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The aim of this study was to examine the microbiological quality of raw donkey milk of an indigenous Serbian breed as well as the changes in the microbial populations during storage at 4 °C. In addition, antibacterial activity of donkey milk against E. coli, L. monocytogenes and S. aureus at 15 °C as well as the content of the two main antibacterial proteins lysozyme and lactoferrin were investigated. Microbiological examination of 137 individual milk samples collected over a period of 21 months showed good microbiological quality since foodborne pathogens such as Salmonella spp. and L. monocytogenes were not detected in any of the analyzed samples, while the number of E. coli, Enterobacteriaceae, total coliform bacteria, sulfite-reducing Clostridia and aerobic sporogenic bacteria was below the limit of quantification (<1 cfu mL−1). During the six-days storage at 4 °C, total bacterial counts and the counts of lactic acid bacteria remained at the initial level while pathogenic bacteria were not detected. The strongest antibacterial activity of the tested milk was observed against E. coli, while S. aureus was the least sensitive to milk antibacterial compounds. Although further research is needed to fully elucidate the antibacterial mechanism and synergistic activity of different compounds in donkey milk, the high content lysozyme (2.63 ± 0.03 g L−1) and lactoferrin (15.48 mg L−1) observed in tested milk could contribute to its strong antibacterial activity and extension of the storage period during which it can be safely consumed.

This study aimed to test different chemical agents to obtain microbiologically safe industrial hemp seeds that could be used for further food processing (with the reduced total number of microorganisms, total number of moulds and yeasts, and total number of Enterobacteriaceae). In order to obtain seeds applicable for food consumption, optimal storage temperature conditions (room temperature, refrigerator, freezer), method of seed packaging (vacuum/without vacuum), and the application of various chemical treatments (ethanol, sodium hydrogen carbonate, sodium hypochlorite) were tested on the certified industrial hemp seeds, produced in two consecutive years. Optimal storage conditions differed for different microorganisms, and the most optimal storage was at room temperature, for seeds produced in 2018, in the treatment to reduce the total number of Enterobacteriaceae and the total number of microorganisms. When storing seeds from 2018 in order to reduce the number of yeasts and moulds, a slightly lower number was spotted when seeds were stored in a vacuum-sealed bag, at the refrigerator/freezer temperature. For hemp seeds produced in 2019, the most optimal storage conditions were at the refrigerator (for reduction of the total number of Enterobacteriaceae) and freezer temperature (for reduction of the total number of microorganisms). For the reduction of the total number of moulds and yeasts, optimal conditions were at room temperature. Ethanol (75%, v/v) was the most effective disinfectant among the tested chemicals regardless of the initial number of microorganisms, with log reduction of 3.2 (for the total number of Enterobacteriaceae), 2.9 log (for the total number of microorganisms), and total reduction of the total number of yeasts and moulds after 10 minutes, for the seeds harvested in 2019, which were far more contaminated than the seeds harvested in 2018. Considering the price of the disinfection method with ethanol, sodium hypochlorite may be a better soluti, Cilj ovog istraživanja bio je ispitivanje različitih hemijskih sredstava za dobijanje mikrobiološki bezbednog semena industrijske konoplje, koje bi se moglo koristiti za dalju preradu u hranu (sa smanjenim ukupnim brojem mikroorganizama, ukupnim brojem kvasaca i plesni, i ukupnim brojem enterobakterija). Da bi se dobilo seme primenljivo za ishranu, optimalni temperaturni uslovi skladištenja (sobna temperatura, frižider, zamrzivač), način pakovanja semena (vakuum/bez vakuuma) i primena različitih hemijskih tretmana (etanol, natrijum hidrogen karbonat, natrijum hipohlorit) su testirani na sertifikovanom semenu industrijske konoplje, proizvedenom u dve uzastopne godine. Optimalni uslovi skladištenja su se razlikovali za različite mikroorganizme, a najoptimalnije skladištenje je bilo na sobnoj temperaturi, za seme iz 2018. godine, a u cilju smanjenja broja enterobakterija i ukupnog broja mikroorganizama. Pri skladištenju semena iz 2018. godine u cilju smanjenja broja plesni i kvasaca primećen je nešto manji broj datih mikroorganizama kada je seme čuvano u vakuumski zatvorenoj vrećici, na temperaturi frižidera/zamrzivača. Za seme konoplje iz 2019. godine najoptimalniji uslovi skladištenja su bili na temperaturi frižidera (za redukciju broja enterobakterija) i u zamrzivaču (za redukciju ukupnog broja mikroorganizama). Za smanjenje ukupnog broja plesni i kvasaca, optimalni uslovi su bili na sobnoj temperaturi. Etanol (75%, v/v) je bio najefikasnije sredstvo za dezinfekciju među ispitivanim hemijskim sredstvima, bez obzira na početni broj mikroorganizama, sa log smanjenjem od 3,2 (za ukupan broj enterobakterija), 2,9 log (za ukupan broj mikroorganizama) i ukupnim smanjenjem broja kvasaca i plesni nakon 10 minuta delovanja, za seme proizvedeno 2019. godine, koje je bilo mnogo više kontaminirano u odnosu na seme iz 2018. godine. Uzimajući u obzir cenu metoda dezinfekcije etanolom, natrijum hipohlorit može biti bolje rešenje za smanjenje broja mikrobiota na semenu.