Human Food Samples Research Articles

Molecular Recognition of Imidazole-Based Drug Molecules by Cobalt(III)- and Zinc(II)-Coproporphyrins in Aqueous Media.

The methods of 1H NMR, spectrophotometric titration, mass spectrometry and elemental analysis are applied to determine the selective binding ability of Co(III)- and Zn(II)-coproporphyrins I towards a series of imidazole-based drug molecules with a wide spectrum of pharmacological activity (metronidazole, histamine, histidine, tinidazole, mercazolil, and pilocarpine) in phosphate buffer (pH 7.4) simulating the blood plasma environment. It is shown that in aqueous buffer media, Co(III)-coproporphyrin I, unlike Zn(II)-coproporphyrin I, binds two imidazole derivatives, and the stability of mono-axial Co-coproporphyrin imidazole complexes is two to three orders of magnitude higher than that of similar complexes of Zn-coproporphyrin I. The studied porphyrinates are found to have the highest binding ability to histamine and histidine due to the formation of two additional hydrogen bonds between the carboxyl groups of the porphyrinate side chains and the binding sites of the ligands in the case of histidine and a hydrogen bond between the amino group of the ligand and the carbonyl oxygen atom of the carboxyl group of the porphyrinate in the case of histamine. The structures of the resulting complexes are optimized by DFT quantum chemical calculations. The results of these studies may be of use in the design of biosensors, including those for the detection, control and verification of various veterinary drug residues in human food samples.

Mycotoxin hazards in the Kenyan food and feed market - A retrospective study

Mycotoxins are toxic fungal metabolites naturally found in food and feed as contaminants. Animal feed and human food samples (n=1818) from three major Kenyan laboratories were categorized as compliant and non-compliant according to Kenya, America (USA) and Europe (EU) mycotoxin regulatory limits. Quantitative risk assessment of dietary aflatoxin intake in maize, wheat, peanut and dairy products in relation to human hepatocellular carcinoma was carried out employing deterministic approach. Non-compliant samples’ proportions were calculated, and logistic regression and chi-square test used to compare different commodities. Animal feed were least compliant, with 64% and 39% having total aflatoxin (AFT) levels above Kenya and USA standards, respectively. Peanuts were the most non-compliant food, with 61% and 47% samples failing Kenya and USA AFT standards respectively, while wheat was least compliant (84%) according to EU threshold for AFT. Half of baby food sampled had AFT level above Kenya and EU standards. High non-compliance rate with Kenya, USA and EU regulatory thresholds with respect to seven different mycotoxins (summarized as “mycotoxins”), and also AFT and aflatoxin M1 alone in edible materials is reported. Significant non-compliance is reported for compound animal feed, peanuts, wheat, baby food, feed ingredients, herbal healthy drink, maize and fodder feed in that order. High levels of aflatoxin residues in animal feed and human food was also observed. Lifetime human consumption of wheat and maize leads to high additional risk for primary liver cancer, human hepatocellular carcinoma (HCC) associated with dietary aflatoxin, wheat and its products causing the highest disease burden. Subsequent implications and limitations of current food safety standards are discussed. Humans and animals in Kenya appear to be chronically exposed to mycotoxin hazards: this calls for surveillance and risk management. There is urgent need for enhanced and consistent surveillance of the dietary mycotoxin hazards observed in this study employing representative sampling plans. Regulation and future research need to focus on reliable analysis techniques, collection of data on toxicological effects of mycotoxins and food consumption pattern, and regulatory limits accordingly set and compliance enforced to protect vulnerable groups such as paediatric, geriatric and sick members of the society to reduce cancer burden in Kenya. Key words: Mycotoxins, food, feed, risk analysis, human hepatocellular carcinoma, Kenya

US Food and Drug Administration regulatory pesticide residue monitoring of human foods: 2009-2017

ABSTRACT Pesticides such as insecticides, fungicides, and herbicides can protect crops from insects, fungi, weeds, and other pests but must be applied following label instructions so that the pesticide residues in human and animal foods do not exceed maximum residue limits (MRLs, known in the US as pesticide tolerances). The US Food and Drug Administration (FDA) collects and tests foods for pesticide residues to enforce compliance with tolerances and publishes annual reports on pesticide testing results. In this study, results for over 56,000 human food samples collected and analysed under the FDA pesticide residue monitoring programme between fiscal years (FY) 2009 to 2017 were reviewed to identify trends not apparent in annual reports. The overwhelming majority of these samples, 98.0% of domestic and 90.9% of import human foods, were compliant with federal standards. Although herbicides may be more widely used, the 10 most frequently detected residues were insecticides and fungicides. On a yearly basis, the violation rate for imported samples is 3–5 times higher than the rate for domestic samples. The import violation rate increased over time, as did the number of residues detected. Targeted sampling of foods with higher commodity-specific violation rates appears to be a major contributor to the increased violation rate. Mismatches between US tolerances and international MRLs can lead to violations; this was especially marked for rice. Overall, the majority of violations are due to residues of pesticides not authorised for use in the US (lack of tolerances). While DDT continues to persist in the environment and was found in 2.2% of domestic samples and 0.6% of imported samples, 42.3% of DDT-positive samples were below the limit of quantitation. The trends and analyses identified in this paper may help FDA plan future sampling and continue to protect the food supply.

Survival mechanisms and culturability of Campylobacter jejuni under stress conditions

Culture-based isolation and enumeration of bacterial human pathogens from environmental and human food samples has significant limitations.Many pathogens enter a viable but non-culturable(VBNC) state in response to stress, and cannot be detected via culturing methods. Favourable growth conditions with a source of energy and an ideal stoichiometric ratio of carbon to inorganic elements can reverse this VBNC state. This review will focus on the bacterium Campylobacter jejuni which is a leading cause of food borne illness in the developed world. C. jejuni can enter a VBNC state in response to extremes in: pH, moisture content, temperature,nutrient content and salinity. Once in a VBNC state,the organism must maintain an energy balance from substrate oxidation through respiration to grow,divide and remain viable. The goal of this review isa greater understanding of how abiotic stress and thermodynamics influence the viability of C. jejuni.

Mercury Determination in Human Food Samples

Mercury Determination in Human Food Samples

Mercury determination in human food samples

Mercury determination in human food samples