Diverging fates of cadmium and glyphosate during pasta cooking

Durum wheat cultivars with varying abilities to accumulate cadmium were grown and treated in the field with a glyphosate-containing herbicide at different stages of maturity to produce grain with higher and lower concentrations of cadmium (0.066-0.214 mg/kg) and glyphosate (0.474-0.874 mg/kg). The grain was milled, and fractions were analysed for cadmium and glyphosate. The highest concentrations for both cadmium and glyphosate were associated with bran and shorts, although the percentage of total cadmium mass in bran (23-25%) was less than glyphosate (38%). The preparation of dried pasta from semolina and flour milling fractions reduced concentrations by a factor of 1.8 for glyphosate and 1.4 for cadmium. Dried pasta was cooked and analysed along with the cooking water for cadmium and glyphosate at seven-time points from 0 to 15 min. Concentrations of glyphosate in cooked pasta decreased significantly with cooking time; no decrease was observed for cadmium concentrations. Analysis of cooking water demonstrated that glyphosate migrated from pasta to the cooking water. After 15 min of cooking, approximately 73% of the total glyphosate mass had transferred from pasta to cooking water. Over the same time period, only 5% of the total cadmium mass had transferred from pasta to cooking water.

Determination of Aminophosphonate Herbicides in Glutamate Loaded Spice Mix by LC-IDMS and Method Extension to Other Food Matrices

The accumulation of organophosphorus type herbicides has been observed worldwide in the environment (i.e. soil, water), together with their appearance in foods of plant origin. This paper reports a new liquid chromatography–isotope dilution–tandem mass spectrometric method (LC-IDMS) for the analysis of glufosinate (GLUF), glyphosate (GLY) and its main metabolite, aminomethylphosphonic acid (AMPA), in challenging food samples. Sample preparation is based on aqueous extraction with ethylenediaminetetraacetic acid solution, followed by solid-phase extraction (SPE) on mixed-mode cation exchange cartridges to remove matrix constituents before derivatization with 9-fluorenylmethoxycarbonyl chloride (FMOC-Cl). Derivatized samples were cleaned up on hydrophilic modified polymeric SPE cartridge. This two-step SPE supported sample preparation approach, and the LC-IDMS separation carried out in negative ionization mode resulted in fit-for-purpose recovery (81–118%) and precision (4–18%) in the validation of glutamate loaded spice mix, mushroom, maize and cherry samples. Amino acid content influencing FMOC derivatization efficiency was estimated with a HILIC-MS/MS setup. Multiple reaction monitoring (MRM) was assisted with high-resolution (QTOF) accurate mass data on the FMOC-derivatized GLUF, GLY and AMPA standards. The limit of quantification (LOQ) was 0.005 mg/kg for all the three analytes. The method was successfully applied on quality control samples (oat and arugula) with fit-for-purpose accuracy (99–120%) and on other nineteen real samples, where GLY and AMPA were detected in the range between 0.005 and 0.069 mg/kg.

Analysis of Microbiological and Chemical Hazards in Edible Insects Available to Canadian Consumers

ABSTRACT

Edible insects are a novel food in most countries; their popularity is growing because of their high-protein and low-fat content, ease of cultivation, and small environmental impact. To our knowledge, this is the first report that addresses both microbiological and chemical hazards in edible insects. Samples were collected from retail stores or purchase through e-commerce. A total of 51 samples of dried whole insects or insect powder were tested for Escherichia coli, which serves as an indicator of the overall sanitation conditions throughout the food production chain, and the bacterial pathogen Salmonella spp. Neither Salmonella spp. nor E. coli (>100 CFU/g) was found in the samples analyzed. A total of 43 samples of crickets (protein bars, powders, flour, and whole insects) and 4 samples of silkworm (whole insects) were analyzed for up to 511 pesticides. Of these, 39 samples contained up to four pesticides; 34 samples were compliant and 5 samples were noncompliant with Canadian regulations. Seven pesticide residues were detected, with glyphosate and its metabolite, aminomethylphosphonic acid, as the predominant residues. Nineteen of the samples tested for pesticides were also analyzed for arsenic, cadmium, mercury, and lead; there was insufficient material remaining to allow testing of pesticides and metals. The positive rates for arsenic, cadmium, lead, and mercury were 100, 79, 58, and 74%, respectively. The detected concentrations ranged from 0.030 to 0.34 mg/kg for arsenic, from 0.031 to 0.23 mg/kg for cadmium, 0.019 to 0.059 mg/kg for lead, and from 0.94 to 28 μg/kg for mercury. Based on the lack of detection of microbiological contamination, and the positive rates and levels of pesticides and metals observed in the products, Health Canada determined that all insect products analyzed were safe for human consumption. This is a limited study; the Canadian Food Inspection Agency will continue to monitor this novel food.

HIGHLIGHTS

Analysis of Glyphosate Residues in Foods from the Canadian Retail Markets between 2015 and 2017

Underlying the risk management of pesticides to protect human health and to facilitate trade among nations are sound scientific data on the levels of compliance with standards set by governments and internationally from monitoring of the levels of pesticides in foods. Although glyphosate is among the universally used pesticides in the world, monitoring has been hampered by the analytical difficulties in dealing with this highly polar compound. Starting in 2015, using liquid chromatography/tandem mass spectrometry (LC-MS/MS) that permits accurate and reproducible determination of glyphosate, the prevalence, concentrations, and compliance rates were determined. In this work, the glyphosate residues contents of 7955 samples of fresh fruits and vegetables, milled grain products, pulse products, and finished foods collected from April 2015 to March 2017 in the Canadian retail market are reported. A total of 3366 samples (42.3%) contained detectable glyphosate residues. The compliance rate with Canadian regulations was 99.4%. There were 46 noncompliant samples. Health Canada determined that there was no long-term health risk to Canadian consumers from exposure to the levels of glyphosate found in the samples of a variety of foods surveyed. The high level of compliance (99.4% of samples with the Canadian regulatory limits) and the lack of a health risk for noncompliant samples indicate that, with respect to glyphosates, the food available for sale in Canada is safe.

Glyphosate Determination by Coupling an Immuno-Magnetic Assay with Electrochemical Sensors

Glyphosate (N-(phosphonomethyl)glycine) is the most frequently used broad-spectrum herbicide worldwide. Its mechanism of action is based on the inhibition of an enzyme that is essential to plant growth. Its intensive use has caused global contamination to occur, which has not only affected the ecosystems, but even food and other objects of common use. Thus, there is a pronounced need for developing analytical methods for glyphosate determination in different matrices. Here, an electrochemical competitive immunoassay, based on the use of antibody-modified magnetic particles, has been developed. Tetramethylbenzidine (TMB) has been used as an enzymatic substrate. The extent of the affinity reaction has been achieved by monitoring the current value, due to the reduction of the enzymatic product. A disposable screen-printed electrochemical cell has been used. The calibration curve has been recorded in the 0⁻10,000 ng/L concentration range, with a detection limit of 5 ng/L and quantification limit of 30 ng/L. The electrochemical immunoassay has also been applied to the analysis of spiked beer samples.