Preharvest Conditions Research Articles

Light emitting diodes for the improvement of postharvest quality of wild rocket in soilless and soil-bound cultivation systems

Wild rocket (Diplotaxis tenuifolia (L.) DC cv. Dallas) is a leafy green vegetable appreciated for its pungent taste and healthy properties, often consumed as a ready-to-eat product. The cultivation system is crucial in determining the overall quality, while postharvest storage is fundamental for preserving nutritional quality, phytochemicals, and vitamins. This study aimed to investigate the phytochemical content and microbiological quality of soilless (SS) and soil-bound (SB) wild rocket during cold postharvest storage under blue, red, and green Light Emitting Diode (LED). Blue LED increased chlorophylls and carotenoids in SB after two days of storage, and chlorophyll a in SS after seven days. Furthermore, it reduced H2O2 levels after two days (SS and SB) and lipid peroxidation in SB. Red LED increased phenols in both SS and SB but was detrimental to chlorophyll, carotenoids, and oxidative markers. Green LED had less significant effects. Microbiological growth varied with LED treatment: green light increased mesophilic bacteria in SB, and red light did so in SS by day four, while blue light reduced bacterial growth at the end of storage. Overall, Blue LED was the most effective LED in preserving postharvest quality. Soilless cultivation was particularly beneficial in reducing lipid peroxidation and maintaining cell membrane integrity during long-term storage, and it might also be more effective in preserving ascorbic acid. Conversely, soil-bound cultivation methods could enhance initial polyphenol content or better preserve it during early storage. This study highlights the complex interplay of pre-harvest conditions, postharvest quality, and shelf-life performance.

Factors influencing fumonisin B1 contamination in maize: insights from two production regions in Costa Rica.

Maize (Zea mays L.) is an important cereal crop worldwide. Contaminated maize kernels pose a significant mycotoxin exposure risk for humans in Latin America. Fumonisins, the most prevalent mycotoxin in maize, typically occur during pre-harvest conditions leading to significant economic losses. Various factors, including weather conditions, may influence this contamination. This study aimed to determine the association between fumonisin B1 (FB1) contamination, prevalence of Fusarium verticillioides, weather conditions and kernel quality in the two primary maize production areas in Costa Rica (Brunca and Chorotega). All maize samples (100%) showed FB1 contamination, with higher concentrations in samples from Brunca region, consistent with the presence of F. verticilliodes. Weather conditions appeared to play an important role in this contamination, since Brunca region had the highest mean temperature and relative humidity after maize silking (R1) and the total monthly rainfall in this region was significantly higher during the last two months of maize cultivation (grain-filling and physiological maturity stages R3 to R6). Interestingly, this study found a negative correlation between grain damage and kernel contamination with FB1 and F. verticillioides. The concentration of mineral nutrients in kernels from both regions was largely similar. Most nutrients in kernels exhibited a negative correlation with FB1, particularly nitrogen. Zinc and phosphorus were the only nutrients in kernels showing a positive correlation with FB1 in samples from the Brunca region. The results highlight elevated levels of FB1 contamination in maize and contribute to a better understanding of pre-harvest factors influencing FB1 contamination in tropical conditions.

Postharvest Cold-Storage Behaviour of ‘Nadorcott’ Mandarin Fruit Remains Unaffected by Preharvest Shade Netting

During postharvest cold storage, fruit sustains physical and biochemical changes, which may result in physiological rind disorders that consequently affect the fruit’s marketability. Preharvest conditions are known to affect postharvest fruit quality, with the effect of preharvest shade netting being currently unknown. To this end, ‘Nadorcott’ mandarin (Citrus reticulata Blanco) fruit, grown under shade netting and without it, was harvested during two consecutive seasons from an orchard in Citrusdal, Western Cape, South Africa. The fruit was evaluated prior to, as well as after a 7-day shelf-life period following cold storage at either −0.6 or 4 °C for 14, 27 and 34 days, respectively, for changes in rind and pulp colour, rind carotenoids, soluble solid content (SSC), citric acid content and SSC/citric acid ratio. Weight loss and the incidence of rind physiological disorders (staining) were also recorded. The results showed that shade net did not affect the storage behaviour of the fruit, as no treatment differences were seen. However, a storage duration effect for both treatments was evident in some internal and external quality parameters, viz., weight loss percentage and carotenoid content increased over the storage duration. Inconsistency regarding the storage duration effect on the rind colour, SSC and acid content were evident between seasons, at both temperatures. Staining only occurred in the first season after 34 days at both temperatures. The results indicated that shade netting had no negative effect on the cold-storage behaviour of ‘Nadorcott’ fruit. However, contrasting findings from this study emphasized that the condition of the fruit at harvest plays a significant role in the postharvest behaviour of the fruit during cold storage, and different growing conditions may also be a contributable factor.

Characterization and pathogenicity of Aspergillus carbonarius on Coffea excelsa causing berry rot and premature fall in Southern Philippines

Mycotoxigenic fungi in the family Aspergillaceae are among the most popular pathogens associated with post-harvest conditions. However, a recent discovery of a disease in 30–year–old trees of Excelsa coffee that caused black rot and resulted in the premature falling of the coffee berries in the Philippines. This study aims to characterize the pathogen of Coffea excelsa berries under pre-harvest conditions. Aspergillus carbonarius was ascertained through the combined results of cultural, morphological, molecular, and phylogenetic analyses of the rDNA ITS region of the isolate obtained from thirty diseased berries of twenty coffee trees examined. The results of the pathogenicity test also verified the virulence of the fungus. Hence, this study confirms that the disease infection of A. carbonarius is not only limited to post-production but also initiates pre– harvest disease infection by causing black rot and premature fall of coffee berries in the Philippines.

Effect of preharvest conditions on cut-flower quality.

The cut flower industry has a global reach as flowers are often produced in countries around the equator and transported by plane or ship (reefer) mostly to the global north. Vase-life issues are often regarded as linked to only postharvest conditions while cultivation factors are just as important. Here, we review the main causes for quality reduction in cut flowers with the emphasis on the importance of preharvest conditions. Cut flower quality is characterised by a wide range of features, such as flower number, size, shape, colour (patterns), fragrance, uniformity of blooming, leaf and stem colour, plant shape and developmental stage, and absence of pests and diseases. Postharvest performance involves improving and preserving most of these characteristics for as long as possible. The main causes for cut flower quality loss are reduced water balance or carbohydrate availability, senescence and pest and diseases. Although there is a clear role for genotype, cultivation conditions are just as important to improve vase life. The role of growth conditions has been shown to be essential; irrigation, air humidity, and light quantity and quality can be used to increase quality. For example, xylem architecture is affected by the irrigation scheme, and the relative humidity in the greenhouse affects stomatal function. Both features determine the water balance of the flowering stem. Light quality and period drives photosynthesis, which is directly responsible for accumulation of carbohydrates. The carbohydrate status is important for respiration, and many senescence related processes. High carbohydrates can lead to sugar loss into the vase water, leading to bacterial growth and potential xylem blockage. Finally, inferior hygiene during cultivation and temperature and humidity control during postharvest can lead to pathogen contamination. At the end of the review, we will discuss the future outlook focussing on new phenotyping tools necessary to quantify the complex interactions between cultivation factors and postharvest performance of cut flowers.

Enzymatic Degradation of Aflatoxin Accumulation in Dry Maize Kernels as A Promising Post-Harvest Mitigation Strategy

Background: Aflatoxin is one of the most problematic fungal-produced toxins as it is responsible for massive global agricultural losses and is deleterious to both human and animal health. Contamination of crops by certain strains of Aspergillus fungi accumulate aflatoxin in both post- and pre-harvest conditions. Methods: In this report, we tested the aflatoxin-degradation efficiency of an endogenously expressed enzyme in harvested maize kernels. In post-harvest conditions, equivalent loads of A. flavus were used to infect harvested maize kernels previously engineered to express an aflatoxin-degrading enzyme from the Honey mushroom fungus. Results: No measurable, or significantly reduced, levels of aflatoxin were detected in all the enzyme-expressing harvested kernels initially and then 3 days post –harvest the transgenic kernels amassed aflatoxin. Conclusions: This is the first report of an enzyme degradation of aflatoxin in a crop in harvested kernels. This demonstrates the potential of this strategy to aid in the mitigation of aflatoxin in post-harvest conditions.

Desirability Assessment with the Aid of Satellite Imagery and Chorographic Data in the Areas with Agricultural Land use in Esfahan; Geo-Spatial Analysis and Fuzzy Approach Nexus

Background: Aflatoxin is one of the most problematic fungal-produced toxins as it is responsible for massive global agricultural losses and is deleterious to both human and animal health. Contamination of crops by certain strains of Aspergillus fungi accumulate aflatoxin in both post- and pre-harvest conditions. Methods: In this report, we tested the aflatoxin-degradation efficiency of an endogenously expressed enzyme in harvested maize kernels. In post-harvest conditions, equivalent loads of A. flavus were used to infect harvested maize kernels previously engineered to express an aflatoxin-degrading enzyme from the Honey mushroom fungus. Results: No measurable, or significantly reduced, levels of aflatoxin were detected in all the enzyme-expressing harvested kernels initially and then 3 days post –harvest the transgenic kernels amassed aflatoxin. Conclusions: This is the first report of an enzyme degradation of aflatoxin in a crop in harvested kernels. This demonstrates the potential of this strategy to aid in the mitigation of aflatoxin in post-harvest conditions.

Investigation of the Factors That Contribute to Fresh Fruit and Vegetable Losses in the Australian Fresh Food Supply Chain

Fruit and vegetables (FV) are the major source of bioactive compounds for human beings. FV supply chains are complex and sensitive due to various features, including the seasonality of products, variations in demand, and short shelf-lives. The amount of waste in FV supply chains is significant compared with other supply chains as 44% of fresh FV produced globally are wasted in the food chain. This large amount of waste has a significant impact on the economy, food security, available natural resources, and the environment. To reduce food losses in the fresh food supply chain (FFSC), the root causes of waste must be first identified. While a number of researchers have investigated food losses in Australia, most only consider a specific stage in the supply chain and multiple stages in the FFSC are often overlooked. Additionally, the impact of advanced storage technologies, packing, handling, and transport on food losses should be investigated. Furthermore, supply chain practices are changing in response to uncertainties, such as the pandemic and climate changes, which also need to be captured. This research aims to identify the key factors contributing to fresh fruit and vegetable losses through a comprehensive empirical study. Primary data were collected through a well-designed questionnaire-based survey targeting major stakeholders in the FFSC, including farmers, distributors, and retailers in Australia. The survey investigates current postharvest practices and the effects of these practices on food losses. The main factors influencing food losses were identified and the options to reduce these losses were outlined. The results showed that losses mostly occurred at the farm level, and picking practices and preharvest conditions largely contributed to FV losses. The results highlight the need for proper training and education for workers involved in harvesting and handling fresh produce.

Internal Flesh Browning in Apple and Its Predisposing Factors—A Review

This review article is focused on internal flesh browning (IFB)-related physiological disorders affecting apple (Malus domestica Borkh.) fruit. The expression of different physiological and metabolic IFB-related disorders during post-harvest storage are investigated along with the pre-harvest factors contributing to development. The effectiveness of commercially available pre-harvest technologies for preventing IFB-related disorders are also examined. Internal flesh browning-related disorders are erratic and devastating disorders that result in post-harvest deterioration of fruit quality in apples. Internal flesh browning-related disorders can result in severe economic losses to the apple industry through reduced consumer trust and market acceptability of susceptible cultivars. There are several IFB-related disorders and incidence can range from 0 to 100% of a crop, with severity ranging from no brown flesh to browning of the entire fruit flesh. While IFB-related disorders are found in several apple cultivars, some cultivars are more prone than others. The development of IFB-related disorders involve complex mechanisms depending upon the different types and causes, or factors involved in loss of structural integrity and functional stability of the cell membranes and cell components. Membrane disruption followed by enzymatic oxidation of fruit phenolic compounds by polyphenol oxidases and the production of brown polymers is considered to be the general underlying mechanism causing the browning of flesh tissue. It can be observed in different patterns based on the injured portion of the fruit flesh and the cause of membrane disruption. Three broad categories of IFB-related disorders, including chilling injury, internal CO2 injury, and senescent-related browning disorders, are discussed along with their sub-types. The development of IFB-related disorders can be influenced by both pre-harvest factors and post-harvest conditions and their interactions. Although commonly associated with storage, IFB can also be found immediately after harvest and sometimes in unharvested fruit prior to full maturity. As pre-harvest conditions are a strong contributor to IFB-related disorders, the influence of several pre-harvest orchard conditions, including fruit size, crop load, maturity at harvest, cultivar, climatic conditions, seasonal temperatures, growing degree days, and major mineral nutrients, such as nitrogen (N), phosphorus (P), potassium (K), and calcium (Ca) are reported. Although there are contradictory findings in the studies reported, in general, factors such as larger fruit size, light crop load and delayed harvesting, along with cool temperatures after bloom and warmer temperatures before harvest, increase the risk of IFB-related disorders. In relation to fruit mineral concentrations, high N and low Ca have been associated with increasing IFB, while there is conflicting evidence in relation to the impact of both P and K. This review also examines the effectiveness of commercial pre-harvest technologies such as 1-methylcyclopropene, aminoethoxyvinylglycine and diphenylamine in the prevention of IFB-related disorders, but none of these technologies were found promising due to varied and contradictory results.

Effect of Pre-harvest Periods by Replacing Nutrient Solution with Tap Water on Nitrate and Quality in Hydroponic Lettuce

Lettuce (Lactuca sativa L.) is a high-value nutritional food for human consumption, rich in minerals and vitamins. However, people are still concerned about the residues of nitrate content in hydroponic lettuce. Pre-harvesting by replacing nutrient solution with tap water is one of several factors that can help to reduce nitrate content and improve the quality of hydroponic lettuce. Therefore, this study focused on the effect of pre-harvest periods by replacing nutrient solution with tap water on nitrate and quality in hydroponic lettuce. This experiment was performed by replacing nutrient solution with tap water in a hydroponic system for 0 h, 24 h, 48 h, and 72 h before harvesting the lettuce product. Nitrate, vitamin C, phenolic, and soluble sugar contents were determined. The results showed that nitrate content was lowest under pre-harvest conditions for 72 h (19 mg/g dry weight, 63% reduction), but it was not significantly different for 48 h (20 mg/g dry weight, 61% reduction). The vitamin C content was significantly decreased after pre-harvesting for 72 h (5.3 µg/100 g, 30% reduction). The soluble sugar content was significantly increased and reached its highest content after pre-harvest for 48 h (3.3 mg/100 g, 105% increase), but there was no significant difference at 72 h (3.2 mg/100 g, 98% increase). Although the phenolic content decreased slightly, there was no significant difference among the treatments. In conclusion, nitrate contents were reduced the lowest, and soluble sugar contents were increased the highest after pre-harvest for 48 h. Vitamin C and phenolic contents were slightly decreased after pre-harvest periods by replacing the nutrient solution with tap water.

Complex regeneration responses of eight tree species to partial harvest in mixedwood forests of northeastern North America

Ecosystem-based forest management associated with partial harvesting (PH) is intended to balance ecological and economic values of sustainable forest management. The potential for delayed growth response and elevated mortality of advance regeneration following PH remains a critical concern, and may present a barrier to more widespread implementation of this approach. We used 835 permanent continuous forest inventory plots to examine the rate and time course of species-specific regeneration growth and mortality of eight tree species in the first fifteen years following operational partial harvests in the mixed-species forests of Maine, United States. We aimed to provide a quantitative understanding on how regeneration of different species responded to PH in terms of growth and mortality. In addition, we evaluated how the patterns and magnitudes of growth and mortality responses developed over time, if these responses occur gradually or suddenly, and if the patterns of the responses were persistent. We found that the response magnitude, temporal trajectories of responses, and the length of initial lag-period largely varied across species, PH treatments, and the variables examined. For sapling diameter growth, paper birch (Betula papyrifera Marshall) and red maple (Acer rubrum L.) showed immediate responses to high-intensity PH, while a five-year lag-period was observed in balsam fir (Abies balsamea (L.) Mill.), American beech (Fagus grandifolia Ehrh.), red spruce (Picea rubens Sarg.) and eastern hemlock (Tsuga canadensis (L.) Carrière) and a 10-year lag period in northern white-cedar (Thuja occidentalis L.). The initial increase in sapling mortality was observed in balsam fir, American beech, red maple and northern white-cedar, but not in other species. Sapling survival reached a stable state irrespective of species after the initial five-years following harvests. In partially harvested stands, identifying preharvest conditions related to postharvest density, growth, and mortality was complex and interacted with time since harvest. Our results suggest that broad application of PH only results in species-specific gains, losses, and delays in regeneration responses within mixed-species stands. Future research should consider PH in combination with other treatments to initiate immediate responses to a wider range of species.

Harvest Anticipation, Yield and Economic Feasibility of Wheat by Application of Non-Selective Herbicides

The present work aims to evaluate the possibility of anticipating the wheat harvest by the application of non-selective herbicides in the pre-harvest conditions, thereby providing productive and economic viability. In total, 13 treatments were executed, which includes the spraying of different herbicide combinations (glufosinate-ammonium, glyphosate, and paraquat) in the phenological stages (Z-83, Z-85, Z-87, Z-92), and treatments without application of herbicides. Further, the treatment step was followed by providing different harvest conditions such as (i) glufosinate-ammonium: 9.5 and 8.8 days, (ii) glyphosate: 11.2 and 10.9 days, and (iii) paraquat: 7.9 and 8.5, where the first numerical value corresponds to number of days for the year 2016 followed by 2017. A mean reduction in seed yield of 4.6 % (BRS Parrudo) and 25.4 % (TBIO Sinuelo) was observed upon application of herbicides in the first two phenological stages. Additionally, an economic loss reaching up to R$ 2512 ha-1, was demonstrated. Therefore, the application of the non-selective herbicides glufosinate-ammonium and paraquat in the pre-harvest results in wheat phytointoxication, however, promoting harvest anticipation in 4.8 and 5.3 days, respectively.

Практика защиты клубней картофеля от болезней и прорастания при хранении

All over the planet, potatoes are an important staple food crop. However, to maintain the quality of the tubers and increase their availability, it is necessary to store the tubers for a long time, often using industrial scale equipment. In this context, maintaining potato quality is critical for the seed, fresh and processing sectors. The industry has always innovated and invested in improved post-harvest storage. However, the rate of technological change is accelerating and will continue to accelerate. Stricter legislation and changing consumer attitudes are driving increased interest in creating alternative or complementary post-harvest treatments to traditional growth suppression and disease control chemicals. We are considering modern knowledge about the biochemical factors that determine the state of dormancy, as well as the influence of factors before and after harvest on ensuring the quality of potato tubers. In addition, the role of genomics as a future approach to improving potato quality is discussed. It is critical, thanks to more focused industry research, to understand how pre-harvest conditions affect tuber quality and the factors that determine the transition to dormancy, which should create the conditions for achieving sustainable storage.

Enzymatic degradation is an effective means to reduce aflatoxin contamination in maize

BackgroundAflatoxins are carcinogenic compounds produced by certain species of Aspergillus fungi. The consumption of crops contaminated with this toxin cause serious detrimental health effects, including death, in both livestock and humans. As a consequence, both the detection and quantification of this toxin in food/feed items is tightly regulated with crops exceeding the allowed limits eliminated from food chains. Globally, this toxin causes massive agricultural and economic losses each year.ResultsIn this paper we investigate the feasibility of using an aflatoxin-degrading enzyme strategy to reduce/eliminate aflatoxin loads in developing maize kernels. We used an endoplasmic reticulum (ER) targeted sub-cellular compartmentalization stabilizing strategy to accumulate an aflatoxin-degrading enzyme isolated from the edible Honey mushroom Armillariella tabescens and expressed it in embryo tissue in developing maize kernels. Three transgenic maize lines that were determined to be expressing the aflatoxin-degrading enzyme both at the RNA and protein level, were challenged with the aflatoxin-producing strain Aspergillus flavus AF13 and shown to accumulate non-detectable levels of aflatoxin at 14-days post-infection and significantly reduced levels of aflatoxin at 30-days post-infection compared to nontransgenic control Aspergillus-challenged samples.ConclusionsThe expression of an aflatoxin-degrading enzyme in developing maize kernels was shown to be an effective means to control aflatoxin in maize in pre-harvest conditions. This aflatoxin-degradation strategy could play a significant role in the enhancement of both US and global food security and sustainability.

Light Intensity Alters the Behavior of Monilinia spp. in vitro and the Disease Development on Stone Fruit-Pathogen Interaction.

The development of brown rot caused by the necrotrophic fungi Monilinia spp. in stone fruit under field and postharvest conditions depends, among others, on environmental factors. The effect of temperature and humidity are well studied but there is little information on the role of light in disease development. Herein, we studied the effect of two lighting treatments and a control condition (darkness) on: (i) several growth parameters of two Monilinia spp. (M. laxa and M. fructicola) grown in vitro and (ii) the light effect in their capacity to rot the fruit (nectarines) when exposed to the different lighting treatments. We also assessed the effect of such abiotic factors in the development of the disease on inoculated nectarines during postharvest storage. Evaluations also included testing the effect of fruit bagging on disease development as well as on ethylene production. Under in vitro conditions, lighting treatments altered colony morphology and conidiation of M. laxa but this effect was less acute in M. fructicola. Such light-induced changes under in vitro development also altered the capacity of M. laxa and M. fructicola to infect nectarines, with M. laxa becoming less virulent. The performance of Monilinia spp. exposed to treatments was also determined in vivo by inoculating four bagged or unbagged nectarine cultivars, indicating an impaired disease progression. Incidence and lesion diameter of fruit exposed to the different lighting treatments during postharvest showed that the effect of the light was intrinsic to the nectarine cultivar but also Monilinia spp. dependent. While lighting treatments reduced M. laxa incidence, they enhanced M. fructicola development. Preharvest conditions such as fruit bagging also impaired the ethylene production of inoculated fruit, which was mainly altered by M. laxa and M. fructicola, while the bag and light effects were meaningless. Thus, we provide several indications of how lighting treatments significantly alter Monilinia spp. behavior both in vitro and during the interaction with stone fruit. This study highlights the importance of modulating the lighting environment as a potential strategy to minimize brown rot development on stone fruit and to extent the shelf-life period of fruit in postharvest, market, and consumer’s house.

Petunia Performance Under Application of Animal-Based Protein Hydrolysates: Effects on Visual Quality, Biomass, Nutrient Content, Root Morphology, and Gas Exchange.

Sustainable plant production practices have been implemented to reduce the use of synthetic fertilizers and other agrochemicals. One way to reduce fertilizer use without negatively impacting plant nutrition is to enhance crop uptake of nutrients with biostimulants. As the effectiveness of a biostimulant can depend on the origin, species, dose, and application method, the aim of this research was to evaluate the effect of a commercial animal-based protein hydrolysate (PH) biostimulant on the visual quality, biomass, macronutrient content, root morphology, and leaf gas exchange of a petunia (Petunia × hybrida Hort. “red”) under preharvest conditions. Two treatments were compared: (a) three doses of an animal-based PH biostimulant: 0 (D0 = control), 0.1 (D0.1 = normal), and 0.2 g L–1 (D0.2 = high); (b) two biostimulant application methods: foliar spray and root drenching. The dose × method interaction effect of PH biostimulant on the plants was significant in terms of quality grade and fresh and dry biomass. The high dose applied as foliar spray produced petunias with extra-grade visual quality (number of flowers per plant 161, number of leaves per plant 450, and leaf area per plant 1,487 cm2) and a total aboveground dry weight of 35 g, shoots (+91%), flowers (+230%), and leaf fresh weight (+71%). P and K contents were higher than in untreated petunias, when plants were grown with D0.2 and foliar spray. With foliar spray at the two doses, SPAD showed a linear increase (+21.6 and +41.0%) with respect to untreated plants. The dose × method interaction effect of biostimulant application was significant for root length, projected and total root surface area, and number of root tips, forks, and crossings. Concerning leaf gas exchange parameters, applying the biostimulant at both doses as foliar spray resulted in a significant improvement in net photosynthesis (D0.1: 22.9 μmol CO2 m–2 s–1 and D0.2: 22.4 μmol CO2 m–2 s–1) and stomatal conductance (D0.1: 0.42 mmol H2O m–2 s–1 and D0.2: 0.39 mmol H2O m–2 s–1) compared to control. These results indicate that application of PH biostimulant at 0.2 g L–1 as foliar spray helped to achieve extra-grade plants and that this practice can be exploited in sustainable greenhouse conditions for commercial production of petunia.

Survival of Clostridioides difficile in finished dairy compost under controlled conditions.

The survival of Clostridioides difficile (previously Clostridium difficile) vegetative cells and endospores was compared at different levels of indigenous microflora using autoclaved and unautoclaved dairy composts with different moisture contents (MCs). Both types of composts adjusted to 20, 30 and 40% MCs were inoculated with a suspension of C. difficile that contained both vegetative cells (c.5-6 log CFU per gram) and endospores (c.5·0CFU per gram), and then stored aerobically inside a humidity-controlled chamber at room temperature 22·5±0·8°C for 1year. The level of indigenous microflora was very stable during the storage after day 7 in both types of compost. The greatest reductions of C. difficile vegetative cell counts occurred during the first 24h of storage in autoclaved and unautoclaved composts, which had 4·7 and 5·5 log CFU per gram with 20% MC, 1·8 and 2·1 log CFU per gram with 30% MC, and 2·3 and 1·3 log CFU per gram with 40% MC, respectively. Both MC and the duration of storage have significant (P<0·05) effects on the survival of vegetative cells for first 120days of storage. The slow inactivation of C. difficile vegetative cells at higher MCs during aerobic storage was confirmed by exponentially decaying modelling data during the early stage of aerobic exposure. The reduction of endospore counts (<1·0 log CFU per gram) during the storage for both types of compost at all MCs was not significant (P>0·05) except for the autoclaved compost with 30% MC. The highly resistant C. difficile endospores to the unfavourable environmental conditions survived for more than a year while vegetative cells died off exponentially upon the initial aerobic exposure. The long-term survival of C. difficile endospores in contaminated compost may transmit the pathogen to fresh produce, animals or water in pre-harvest conditions.

Phenolic and Carotenoid Profile of Lamb's Lettuce and Improvement of the Bioactive Content by Preharvest Conditions.

This study characterizes the phenolic, carotenoid and chlorophyll profile of lamb’s lettuce, a vegetable whose consumption in salads and ready-to-eat products is constantly growing. The MS/MS analysis allowed the identification of thirty-five phenolic compounds including hydroxybenzoic and hydroxycinnamic acids, flavanones, flavanols and flavanones, many of which are reported here in lamb’s lettuce for the first time. Chlorogenic acid was the principal phenolic compound found (57.1% of the total phenolic concentration) followed by its isomer cis-5-caffeoylquinic. Other major phenolic compounds were also hydroxycinnamic acids (coumaroylquinic, dicaffeoylquinic and feruloylquinic acids) as well as the flavones luteolin-7-rutinoside, diosmetin-apiosylglucoside and diosmin. Regarding carotenoids, seven xanthophyll and four carotenes, among which β-carotene and lutein were the major compounds, were detected from their UV-Vis absorption spectrum. In addition, chlorophylls a and b, their isomers and derivatives (pheophytin) were identified. Preharvest factors such as reduced fertilization levels or salinity increased some secondary metabolites, highlighting the importance of these factors on the final nutritional value of plant foods. Lamb’s lettuce was seen to be a good potential source of bioactive compounds, and fertilization management might be considered a useful tool for increasing its nutritional interest.

Climate Change Impact on Aflatoxin Contamination Risk in Malawi's Maize Crops

Malawi is one of the poorest countries in the world, with high levels of malnutrition and little domestic mycotoxin regulation. Domestically grown maize is the largest single source of calories in the country and a large contributor to the economy. This research uses Regional Climate Models (RCMs) to determine the climatic conditions in the three regions of Malawi (Northern, Central and Southern) in 2035 (2020–2049) and 2055 (2040–2069) as compared to the baseline climate of 1971–2000. This climatic data is then used as inputs to the Food and Agriculture Organization's (FAO) AquaCrop model to assess the impact on the growth cycle of two maize varieties grown in each region and sown at three different times during the planting season. Finally, AFLA-maize, a mechanistic model, is applied to determine the impact of these projected changes on the aflatoxin B1(AFB1) contamination risk. We find that Malawi's climate is projected to get warmer (by 1–2.5°C) and drier (reduction of 0–4% in annual rainfall levels) in all regions, although some uncertainty remains around the changes in precipitation levels. These climatic changes are expected to shorten the growing season for maize, bringing the harvest date forward by between 10 and 25 days for the short-development variety and between 25 and 65 days for the long-development variety. These changes are also projected to make the pre-harvest conditions for Malawian maize more favorable for AFB1contamination and risk maps for the studied conditions were drawn. Exceedances of EU safety thresholds are expected to be possible in all regions, with the risk of contamination moving northwards in a warming climate.

Pre-harvest conditions associated with Staccato sweet cherry fruit quality: mineral status in leaves and fruitlets and orchard growing factors

Data obtained over three growing years were examined with principal component analysis to study how cherry quality was affected by pre-harvest mineral status in leaves and fruitlets and by orchard growing factors. Higher foliar levels of calcium were correlated with lower levels of pitting and pebbling in stored cherries, however there was no relationship with these disorders and fruitlet calcium content. Temperature and leaf size were associated with pebbling and pitting levels in stored cherries. Leaf and fruitlet mineral content are not the only factors to be considered in understanding fruit quality; environmental effects and management techniques should also be considered.