Aflatoxin M1 In Cheese Samples Research Articles

Combination of solvent extraction with deep eutectic solvent based dispersive liquid-liquid microextraction for the analysis of aflatoxin M1 in cheese samples using response surface methodology optimization.

A new extraction procedure based on combination of a solvent extraction and deep eutectic solvent based dispersive liquid-liquid microextraction has been introduced for the extraction of aflatoxin M1 from cheese samples. In this method, acetonitrile, deionized water, and n-hexane are added onto the sample and vortexed. Owning to different affinities of the substances in cheese toward the mentioned solvents, an efficient and selective extraction of the analyte is done in the acetonitrile phase. After centrifugation, the acetonitrile phase is removed and mixed with a new hydrophobic deep eutectic solvent prepared from N,N-diethanol ammonium chloride and carvacrol as an extraction solvent. The mixture is injected into deionized water, and a cloudy solution is obtained. Eventually, an aliquot of the organic phase is injected into high-performance liquid chromatography-fluorescence detection. After optimizing the effective parameters with the response surface methodology and a quadratic model, limits of detection and quantification were 0.74 and 2.56ng/kg, respectively. The obtained extraction recovery and enrichment factor were 94% and 94, respectively. Also, intra- (n=6) and interday (n=4) precisions were less than or equal to 8.6% at a concentration of 5ng/kg. The suggested method was applied to determine aflatoxin M1 in different cheese samples.

Survey of the occurrence of aflatoxin M1 in dairy products marketed in Iran

In this survey the incidence of aflatoxin M1 (AFM1) contamination in some dairy products collected from the Iran market was investigated using enzyme-linked immunosorbent assay (ELISA) technique. From February 2011 to February 2012, a total of 200 samples composed of yoghurt (60 samples), cheese (80 samples), and ice-cream (60 samples) showed that 75.5% of the tested samples were contaminated with various levels of AFM1 ranging from 14.3 to 572.1 ng/L. AFM1 was detected in 48 (80.0%) yoghurt samples (ranging from 19.7 to 319.4 ng/L), in 69 (86.3%) chesses samples (ranging from 14.3 to 572.1 ng/L) and in 34 (56.7%) of ice cream samples ranging from (ranging from14.9 to 147.4 ng/L). Eleven of cheese samples (13.8%) and three of yoghurt samples (5.0%) were higher that maximum tolerance limit accepted by European union/codex Alimentarius (250 ng/L). It was concluded that widespread occurrence of AFM1 in cheese samples was considered to be possible hazards for public health especially for children. This study suggests a regular monitoring of AFM1 in milk and milk products in the country.

Occurrence of aflatoxin M1 in white cheese samples from Tehran, Iran

This study was undertaken to determine the occurrence of aflatoxin M1 (AFM1) in 50 white cheese samples from 2 dairy factories in summer 2008 and winter 2009. Enzyme-linked immunosorbent assay (ELISA) method was used for analysis of the samples. Aflatoxin M1 was found in 60% of the cheese samples, ranging from 40.9 to 374 ng/kg. Toxin levels in 6% of the samples exceeded the Iranian national standard limit i.e. 200 ng/kg. Considering seasonal variability, mean concentration of AFM1 in the samples collected in winter was significantly (P < 0.03) higher than those collected in summer. Therefore, high occurrence of AFM1 in cheese samples could be a potential hazard for public health.

Occurrence of aflatoxin M1 in traditional cheese consumed in Esfahan, Iran

Aflatoxin M1 (AFM1) was determined by enzyme linked immunosorbent assay in 88 samples of traditional cheese consumed in Esfahan city of Iran. In 47 of 88 samples (53.4%), the presence of AFM1 was detected in concentrations between 82 ng/kg and 1254 ng/kg. The mean level of AFM1 of positive samples was 412 ng/kg. AFM1 in 28 (31.8%) samples was higher than the maximum tolerance limit (250 ng/kg) accepted by some countries. Statistical analysis showed that there were no significant differences (P&gt;0.05) between the mean concentrations of AFM1 in cheese samples of spring, summer, autumn and winter. However, the mean concentration of AFM1 in cheese samples from spring and summer was significantly lower than autumn and winter (P=0.05). It can be concluded that the high occurrence of AFM1 in cheese is probably due to the presence of aflatoxin in the feed and cheese milk. This condition should be considered as a probable hazard for human health.

Flow Injection Monitoring of Aflatoxin M1 in Cheese Using Filter-Supported Bilayer Lipid Membranes with Incorporated DNA

This work describes a technique for the rapid and sensitive electrochemical flow injection monitoring of aflatoxin M1 (AFM1) in cheese samples. Stabilized filter-supported bilayer lipid membranes (BLMs) were used as detectors Single stranded DNA oligomers terminated with alkyl chains (dT20–C16) were incorporated into the membranes to control surface electrostatic properties. The incorporation of dT20–C16 in BLMs lowered the detection limit for the detection of this toxin by one to four orders of magnitude as compared with the detection limit obtained in the absence of DNA. Therefore, it is now possible to continuously monitor this toxin at concentrations that approached those that could be of interest as set by the U.S. Food and Drug Administration and most European countries. The work described herein takes a significant step towards development of a detector of greater practical potential by demonstrating that the incorporation of C16-ssDNA into lipid membranes results in a combination of properties that provides for a much more sensitive and robust detection system. Injections of AFM1 were made into flowing streams of a 0.1 M KCl electrolyte solution, and a transient current signal with duration of seconds reproducibly appeared in about 12 s after exposure of the detector element to the toxin. The magnitude of this signal was linearly related to the concentration of AFM1 with detection limits at subnanomolar level. The effect of interferents such as proteins and lipids was investigated. It was determined that interferences from proteins could be eliminated by adjustment of the flow rate of the carrier electrolyte solution. The technique was applied for the rapid flow injection determination of aflatoxin M1 in cheese samples. AFM1 could be determined in continuous flowing systems with a rate of at least 4 samples min–1. Repetitive cycles of injection of AFM1 have shown no signal degradation during each cycle for experiments that attempted over 30 cycles of detection.