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Simple Summary: Food waste is increasing globally as living standards rise and the population grows. Effective management approaches are required to reduce environmental contamination. One growing alternative option is the bioconversion process, which treats organic waste using living organisms such as insects. Black soldier fly larvae (BSFL) can rapidly and effectively convert huge amounts of food waste into useful biomass, high in proteins and lipids, which can be utilized as animal feed or an alternative food source. Because microbiological safety and larval nutritional value are crucial, this study focused on how waste storage conditions affect these characteristics. The results showed that the waste handling method and its resulting quality significantly affect the microbial composition (load and diversity) and nutritional profile (protein, fat, and dry matter content) of BSFL. Waste storage in closed containers at refrigerator temperatures proved to be more suitable than open storage at room temperature, not only because of the improved microbial safety of the larvae but also because of a higher increase in the weight of the final larval biomass and accumulated protein content. This study suggests that proper waste handling methods can optimize the biodegradation process and improve BSFL quality and safety. This study assessed the bioconversion efficiency of Hermetia illucens larvae (BSFL) fed on food waste stored under different conditions, focusing on the nutritional and microbial quality of the resulting larval biomass. Food waste was prepared as a fresh diet (FD) or naturally contaminated and stored at 20–22 °C (OS-T, opened storage-tempered) or under refrigeration, at 5–8 °C (CS-C, closed storage-cooled). Refrigerated, closed storage (CS-C) led to the highest rates of waste reduction (91.0%) and bioconversion efficiency (30.2%), with larvae exhibiting the highest protein content (36.83%) compared to the FD (35.5%) and OS-T (34.71%) groups. Microbiome analysis revealed that the CS-C condition promoted beneficial yeasts like Pichia and Diutia, which correlated positively with improved protein content and microbial safety. In contrast, OS-T storage supported spoilage fungi (Mucor, Rhizopus) and elevated total aerobic counts (7.28 log CFU/g), indicating higher microbial risks. The observed trends in waste reduction and protein content most probably relate to differences in microbial profiles, as controlled cooling affected microbial dynamics, preserving substrate quality and supporting larval growth. These findings emphasize the importance of refrigerated, closed storage to optimize bioconversion, improve larval nutritional value, and minimize microbiological hazards. [ABSTRACT FROM AUTHOR]

The objective of this research was to analyse soil and garden compost as a remediation medium at the foothill´s locality of the Tribeč Mountains, Southwestern Slovakia, to determine the pH/KCl, Pb, NO3−-N, NH4+-N contents in soil and soil affected by compost (the ratio 1 : 1), to evaluate the statistical significance of pH/KCl in relation to Pb and inorganic forms of nitrogen, and to find whether garden compost affects the monitored parameters. The analyses were carried out using Atomic Absorption Spectrometry, and Colorimetric and Potentiometric methods. Ascertained values of exchange reactions in soil ranged from 5.74 to 6.83 and exchange reactions in soil affected by garden compost ranged from 6.78 to 7.98. According to the calculated indices of dependencies, the development of pH/KCl values can be evaluated as moderately dynamic. The obtained results were evaluated statistically using the SAS 9.4 software method by the Spearman's correlation coefficient. The results in the observed three-year period showed that NO3−-N contents in soil had reached 14.73 mg.kg−1, NH4+-N 9.50 mg.kg−1, Nin 23.05 mg.kg−1, Pb 67.38 mg.kg−1, soil affecting by remediation medium – garden compost (the ratio 1 : 1) showed that NO3−-N contents had reached 23.93 mg.kg−1, NH4+-N 26.42 mg.kg−1, Nin 42.63 mg.kg−1, Pb 64.71 mg.kg−1 dry matter. Statistical dependence was high (P <0.01), which was demonstrated for soil pH : soil + compost Pb, soil + compost pH : soil + compost Pb. The garden compost influenced pH/KCl, reduced Pb levels, and increased the proportion of inorganic forms of nitrogen in soil. [ABSTRACT FROM AUTHOR]

Recent reports of P. olsonii causing postharvest rot of cherry tomatoes emphasize the need for effective strategies to prolong fruit shelf life. This study is the first to explore the use of essential oils (EOs), recognized for their antimicrobial properties, as a potential method to prevent postharvest losses from P. olsonii. Antifungal activity was tested for ten EOs at a concentration of 625 μL/L using the vapor diffusion method. Thyme, wild thyme, savory, oregano, and marjoram completely inhibited fungal growth over 14 days. Thyme EO, at a minimum inhibitory concentration (MIC) of 250 μL/L, fully inhibited all strains, while oregano, wild thyme, and savory were effective at 500 μL/L. Marjoram EO showed weaker activity. The lowest IC90 values, ranging from 35.72 to 162.72 μL/L, were estimated for thyme and oregano. In cherry tomatoes, oregano EO completely halted P. olsonii growth at 250 μL/L; thyme was effective for seven days; wild thyme and savory for two days. Thyme EO prevented P. olsonii spore germination at 500 μL/L for seven days, though germination occurred at half that concentration. The IC90 values varied between 256.2 and 138.7 μL/L depending on the strain. The vapor phase of EOs at 125 μL/L influenced the sensory characteristics of cherry tomatoes; however, for thyme and oregano, this effect was not negative due to their culinary association with tomato flavor. The selected EOs could be used to control and prevent postharvest fruit losses, but further research is needed to optimize their application. [ABSTRACT FROM AUTHOR]

The questionable safety of food spoiled by microorganisms is and should be the subject of attention and investigation. Pathogens such as Penicillium expansum are more difficult to control due to their resistance and ubiquity. Awareness of plant essential oils (EOs) as alternative natural preservatives is increasing because of their significant antimicrobial activity. The aim of this research work was therefore to contribute to this topic with new results. The antifungal activity of twelve EOs was tested in vitro against five strains of Penicillium expansum, using the vapour-phase diffusion method. Three EOs, from bergamot, star anise and rosaline, inhibited colony growth during two-week cultivation with a partial efficacy, all other EOs showed complete (100%) inhibitory activity at a concentration of 625 μL.L-1. These (EOs from clove, cinnamon, cinnamon bark, laurel, lemongrass, peppermint, Mitcham mint, spearmint, and lavender) were included in the second part of the trial, the aim of which was to determine their minimum inhibitory doses (MIDs). In the case of peppermint, Mitcham mint, spearmint and lavender EOs, some strains of P. expansum grew already at a concentration of 500 μL.L-1. Clove EO stopped the fungal growth of two strains at 250 μL.L-1. Laurel EO was 100% effective at MID 250 μL.L-1 throughout the cultivation period. EOs from lemongrass and cinnamon bark had similar efficacy on the strains. Both EOs were able to inhibit one strain at a MID of 125 μL.L-1, cinnamon bark EO inhibited the remaining strains at 250 μL.L-1, lemongrass EO inhibited three strains at 250 μL.L-1 and one at 500 μL.L-1. The lowest MID was recorded for cinnamon EO, which effectively inhibited two strains at 125 μL.L-1, two strains at 62.5 μL.L-1 and one strain even at 31.25 μL.L-1. The sensitivity of the strains used in this study varied according to the EOs used. [ABSTRACT FROM AUTHOR]

Essential oils (EOs) are a suitable alternative for extending the shelf life of foods. The aim of this research was to test the effect of fifteen EOs extracted from plants of the Lamiaceae family on five strains of Cladosporium cladosporioides. Cladosporium cladosporioides is frequently found on fruit and may be involved in fruit spoilage. The strains used in the study were isolated directly from lesions on berries. The growth of the fungi on the fruit was the reason for its rejection from sale. The antifungal activity of EOs against Cladosporium cladosporioides strains was determined by the microatmospheric method (625 μl EO/L air) during 14 days of cultivation. Thirteen EOs: thyme and red thyme (from Thymus vulgaris L.), mitcham mint (Mentha x piperita L. var. Mitcham), peppermint (Mentha x piperita L.), savory (Satureja hortensis L.), sage (Salvia officinalis L.), spearmint (Mentha spicata L. var. crispa), lavender (Lavandula angustifolia Mill.), marjoram (Origanum majorana L.), bergamot-mint (Mentha citrata Erh.), wild thyme (Thymus serpyllum L.), hyssop (Hyssopus officinalis L.), and oregano (Origanum vulgare L.) were shown to inhibit growth of all strains to 100%. Basil (Ocinum basilicum L.) and rosemary (Rosmarinus officinalis L.) EOs did not have a 100% inhibitory effect on all strains throughout the cultivation period. Subsequently, minimum inhibitory concentrations (MIDs) were determined using the microatmospheric method. LD90 and LD50 values were estimated by probit analysis. Based on the MID, LD90, and LD50 results, the essential oils can be divided into three groups. The first group (most effective): thyme, red thyme, spearmint, wild thyme, and oregano EO; the second group: peppermint, lavender, mitcham mint and savory EO; the third group: sage, marjoram, bergamot-mint and hyssop EO. The most effective EOs can be used to suppress the growth of Cladosporium cladosporioides in the vapour phase. [ABSTRACT FROM AUTHOR]

In this study, contamination by microscopic fungi (focused on Penicillium and Aspergillus species) of 75 fruit samples (strawberries, blackberries, blueberries, raspberries, grapes) and 29 tomato samples, which were obtained from Slovak stores was investigated. Totally 93.3% of fruit samples were contaminated with micromycetes (70.6% Botrytis spp., 52.0% Cladosporium spp., 42.7% Penicillium spp., 13.3% Rhizopus spp., 8.0% Alternaria spp., 6.7% Mucor spp., 5.3% Aspergillus spp., 4.0% Fusarium spp., and 1.3% Epicoccum spp.) and 6.7% of samples were contaminated with yeasts. The presence of 15 species of the genus Penicillium in fruits, namely P. atramentosum, P. aurantiogriseum, P. brevicompactum, P. bialowiezense, P. citrinum, P. crustosum, P. digitatum, P. expansum, P. fellutanum, P. glabrum, P. hordei, P. italicum, P. kiamense, P. olsonii, and P. purpurescens was found. With the highest frequency, P. brevicompactum (12.0%) and P. expansum (10.7%) were isolated from fruits. Four isolates of the genus Aspergillus were isolated from fruit samples (A. section Clavati, A. section Flavi, and two isolates of A. section Nigri). Thin layer chromatography (TLC) was used for testing of mycotoxin production by selected fungal isolates. Overall, 93.3% of tested Penicillium isolates and one tested Aspergillus of section Clavati proved the ability to produce at least one of the tested mycotoxins. As for tomato samples, 93.1% were contaminated with microscopic filamentous fungi (79.3% Penicillium spp., 24.1% Botrytis spp. and Alternaria spp., 10.3% Cladosporium spp., Mucor spp. and Rhizopus spp., 6.9% Aspergillus spp. and 3.4% Fusarium spp.) and 6.9% samples were contaminated with yeasts. In 65.5% of tomato samples, the occurrence of 8 species of the genus Penicillium (P. brevicompactum, P. crustosum, P. expansum, P. griseofulvum, P. italicum, P. olsonii, P. sublectaticum, P. thomii), and two species of the genus Aspergillus (from section Circumdati and Flavi) was recorded. P. olsonii (58.6%) and P. griseofulvum (10.3%) were isolated with the highest frequency. All 7 tested Penicillium isolates (100.0%) and 1 isolate of the genus Aspergillus (section Flavi), which were obtained from tomatoes, had the ability to produce at least one of the tested mycotoxins. Aspergillus section Flavi isolate (from tomatoes of Slovak origin) produced 5.5 μg.mL-1 of aflatoxin B1, 4.2 μg.mL-1 of aflatoxin B2, 154.4 μg.mL-1 of aflatoxin G1, and 5.6 μg.mL-1 of aflatoxin G2 on 14th day of cultivation on liquid YES medium at 25±1 °C in darkness, and detected by high pressure liquid chromatography (HPLC). [ABSTRACT FROM AUTHOR]

Species of the Rhizopus genus are often involved in the moulding of bread and bakery products. Essential oils (EOs) are a suitable alternative to extend the shelf life of food. This research was focused on testing the effect of selected EOs on the growth of Rhizopus species. Tested strains were isolated from mouldy breads. The antifungal activity of EOs against R. stolonifer and R. oryzae strains was determined by micro-atmospheric method (625 μL EO/L air) during 7 days of cultivation. Eight EOs, thyme, red thyme, savory, caraway, marjoram, wild thyme, and oregano 100% inhibited the growth of all strains. Basil, sage, and anise EOs only partially inhibited the growth of strains. Subsequently, the minimum inhibitory doses were determined using micro-atmospheric method. Minimal inhibition doses were 250 μL/L for thyme and red thyme EO, 250 and 500 μL/L for savory EO, 250 and 500 μL/L for oregano EO, 500 and ˃500 μL/L for wild thyme EO, ˃500 μL/L for caraway and marjoram EOs. Strains of the genus Rhizopus reacted differently to the presence of EOs. Thyme and red thyme were evaluated as the most effective EOs in this study. [ABSTRACT FROM AUTHOR]

A high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) was evaluated for the monitoring of aflatoxin B1 (AFB1) production by Aspergillus section Flavi isolates, which were found in the commodities of Slovak origin (barley and tomatoes). Rapid validation of the method was performed and the method was applied for the determination of the mycotoxin. Based on the calculated validation characteristics, the method showed high sensitivity and reproducibility. The LOD and LOQ determined were 0.03 and 0.10 μg.mL-1 which is fully acceptable for the determination of the AFB1 in isolates from plant commodities. The calibration graph was linear in the concentration range of 0.01-10.0 μg.mL-1. The optimized method was used for the analysis of the mycotoxin in three Aspergillus section Flavi isolates. The submerse cultivation was performed at 25±1°C in yeast extract sucrose liquid medium and material was collected on the 7th, 14th and 21st day of cultivation. Simple sample extraction was carried out with use of ethyl acetate, and measurement was done with use of the mobile phase consisting of water and methanol by HPLC-FLD. Production of the AFB1 by isolates was ranging from -1) to 49.38 μg.mL-1 with the highest concentration on the 14th day of cultivation. The maximum level of AFB1 was achieved by the Isolate 1 (isolated from barley, Kolíňany, 2018). [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the fungicidal effect of eight essential oils against five strains of the genus Rhizopus. Strains were obtained from various moldy foods, namely Rhizopus stolonifer KMi 383 from chestnut, R. stolonifer KMi 510 from strawberry, R. stolonifer KMi 511 from nectarine, R. stolonifer KMi 524 from cherry tomatoes, and R. lyococcus KMi 512 from blackberry. The essential oils (EO) used in this study were jasmine EO (extract from Jasminum officinale L.), bergamot EO (Mentha aquatica L. var. citrata (Her.) Fresen), bitter orange EO (from Citrus aurantium L.), grapefruit EO (Citrus paradisi Macfady), sweet flag EO (East Asian Calamus, from Acorus calamus L. var. angustatus Bes), star anise EO (from Illicium verum J.D.Hook), geranium EO (from Pelargonium graveolens), and lemongrass EO (from Cymbopogon citratus DC). The semi-quantitative composition of the essential oil samples was determined by gas chromatography coupled with mass spectrometry (GC-MS). The antifungal activity of essential oils against the strains of R. stolonifer and R. lyococcus was determined during 7 days, using the micro-atmosphere method (0.625 μL.mL-1 of air). Two essential oils, geranium and lemongrass, completely inhibited the growth of all isolates. Bitter orange essential oil inhibited the growth of all isolates of Rhizopus stolonifer, but isolate of Rhizopus lyococcus began to grow after four days of cultivation. In conclusion, certain essential oils are highly effective in the vapor phase. These could be used in further tests of their antifungal activity and could be used in the control of Rhizopus spp. or other fungal pathogens. [ABSTRACT FROM AUTHOR]

Honey is a remarkably complex food with a valued place in the human diet. An important indicator of its quality is the presence of microorganisms. This study aimed to monitor the mycological quality of 27 samples of Slovak kinds of honey and honey products with the addition of differently processed blueberries, cranberries, and red currants. Yeast and filamentous microscopic fungi were monitored using the plate dilution method. A total of 21 samples (78%) were positive for the presence of yeasts and 14 samples (52%) were positive for the filamentous microscopic fungi occurrence. In 6 samples (22%) no presence of microscopic fungi was found at all. The highest number of yeasts (3.07 log CFU.g-1 ) was recorded in one flower honey sample and in other samples, yeast counts did not exceed 3 log CFU.g-1 . The highest numbers of filamentous micromycetes (2.39 and 2.44 log CFU.g-1 ) were recorded in 2 honeydew honey samples. Overall, the following genera have been identified: Alternaria, Arthrinium, Aspergillus (including previously named as Eurotium), Aureobasidium, Cladosporium, Mucor, Penicillium, and Stemphilium. Penicillium spp. were recorded with the highest isolation frequency (41%). Aspergillus species were isolated from 19% of honey samples. In the honey with fruit addition, the yeasts in a range of 1.00 – 3.09 log CFU.g-1 and the filamentous microscopic fungi in a range of 1.00 – 1.39 log CFU.g-1 were found. The study showed that cranberries were the most appropriate addition from a mycological point of view. Dried and lyophilized forms of tested fruits were the most suitable. Except for honey with frozen currants and honey with fresh cranberries, all final products had a water activity below 0.610 and appeared to be stable. [ABSTRACT FROM AUTHOR]

The aim of this study was focused on the determination of the inhibitory effect of selected essential oils on the growth of five isolates of Geotrichum candidum. The isolates were obtained from the dairy products of domestic origin (sour cream, raw cow's milk, base for production of the brand, unsalted cheese, and cheese made from cows' milk). We studied the impact of five essential oils [pure essential oil EOs (100%)] - clove, basil, rosemary, fennel and thyme at concentration of 0.625 µL.cm-3 of air. Gas chromatography-mass spectrometry (GC-MS) analysis was used for the identification of the main components of EOs. We tested the effect of the essential oils by the gaseous diffusion method. The isolates were cultivated on PDA (Potato dextrose agar), in the dark, at 25 ±1 °C, 14 days. The diameter growing of colonies we continuously measured on the 3rd, 7th, 11th, and 14th day of cultivation. The results of the paper suggest that clove and thyme essential oil had 100% inhibitory effect on the growth of all tested isolates. Fennel, basil and rosemary essential oil had not significant inhibitory effects on tested isolates Geotrichum candidum. However, these oils affected the growth of colonies throughout the cultivation. Fennel EO had 100% inhibition only on the growth of one isolates of Geotrichum candidum to the 3rd day of cultivation. Basil EO had the stimultating effect on the growth of two isolates of G. candidum (KMi 322 and KMi 189). Our results showed that clove and thyme essential oil could be used as a natural preservative useful in the food industry. [ABSTRACT FROM AUTHOR]

The aim of this research was to determine the inhibitory effect of vapor phase of five essential oils (EOs) on the growth of seven strains of Penicillium commune isolated from moldy milk products. Another objective was to determine the minimum inhibitory doses (in vitro and probit analyses) of EOs, which at concentration 625 µL.L-1 of air completely inhibited the growth of all strains. The antifungal activity was evaluated by the micro-atmosphere method. The essential oils used in this study were extract of plants from family Myrtaceae. Only one essential oil - clove (from Syzygium aromaticum L.; leaves) completely inhibited the growth of all strains during cultivation at 25 °C and 5 °C. Eucalyptus essential oil (from Eucaliptus globulus; leaves), tea tree essential oil (from Melaleuca alternifolia Cheel; leaves), cajeput essential oil (from Melaleuca leucadendra L.; leaves and twigs), niaouli essential oil (from Melaleuca quinquenervia (Cav.) S. T. Blake; leaves) have different effects on the growth of P. commune strains. The order of tested essential oils according to the inhibition effect on the growth of the strains of P. commune (from the strongest to the weakest effect) was: clove > tea tree > cajeput > niaouli > eucalyptus. Clove EO that completely inhibited the growth of all strains was used to determine minimum inhibitory doses (MIDs). The MIDs were 125 µL.L-1 of air for two strains of P. commune and 250 µL.L-1 of air for five strains of P. commune on the 7th and 14th day of cultivation, also. Using probit analysis, predicted MIDs90 and MIDs50 were calculated. The MIDs90 were determined from 104.93 to 301.37 µL.L-1 of air. [ABSTRACT FROM AUTHOR]

Various food commodities of Slovak origin were analysed for the occurrence of Alternaria species-groups. Totally we analysed 14 samples of grapes, 3 samples of barley, 2 samples of wheat, 17 samples of fruit, vegetable and fruit-vegetable juices, 6 samples of red kuri squash with macroscopically visible infection. Mycological analyses were performed by using plate dilution method, method of direct placing of berries or grains on the plates with dichloran, rose bengal and chloramphenicol agar or by direct inoculation by mycological needle to the identification medium (potato-carrot agar). In all grape, barley, wheat and squash samples the presence of representatives of this genus was detected (100% isolation frequency). In juices, 41% of the samples were positive for their occurrence. The highest relative density of Alternaria isolates was found in grape samples (87%). All detected strains were segregated into four morphological species-groups: A. alternata, A. arborescens, A. infectoria and A. tenuissima. The most dominant species-group in grapes was A. arborescens, in barley and wheat A. tenuissima, followed by A. alternata, in juices only A. alternata and A. arborescens species-groups were detected and isolates of squashes were not classified to the species-groups. Randomly selected 67 isolates were analysed for the ability to produce mycotoxins alternariol (AOH), alternariol monomethylether (AME) and altenuene (ALT) by means of thin-layer chromatography. Of all tested isolates, AOH production was most frequently reported (70% of tested isolates). AME was produced by 60% and ALT by 49% of tested isolates. The largest share of the productive strains originated from the squashes, where all tested isolates produced ALT and AOH, followed by isolates of juices. From the viewpoint of individual species-groups, A. arborescens isolates and Alternaria spp. appeared to be the most productive in all mycotoxins tested. [ABSTRACT FROM AUTHOR]