The analysis of pesticide residues in food is nowadays an increasingly important task. Quality control has to be very strict in order to safeguard the consumers’ health. One of the most important goals of food quality assurance is testing food for residues and contaminants. Among chemical hazards, the contamination of food with pesticides has been characterized as a significant source of many serious diseases. Consumption of food containing pesticide residues may cause cancer, malformations, and damage to the endocrine, nervous, and immune system. In order to assure human food safety, The European Community has established maximum residue limits (MRL) of pesticides permitted in products of animal or vegetable origin that are intended for human consumption. In the EU, Regulation (EC) No. 396/2005 of the European Parliament and Council on pesticide residues established the levels of pesticide residues allowed in food and feed. To ensure the compliance of marketed food commodities with the law on food safety, sensitive and reliable analytical methods for the determination of pesticide residues are required. Multiresidue liquid chromatography-mass spectrometry methods (LC-MS) are widely recognized as an ideal, highly specific, and extremely sensitive technique for testing food products. This review discusses LC-MS approaches applied most widely to pesticide residue analysis over the last few years. The main ionization methods and MS detectors used as analytical tools in quantification and/or identification/confirmation of pesticide residues in food are presented.

This review presents applications of spectroscopic methods, infrared and Raman spectroscopies in the studies of the structure of gluten network and gluten proteins (gliadins and glutenins). Both methods provide complimentary information on the secondary and tertiary structure of the proteins including analysis of amide I and III bands, conformation of disulphide bridges, behaviour of tyrosine and tryptophan residues, and water populations. Changes in the gluten structure can be studied as an effect of dough mixing in different conditions (e.g., hydration level, temperature), dough freezing and frozen storage as well as addition of different compounds to the dough (e.g., dough improvers, dietary fibre preparations, polysaccharides and polyphenols). Additionally, effect of above mentioned factors can be determined in a common wheat dough, model dough (prepared from reconstituted flour containing only wheat starch and wheat gluten), gluten dough (lack of starch), and in gliadins and glutenins. The samples were studied in the hydrated state, in the form of powder, film or in solution. Analysis of the studies presented in this review indicates that an adequate amount of water is a critical factor affecting gluten structure.

The aim of the research is to evaluate pesticide residue contamination of fresh and frozen fruits and vegetables, agricultural raw material, purchased from Polish farmers for production of frozen fruits and vegetables, and the estimation of the multiresidue method effectiveness expressed as the proportion of pesticides detected in food samples to the total number of pesticides analyzed by multiresidue methods. A total of 144 samples (of black currants, red currants, raspberries, cherries, strawberries, blackberries, cauliflowers and broccoli) were analyzed using LC-MS/MS method for the determination of 60 pesticides. QuEChERS extraction, matrix-matched calibration and dynamic multiple reaction monitoring method were used. Residues of 15 compounds, mainly fungicides and insecticides, were detected in 46 samples. The percentage of samples with residues above the maximum residue levels (MRL) was 15%, whereas samples with residues below MRL were 17%. A total of 13 samples contained more than one pesticide residue. Pesticide residues were detected most often in samples of black currants (50%), broccoli (36.4%), raspberries (29%) and red currants (21.8%). The most frequently detected pesticides were carbendazim and acetamiprid. The proportion of pesticides detected during our study to the total number of analyzed pesticides amounted to 25%. It was compared to literature findings. For three fourth of multiresidue methods, the proportion was below 50% for methods developed for the analysis of less than 100 pesticides, and below 30% for methods developed for the analysis of more than 100 pesticides. It appears that a lot of efforts and means is lost on pesticides never or rarely detected in examined samples. The workload and cost effectiveness of the development and application of multiresidue methods along with the range of pesticides covered by the method should be carefully and thoroughly considered anytime when a new method or workflow is developed. Including non-targeted screenings in pesticide residue control seems to be an alternative worth considering.