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The aim of the present study was to develop meat-based media with compositions similar to those of dry-fermented meat products and to evaluate their use in studying the growth of Aspergillus parasiticus and the kinetics of aflatoxin B1 (AFB1) production. In our previous experiments, we found that the strain A. parasiticus ŽMJ7 produced a high amount of AFB1. Cooked meat agar (CMA2) was used as a novel complex meat-based medium with four variations: CMA2G (CMA2 supplemented with 1% glucose), CMA2YE (CMA2 supplemented with 0.2% yeast extract), and CMA2GYE (CMA2 supplemented with 1% glucose and 0.2% yeast extract). Media were inoculated with an A. parasiticus spore suspension (105 spores/mL) and incubated at 25 °C for up to 15 days. The A. parasiticus lag phase lasted less than 1 day, irrespective of the growth medium, with the exception of control medium CMA1 (cooked meat agar) as an already known meat-based medium. The highest mean colony growth rate was observed on CMA2 and CMA2G. Reversed-phase UPLC–MS/MS analysis was performed to determine the AFB1 concentration in combination with solid phase extraction (SPE). The highest AFB1 concentration in meat-based media was detected in CMA2GYE after 15 days of incubation (13,502 ± 2367 ng/mL media). The results showed that for studying AFB1 production in dry-fermented meat products, novel suitable media such as CMA2-based media are required. This finding could represent a potential concern with regard to the production of dry-fermented meat products.

Uporaba fungicidov za zatiranje plesni, ki povzročajo kvar sadja in zelenjave, je vse bolj omejena. Vzroki so v dolgoletni preobsežni uporabi fitofarmacevtskih sredstev (FFS), razvoju novih sevov plesni, ki so prilagojeni ali celo odporni proti fungicidom ter v potencialno škodljivih vplivih ostankov pesticidov na zdravje ljudi. Zato so pomembne alternativne metode in ena od njih je uporaba modre LED-svetlobe, katere osnovni mehanizem temelji na fotodinamični inaktivaciji (PDI). Namen diplomskega dela je pojasniti fotodinamični vpliv modre LED-svetlobe in možnosti uporabe v praksi za zaviranje kvara sadja in zelenjave, ki ga povzročajo plesni. Pregled strokovne literature o uporabi modre LED-svetlobe na plodovih sadja in zelenjave med skladiščenjem je pokazal spodbudne rezultate. Pri obsevanju plesni na/v živilu z modro LED-svetlobo se tvorijo reaktivni kisikovi radikali (ROS), ki povzročijo poškodbe različnih celičnih sestavin kot so lipidi, proteini in nukleinske kisline, ki lahko vodijo do inhibicije rasti ali celo celične smrti in propada plesni. Modra LED-svetloba lahko vpliva tudi na samo kakovost živil, npr. sprememba barve plodov, povečanje vsebnosti nekaterih antioksidantov, kot so fenolne spojine, antocianini, upočasni se gnitje in staranje pridelkov ter poveča odpornost plodov proti boleznim, povzročenim s strani plesni. Uporaba modre LED-svetlobe predstavlja okolju prijaznejšo metodo v primerjavi z uporabo fungicidov in bi jo lahko komplementarno povezovali z drugimi metodami za zaščito in podaljšanje trajnosti sadja in zelenjave. Ker na učinkovitost modre LED- svetlobe vpliva veliko dejavnikov, bo za njeno uporabo v praksi potrebnih še veliko raziskav. The use of fungicides to control molds that cause spoilage of fruits and vegetables is increasingly limited. Mainly due to their excessive use in past, the development of new resistant mould strains and because of potentially harmful effects of pesticide residues to human health. Alternative methods are therefore increasingly important. One of them is irradiation of fruits and vegetables with blue LED light or photodynamic inactivation (PDI) with blue LED light. Researchers have demonstrated the antimicrobial effect of blue LED light mainly as antibacterial treatment and less frequently as antifungal treatment. The purpose of this work is to explain photodynamic effect of blue LED light irradiation and possibilities of its practical application as antifungal method used to prevent fruit and vegetable spoilage. The results have showed potential of blue LED light irradiation as it can inactivate mould by producing reactive oxygen species (ROS) that cause damage to different cellular components such as lipids, proteins and nucleic acids. These effects can lead to growth inhibition or even moulds destruction. Blue LED light might also affect quality of fruit and vegetables such as colour, increasing content of certain antioxidants, such as phenolic compounds, anthocyanins, slows rot and aging of fruits and vegetables and increase their resistance to mold-borne diseases. The use of blue LED light is a more environmentally friendly method compared to the use of fungicides and could be use as complementary strategies to protect fruit and vegetables from mould spoilage. As the efficiency of blue LED light is influenced by many factors, its application still requires many scientific research.

Jabolka zaradi svoje visoke vodne aktivnosti in vsebnosti sladkorjev omogočajo ugodne razmere za rast različnim plesnim. Najpogosteje se omenja plesni vrste Penicillium expansum, ki povzročajo modro plesen. Na jabolkih so te plesni sposobne sintetizirati sekundarne metabolite, med katerimi so tudi mikotoksini. V jabolkih in izdelkih iz jabolk je najbolj pogost patulin, ki je imunotoksičen in nevrotoksičen za ljudi, če se zaužije v visokih koncentracijah. Mejna vrednost za največjo dovoljeno vsebnost patulina v izdelkih iz jabolk je 50 µg/kg. Plesni najpogosteje vstopajo v notranjost sadja skozi poškodovano površino, kar se zgodi ob močnem dežju, napadu insektov ali neprevidnem rokovanju. Pogosto pride do okužb s plesnimi šele v skladiščnih prostorih. Najbolj priporočljivo je skladiščenje jabolk v hladilnicah in hladilnicah s kontrolirano atmosfero, kjer je nivo CO₂ in O₂ prilagojen tako, da je zorenje plodov čim bolj upočasnjeno. Kljub nizkim temperaturam in nizkim nivojem O₂ je rast plesni vrste P. expansum le upočasnjena in patulin še vedno lahko proizvajajo. Zato je patulin lahko prisoten v različnih izdelkih iz jabolk. Ker pa je patulin tudi termostabilen, je njegovo odstranjevanje zelo zahtevno. Učinkovito zniževanje vsebnosti patulina so pokazali nekateri procesi obdelave hrane, kot so čiščenje, pasterizacija in fermentacija. Poznamo pa tudi več fizikalnih, kemijskih in bioloških procesov odstranjevanja patulina iz izdelkov iz jabolk. Sem spadajo obdelava s toploto, svetloba UV, elektroporacija, uporaba visokih tlakov, ozona in mikroorganizmov. Nekateri postopki delujejo na principu adsorpcije patulina, drugi pa povzročajo njegovo degradacijo. Tudi s temi procesi obdelave odstranitev patulina iz končnih izdelkov ni možna v celoti, hkrati pa lahko pride tudi do nezaželenih sprememb v senzoričnih lastnostih in hranilni vrednosti živil. Apples provide favourable conditions for growth of various fungi, due to their high water activity and sugar content. Most commonly mentioned mould is Penicillium expansum, the cause of so called blue mould. On apples these fungi are able to synthesize secondary metabolites called mycotoxins. The most commonly present mycotoxin in apples and apple products is patulin, which is immunotoxic and neurotoxic to humans if ingested at high concentrations. The limit for maximum level of patulin in apple products is 50 µg/kg. Mould enters the fruit through the damaged surface, which occurs in case of heavy rain, insect attack or careless manipulation. However, mould infections often occur only in storage rooms. The most recommended way to storage apples is in refrigerated chambers and refrigerated chambers with controlled atmosphere, where the levels of CO₂ and O₂ are adjusted to slow down the ripening of the fruit. Despite low temperatures and low level of O₂ the growth of P. expansum is only slowed down and patulin can still be produced. Therefore, patulin can be present in various apple products. Since patulin is also thermostable, its removal is very difficult. Effective reduction of patulin has been demonstrated by certain food processing technologies, such as washing, pasteurization and fermentation. There are also several physical, chemical and biological processes of removing patulin from apple products. This includes heat treatment, light UV treatment, electroporation, use of high pressures, ozone and microorganisms. Some procedures function on patulin adsorption, while others provoke its degradation. Even with these processing technologies, the removal of patulin from apple products is not entirely possible, and there may also be negative changes in sensory quality and nutritional value of foods.

Plesni vrste Penicillium expansum povzročajo gnilobo številnih živil, med katerimi so te plesni najpogostejši kontaminanti jabolk. Ker plesni vrste P. expansum lahko tvorijo patulin, predstavljajo tudi tveganje za varnost živil. Glavni namen dela je bil določiti sposobnost njihove adhezije, saj večina strokovne literature opisuje bakterijsko adhezijo, medtem ko so raziskave adhezije plesni redke. V prvem delu smo metodo določanja adhezije z barvilom kristal vijolično (KV) optimizirali z izbiro gojišča (sladni agar in krompirjev agar) in starosti konidijev (7 in 10 dni) za pripravo inokuluma ter določitvijo valovne dolžine (570 nm in 584 nm) za kvantifikacijo adheriranih plesni. V drugem delu smo proučevali adhezijo plesni vrste P. expansum tako, da smo preverili vplive izbranih intrinzičnih in ekstrinzičnih dejavnikov. Rezultati so pokazali, da je za spremljanje adhezije boljše, ča uporabimo inokulum pripravljen iz 10 dni stare kulture, saj je bila adhezija tu veliko večja ter da gojišče, na katerem rastejo plesni za pripravo inokuluma, ne vpliva na adhezijo. Pri primerjavi rezultatov dobljenih z meritvami absorbanc sproščenega KV pri različnih valovnih dolžinah, razlik nismo zaznali. Med intrinzičnimi dejavniki smo ugotovili, da ima velik vpliv na adhezijo začetno število konidijev, saj je bila adhezija največja pri 108 K/ml (K: konidiji), ter čas adhezije plesni vrste P. expansum (adhezija po 20 urah je bila večja kot po 40 urah), medtem ko vrsta seva (tipski sev P. expansum ŽMJ 497, divji sev P. expansum ŽMJ 464) ni bistveno vplivala na adhezijo. Plesni vrste P. expansum dobro rastejo na številnih materialih, ki se uporabljajo tudi v živilski industriji, zato smo primerjali njihovo adhezijo na različnih površinah (polistiren, polipropilen, polietilen visoke gostote, polietilen tereftalat, steklo in nerjaveče jeklo). Največjo adhezijo smo določili na površini polistirena. Adhezijo plesni vrste P. expansum na vseh površinah smo opazovali tudi z vrstično elektronsko mikroskopijo in ugotovili, da so morfološke lastnosti povezane z vrsto površine. Zaključimo lahko, da je metoda barvanja s KV primerna kot preliminarna metoda določanja adhezije plesni in da se plesni vrste P. expansum dobro adherirajo na površino, vendar so potrebne nadaljnje raziskave. Strains of Penicillium expansum cause rotting of many foods, among which they are the most common contaminant of apples. As P. expansum can form patulin it is also a food safety risk. The main purpose was to determine P. expansum adhesion ability, since most scientific literature describes bacterial adhesion, while moulds adhesion is rare. In the first part, the method of determining adhesion with crystal violet dye (CV) was optimized by choosing medium (malt agar and potato agar) and age of conidia (7 and 10 days) for preparation of inoculum and determining the wavelength (570 nm and 584 nm) for adherence quantification. In the second part, we studied the adhesion of P. expansum by checking the influence of selected intrinsic and extrinsic factors. Results showed that for adhesion monitoring it is better to use an inoculum prepared from a 10-day-old culture, as the adhesion was much greater, and that the culture medium on which the moulds grow prior inoculum preparation, does not affect adhesion. When comparing the results obtained by measuring the absorbance of released CV at different wavelengths no differences were found. Among the intrinsic factors, we found out that initial number of conidia had a major influence since adhesion was highest at 108 K/ml (K: conidia), and adhesion time (adhesion after 20 h was greater than after 40 h), while strain (P. expansum ŽMJ 497 type strain, P. expansum ŽMJ 464 wild strain) did not affect adhesion. P. expansum strains grow well on many materials that are also used in food industry and we compared adhesion on different surfaces (polystyrene, polypropylene, high-density polyethylene, polyethylene terephthalate, glass and stainless steel). The maximum adhesion was determined on the polystyrene. Adhesion of P. expansum on surfaces was also observed by scanning electron microscopy and it was found that the morphological properties are related to the type of surface. We can conclude that the KV staining method is suitable as a preliminary method for determining mould adhesion and that P. expansum adhere well to the surface, but further research is needed.

V sklopu magistrskega dela smo želeli ugotoviti, kako praktičen pouk vpliva na spremembe v znanju in stališčih pri učencih sedmega razreda osnovne šole. Izvedli smo kvantitativno raziskavo, kjer smo uporabili kavzalno eksperimentalno metodo dela. Zasnovali smo vprašalnik s preizkusom znanja. Ta nam je služil kot orodje preverjanja znanja o plesnih in stališč učencev do njih. Učenci so anketni vprašalnik izpolnjevali dvakrat. Najprej pred začetkom eksperimentalnega dela in po eksperimentalnem delu (praktičen pouk). Z našo raziskavo smo ugotovili, da ni statistično pomembnih razlik v znanju med učenci pred poukom in po pouku, ravno tako se ne pojavljajo razlike glede na učno metodo. Učenci, ki so se učili na podlagi klasičnega pouka, ne kažejo sprememb v znanju v primerjavi z učenci, ki so se učili na podlagi praktičnega dela. Raziskava tudi ni pokazala razlik znanja glede na spol, deklice in dečki imajo primerljivo znanje o plesnih. Statistično pomembne razlike so se pojavile glede zanimanja (stališč) dečkov in deklic pri različnih učnih metodah. Dečki, s katerimi smo izvajali praktičen pouk, kažejo večje zanimanje za plesni. Zanima jih, kako plesni rastejo, radi bi proučevali plesni v naravi, zanima pa jih tudi, kaj bi zraslo na kruhu, zaprtem v kozarcu. In this thesis we wanted to find out how practical work affect the change in knowledge and attitudes towards molds in Seventh Grade students of Primary School. We have carried out a quantitative research in which we have used a cause/effect experimental method of work. We designed a questionnaire with a examination. With this questionnaire we have checked the knowledge and attitudes of the students towards molds. Students completed the survey questionnaire twice. First before the start of the experimental work and after the experimental work (practical work). With our research, we found that there are no statistically significant differences in knowledge between students before class and after class, and there are no differences according to the teaching method. Pupils who have learned through traditional lessons showed no changes in knowledge compared to pupils who have learned through practical work. The research also showed no differences in knowledge according to gender, girls and boys have comparable knowledge about molds. Statistically significant differences emerged regarding the interest (attitudes) of boys and girls in different teaching methods. The boys with whom we conducted practical classes show a greater interest in molds than girls. Boys are more interested in how molds grows, they would like to study molds in nature and they are also interested in what would grow on bread enclosed in a jar.