Oatmeal | 5 | 1 (20) | - | 1 (20) | (0.02 ± 0.001)–(0.025 ± 0.001) |
| Potato sticks | 5 | 1 (20) | 1 (50) | 1 (50) | (0.026 ± 0.001)–(2.96 ± 1.35) |
| Wheat Porridge | 5 | - | - | - | - |
|
| |||||
| Total | 70 | 25 (35) | 15 (21) | 10 (14) | - |
Figure 3Typical chromatogram of uninfected wheat porridge processed food (sample shows undetectable amounts of aflatoxin).
Incidence level and range of different types of aflatoxins in processed foods.
| Sample Type | Incidence (%) | Aflatoxin Range (μg kg−1) | |||||
|---|---|---|---|---|---|---|---|
|
| |||||||
| AFB1 | AFB2 | AFG1 | AFG2 | Total aflatoxin (AFT) | |||
| Chines fried rice | 5 | 1 (20) | ND | ND | 0.025 | 1.3 | (0.03 ± 0.001)–(1.30 ± 0.002) |
| Bread slices | 3 | 1 (33.3) | 0.02–0.06 | BD | 0.06 | ND | (0.1 ± 0.003)–(0.26 ± 0.004) |
| Sohn Halwa | 3 | 1 (33.3) | BD | ND | ND | ND | (0.04 ± 0.001)–(0.16 ± 0.003) |
| Chapati local wheat cleaned with air | 3 | 3 (100.0) | 0.02–0.27 | ND | ND | 0.03–0.94 | (0.05 ± 0.002)–(1.21 ± 0.04) |
| Chapati local wheat cleaned with water | 3 | 0 (0) | ND | ND | ND | ND | ND |
| Chapati (commercial flour) | 3 | 2 (66.7) | BD | 0.025 | 1.36 | 0.03 | (0.07 ± 0.003)–(1.36 ± 0.06) |
| Every Day Milk | 9 | 2 (22) | 0.0474 | ND | 0.141 | 0.084 | (0.05 ± 0.002)–(0.27 ± 0.005) |
| gram flour | 5 | 3 (60) | 0.32–1.02 | 0.12 | 0.58 | 0.34 | (0.8 ± 0.06)–(2.1 ± 0.01) |
| Peanuts (nimko) | 5 | 3 (60) | 0.21–1.24 | 0.13032 | ND | 1.741 | (0.27 ± 0.003)–(2.08 ± 0.01) |
| Lays | 3 | 1 (60) | BD | ND | 0.57 | ND | 0.57 |
| Bread slices | 5 | 3 (20) | 0.021 | ND | 0.06 | ND | 0.85 |
| Soji Halwa | 3 | 0 (0) | ND | ND | ND | ND | ND |
| Barian | 5 | 1 (20) | 0.07 | 0 | 0.25 | 0.15 | (0.03 ± 0.001)–(0.48 ± 0.006) |
| Total | 55 | 22 (40) | |||||
Figure 4Chromatogram showing high level of AFB1 in gram flour.
Figure 5Typical HPLC chromatogram of aflatoxins in Nimko (peanut product).