Lemon postharvest losses are mainly due to the presence of fungal diseases. Current postharvest decay strategies rely on synthetic chemical fungicides; however, consumers are demanding that fruit is free of any chemical residue. The use of new natural alternatives, including essential oils, is emerging due to their potential antimicrobial activity. Therefore, the aim of this work is the elucidation of the effect of carvacrol, eugenol, and thymol, individually and in combination, applied in preharvest. Three different concentrations (100, 500, and 1000 µL/mL) of carvacrol, eugenol, and thymol were individually applied and in combination in ‘Fino’ and ‘Verna’ lemon cultivars. The fungal incidence (mainly Penicillium digitatum and P. italicum) was evaluated weekly for 35 days. Moreover, the main different quality parameters (weight loss, firmness, colour, total soluble solids, titratable acidity, and total phenolic content) of lemons were evaluated at harvest and after 35 days of cold storage. The results showed that carvacrol at the lowest concentration (100 µL/L) provided the lowest fungal incidence with a non-negative effect on the lemon quality parameters during storage, while the highest concentrations and the combination of essential oils resulted in the opposite effect. Therefore, carvacrol applied at 100 µL/L in preharvest could be an eco-friendly alternative to the current fungicides to control lemon decay, while maintaining their optimal quality.

Oats are highly susceptible to infection by Fusarium species, especially F. langsethiae, F. poae and F. sporotrichioides which contaminate the grain with mycotoxins. Climate change is expected to affect fungal colonisation and associated mycotoxin production. The objective of this study was to examine the effect of acclimatisation to elevated CO₂ on the growth and mycotoxin production capacity of these fungal species. Strains of F. langsethiae (FL; seven strains), F. poae (FP; two strains) and F. sporotrichioides (FS; one strain) were acclimatised by sub-culturing for 10 generations at either 400 or 1000 ppm CO₂ under diurnal temperature conditions. At each sub-culturing, the effect of acclimatisation to elevated CO₂ on (a) lag phase prior to growth, (b) growth rate on oat-based media was assessed. Additionally, the production of type A trichothecenes and related toxic secondary metabolites of sub-cultures after 1, 7 and 10 generations were assessed using LC-MS/MS qTRAP. The results showed that Fusarium strains had an increased lag time and growth rate in response to the combined effect of sub-culturing and elevated CO₂ levels. T-2 + HT-2 production was affected by elevated CO₂ in strain FL4 (7.1-fold increase) and a decrease in strain FL1 (2.0-fold decrease) at the first sub-culturing and FS (1.3-fold decrease) after 7 sub-cultures compared to ambient conditions. The effect of sub-culturing on T-2 + HT-2 production varied depending on the fungal strain. For strain FL4, significantly less T-2 + HT-2 toxins were produced after 10 generations (4.4-fold decrease) as compared to that under elevated CO₂ conditions after one sub-culture, and no change was observed under ambient conditions. The FS strain showed significant stimulation of T-2 + HT-2 toxin production after 10 sub-cultured generations (1.1-fold increase) compared to the initial sub-culture of this strain under elevated CO₂ conditions. The production of other toxic secondary metabolites was generally not impacted by elevated CO₂ conditions or by sub-culture for 10 generations, with the exceptions of FL1 and FP1. FL1 produced significantly more neosolaniol after 10 generations, when compared to those after 1 and 7, regardless of the CO₂ conditions. For FP1, elevated CO₂ significantly triggered beauvericin production after an initial sub-culture when compared to ambient conditions at the same sub-culture stage (29-fold). FP1 acclimatisation to elevated CO₂ led to a decrease of beauvericin production after 10 generations when compared to 1 (6-fold). In contrast, sub-culturing for 10 generations compared to 1 under ambient CO₂ conditions resulted in an increase in this toxin (12-fold).

Potato is the fourth most consumed crop in the world. More than half of the crop is stored for three to nine months at cold temperatures (3–10 °C) for the fresh and seed market. One of the main causes of fresh potato waste in the retail supply chain is the processing of fungal and bacterial rots during storage. Dry rot is a fungal disease that mainly affects the potato crop during storage and is responsible for 1% of tuber losses in the UK. It is produced by Fusarium spp., such as Fusarium sambucinum and F. oxysporum, which can lead to the accumulation of mycotoxins in the potato tuber. Little is known about the impact of environmental factors on the accumulation of mycotoxins in potato tubers. Understanding the ecophysiology of these fungi is key to mitigating their occurrence under commercial storage conditions. Therefore, this work aimed to elucidate the effect of three different temperatures (5, 10, and 15 °C) and two different water activities (a_w; 0.97, 0.99) on the ecophysiology and mycotoxin accumulation of F. sambucinum and F. oxysporum in a potato-based semi-synthetic medium. The mycotoxin accumulation was then studied in vivo, in potato tubers cultivated under organic farming conditions, stored for 40 days at 8.5 °C. Results showed that higher temperatures and a_w enhanced fungal growth, lag time, and mycotoxin accumulation in vitro. Growth rate was 2 and 3.6 times higher when the temperature increased from 5 to 10 and 15 °C, respectively. Six different mycotoxins (T-2, HT-2, diacetoxyscirpenol, 15-acetoxyscirpenol, neosolaniol, and beauvericin) were detected in vitro and in vivo. T-2 was the most abundant mycotoxin detected in vitro, observing 10⁶ ng of T-2/g media after 21 days of incubation at 10 °C and 0.99 a_w. Due to the long period of time that potato tubers spend in storage, the fluctuations of environmental factors, such as temperature and relative humidity, could promote the development of fungal rot, as well as mycotoxin accumulation. This could result in important food and economic losses for the potato market and a threat to food safety.

The quality of sweet orange (Citrus sinensis L.) is determined by the presence of decay caused by phytopathogenic fungi. This can develop in the field and rapidly spread among oranges during postharvest storage. Currently, the conventional treatments applied to control this problem are chemical fungicides. However, consumers demand eco-friendly and non-polluting alternatives with low chemical residues. Therefore, the aim of this work is the preharvest application of sodium bicarbonate (SB) and potassium silicate (PS) solutions at 0.1 and 1% to Navel and Valencia oranges to elucidate the effect on fruit quality and fungal decay at harvest and after 42 days of storage at 8 °C. Results showed that oranges treated with SB 0.1%, PS 0.1, and PS 1% maintained quality traits at similar levels to the control ones. However, SB 1% reduced firmness and increased weight loss, respiration rate, maturity index, and citrus color index. The total carotenoid content significantly increased in oranges treated with SB 1%, and no differences were observed in the other treatments compared to the control. Total antioxidant activity and total phenolic content decreased in oranges treated with SB at 0.1 and 1%, contrary to the results observed in oranges treated with PS, where both parameters increased. Regarding fungal decay, the best results were obtained in oranges treated with the highest doses of SB and PS. Therefore, the use of SB and PS in preharvest sprays could be an alternative to control fungal decay without affecting orange quality.

The commercialisation of fresh-cut artichokes with optimal quality and appearance and a maximum shelf-life is a great challenge for the artichoke market. The use of different anti-browning agents has been previously studied; however, their effect is still limited. Therefore, the objective of this study is the evaluation of the effect of L-cysteine and, in combination with a mixture of essential oils components (eugenol, thymol and carvacrol) on browning, quality and bioactive compounds of fresh-cut artichokes stored for 9 days at 2 °C. Four different treatments were applied to ‘Blanca de Tudela’ fresh-cut artichokes: cysteine and cysteine with 75, 150 and 300 µL of the essential oils components (EOs) mixture. After 2, 4 and 9 days of storage, physicochemical parameters (weight loss, colour, respiration rate) and functional (total phenolic content, antioxidant activity) were studied. A descriptive sensorial analysis was also carried out to evaluate sensory attributes. Results showed that the application of cysteine and 150 µL of EOs displayed the lowest browning and highest antioxidant properties, as well as the best quality and sensory parameters. The use of this post-harvest treatment on fresh-cut artichokes would result in a natural and eco-friendly solution to improve artichoke quality and shelf-life.