The aim of the study was to compare the mineral content between the peel and the pulp of citrus fruits and to determine which citrus fruit, among orange (Citrus sinensis), pomelo (Citrus maxima), mandarin (Citrus reticulata Blanco), lemon (Citrus limon), key lime (Citrus aurantifolia), and red, yellow, or green grapefruit (Citrus paradisi), is the richest in minerals. The research material consisted of fresh citrus fruits belonging to the genus Citrus L in the family Rutaceae. The fruits were purchased at a supermarket at one time. To prepare laboratory samples, each fruit was cut in half, and one half was homogenized, treating the sample as a whole (peel + flesh), while the other half was peeled and the pulp (F) and peel (P) were homogenized separately. To determine the content of minerals (Na + , K + , Ca +2 , Mg +2 , Fe +2 , Zn +2 , Cu +2 , Mn +2 , and Se +2), the samples were mineralized and analyzed using an Analytik Jena PlasmaQuant PQ 9000 inductively coupled plasma optical emission spectrometer. The content of macro-and micronutrients in the peel of most of the fruits far exceeded their quantity in the pulp. Oranges and pomelos are the fruits richest in iron and copper, so they could be recommended in cases such as hemoglobin production disorders resulting from a deficiency of these elements. Oranges can additionally enrich the body with potassium, phosphorus, and manganese, while lime can be a source of calcium, zinc, sodium, and especially potassium. It should also be noted that all citrus fruits are a very valuable source of potassium, which is needed to ensure the water and electrolyte balance.

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This study aimed to compare the effect of Zn, Cu and Fe glycine chelates on the proximate composition, cholesterol levels, fatty-acid profile and dietary value of the thigh meat of broiler chickens. The experiment involved three hundred and fifty Ross 308 chickens divided into seven groups. The chickens were administered Zn, Cu and Fe glycine chelates in an amount corresponding to 50% of the requirement or 25% of the requirement for 42 days. It was found that the use of Zn, Cu and Fe glycine chelates did affect the fatty acid profile and dietary value of meat. A positive impact was most frequently (p < 0.05) noted in chickens receiving Zn chelate in an amount covering 50% of the requirement: the lowest levels of SFA and atherogenic and thrombogenic indices, the highest content of PUFA n−3 and PUFA/SFA ratios and hypocholesterolemic/hypercholesterolemic indices. Positive effects were more often recorded for chickens receiving Zn in an amount corresponding to 50% of the requirement. The results did not show that the use of Cu and Fe glycine chelates can reduce the dietary value of thigh meat in broiler chickens since, generally, the outcomes were not worse than those in the control group. It should be highlighted that due to ambiguous results, it is impossible to determine a dose of Cu and Fe glycine chelate which would be more efficient for broiler chickens. However, chickens receiving chelates in amounts corresponding to 25% of the requirement showed far better results.

The presence of heavy metals in food is a global problem. The paper aimed to examine the content of cadmium (Cd) and lead (Pb) in instant coffee and instant coffee substitutes. The safety of consumption of the beverages by adult Poles was estimated based on the following parameters: tolerable weekly intake (TWI) %, benchmark dose lower confidence limit (BMDL) %, chronic daily intake (CDI), target hazard quotient (THQ) and hazard index (HI), for three beverage consumption patterns—one, two or three servings a day. Forty-nine samples of coffee, instant coffee drinks and coffee substitutes were analysed. The content of cadmium and lead was determined by ICP (inductively coupled plasma) analysis. The maximum level of Cd in the analysed beverages was 3.2 µg, and that of Pb was 82.6 µg per 1 kg. The tolerable level of intake of Cd (TWI) and Pb (BMDL) with the analysed beverages did not exceed 2.5%. The value of CDI, THQ and HI was not higher than 1, which means that the risk of diseases related to chronic exposure to Cd and Pb consumed with coffee should be evaluated as very low. However, special note should be taken of Pb, as the level of this metal was higher than that of Cd, and for beverages with a higher weight per serving (e.g. Cappuccino), the intake of Pb can exceed consumer-safe levels if they are consumed on a regular basis. Therefore, it should be considered whether it is advisable for flavoured multi-ingredient instant coffee drinks to be consumed from time to time only, and natural coffee with optional milk and/or sugar be the choice of regular coffee drinkers.

This manuscript presents the results of development and adoption of the confirmatory UPLC- MS/MS method for determination of sulfonamides and trimethoprim residues in whole and powdered cow's milk samples. Sample preparation includes a recovery with water (in the case of milk powder), separation of milk fat by centrifugation at 4 °C, proteins precipitation with acetonitrile using ultrasonic intensification, extraction of analytes with a two-component mixture of organic solvents from weak acidic phosphate buffer solution, concentration of obtained extracts, degreasing and reconstitution with the mobile phase. The use of tandem-mass spectrometric detector in multiple reaction monitoring mode provides high specificity for all ten sulfonamides, which molecules contain the same structural elements, and trimethoprim, as three ion transitions were used for each of the target analytes. The approach of matrix matched calibration on the milk matrix was applied, and it allowed us to disregard taking into consideration the absolute extraction of analytes during sample preparation, as well as the influence of sample matrix components on analytes ionization. The main advantages of the developed technique are simplicity, rapidity and cost effective sample preparation, fast procedure of sample analysis (the time of chromatographic separation is 2.0 min), high selectivity, and sensitivity at the level of ≤ 0.5 μg/kg (as compared with the maximum residues level of sulfonamides in dairy products, viz. 100 μg/kg). According to the European Commission Decision 2002/657/EC, the values of CCα and CCβ for sulfonamides and trimethoprim in milk were calculated. The capability of the method was confirmed on the basis of the established validation parameters, using spiked milk samples and "added – found" approach. The method was tested during the analysis of spiked samples of whole and powdered cow's milk (CV ~ 20%). The developed technique was verified by interlaboratory comparative testing of milk powder samples for sulfonamides content. The UPLC-MS/MS method for the determination of sulfonamides and trimethoprim residues in whole and milk powder samples can be used both for routine laboratory analysis of dairy products and for the examination of suspicious or questionable samples.