Humic substances are organic ubiquitous components arising in the process of chemical and microbiological oxidation, generally called humification, the second largest process of the carbon cycle. The beneficial properties of these various substances can be observed in many fields of life and health, whether it is the impact on the human organism, as prophylactic as well as the therapeutic effects; animal physiology and welfare, which is widely used in livestock farming; or the impact of humic substances on the environment and ecosystem in the context of renewal, fertilization and detoxification. Since animal health, human health and environmental health are interconnected and mutually influencing, this work brings insight into the excellence of the use of humic substances as a versatile mediator contributing to the promotion of One Health.

Foods of animal origin are controlled for antibiotic and coccidiostat residues. The rapid residue detection is possible using reliable broad-spectrum screening tests. This study’s objective using four microbial inhibition tests for the detection and identification of antibiotic and coccidiostat residues in different foods of animal origin: Premi^®Test, EXP Ampulle test, Milchtest and Screening Test for Antibiotic Residues (STAR). Four hundred and thirty (430) food samples (165 animal tissues, 152 raw cow’s milk and 113 eggs) were randomly collected and screened. Using the Premi^®Test, 18 samples were positive and 6 samples dubious. Using the EXP Ampulle test, 31 samples were positive and 2 samples dubious. Using the Milchtest, 15 samples were positive and 12 samples dubious. Using the STAR, 65 samples were positive with 62 samples positive on plates specific for beta-lactams and sulphonamides, 4 samples on plates specific for aminoglycosides, 8 samples on plates specific for macrolides and beta-lactams; and 7 samples on the plates specific for tetracyclines. Retesting using penicillinase and para-aminobenzoic acid (PABA) to confirm the presence of beta-lactams or sulphonamides all potentially positive tube test samples revealed 21 samples positive for beta-lactams and 27 samples positive for sulphonamides. Further testing of sulphonamide positive chicken samples revealed the positivity for coccidiostat salinomycin which was confirmed by testing with PABA, which counteracting salinomycin inhibition. Three hundred and sixty six (366) animal food samples were negative for antibiotic and coccidiostat residues. Microbial inhibition tests are preferred for initial antibiotic screening and have also proven useful for coccidiostat screening and post-screening.

Comparison of four microbiological inhibition tests for the screening of antimicrobial residues in the tissues of food-producing animals

The work deals with the issue of standardization and more accurate methodology for the isolation of gluten DNA in gluten-free products of plant origin, which is more demanding due to the more complex structure of plant cells. Three isolation methods were compared, of which the combination of glass and zirconium beads, Proteinase K and a commercially produced isolation kit was confirmed to be the most effective procedure. The given isolation procedure was more effective in one-component gluten-free foods, where the concentration of the obtained DNA ranged from 80.4 ± 0.7 to 99.0 ± 0.0 ng/µL. The subsequent PCR reaction revealed the presence of gluten not only in guaranteed gluten-free products (40%), but also in naturally gluten-free foods (50%). These were mainly gluten-free sponge cakes, gluten-free biscuits “Cranberries”, cocoa powder, coffee “3in1”, and instant coffee.

Salinomycin is a coccidiostat approved as a feed additive for the prevention of coccidiosis in poultry. Official control of its residues is set by the Commission Delegated Regulation (EU) 2022/1644. The aim of our study was to assess the suitability of three microbial inhibition tests (MITs), Premi^®Test, Explorer 2.0, and the Screening Test for Antibiotic Residues (STAR) linked to the enzyme-linked immunosorbent assay (ELISA), for the screening of salinomycin residues in the tissues of broiler chickens (breast and thigh muscle, heart, liver, gizzard, kidneys, lungs, spleen, skin, and fat) fed commercially produced feed containing 70 mg.kg⁻¹ of salinomycin in the complete feed. The first residue screening (Sampling A) was performed on the last day of administration of the salinomycin-medicated feed (day 30), and the second screening (Sampling B) was performed on the day of slaughter (day 37) after the expiry of the withdrawal period with the feeding of non-medicated feed. Based on the quantitative confirmation of salinomycin residues in the examined chicken tissues by the ELISA method (Sampling A from 0.025 to 0.241 mg.kg⁻¹; Sampling B from 0.003 to 0.076 mg.kg⁻¹), all the MITs with the preference of the bacterial strain Bacillus stearothermophilus var. calidolactis ATCC 10149 demonstrated the ability to detect the residues of salinomycin in the examined tissues of broiler chickens at the level of the maximum residue limits set from 0.015 to 0.150 mg.kg⁻¹ by Commission Implementing Regulation (EU) 2017/1914 and confirmed the relevance of their sensitivity to the coccidiostat salinomycin.

The eggshells of 120 experimental one-day-old table eggs were contaminated with the spore suspension of Cladosporium cladosporioides, divided into three groups (A–C) and stored at three different temperatures (3 °C, 11 °C and 20 °C) for 28 days. Visible growth of molds on/in experimental eggs was not observed within the entire storage period. No significant differences in the numbers of molds were found between particular groups of eggs. However, the composition of egg mycoflora was greatly influenced by storage conditions. Three mold genera were identified using the PCR method. The highest mold numbers were determined on Day 14 (Groups A and C) and Day 21 (Group B) when the maximum relative humidity and dew point temperature were recorded. On the same days, the dominance of Penicillium spp. and the minimum eggshell firmness were observed. Noticeable changes in egg quality were observed in eggs stored at 20 °C, and most of these eggs were downgraded at the end of storage period. The growth ability differed significantly among three mold genera. Penicillium spp. and Fusarium spp. showed better growth intensity at increased values (0.91–0.94) of water activity (a_w) indicating a possible risk associated with the occurrence of mycotoxins in the egg contents.