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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]

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]