Natural Occurrence Of Aflatoxins Research Articles

Mycobiota, Total Aflatoxins, And Ochratoxin A of Black And Green Cumin.

Because of the medical importance of cumin as well as it being one of the food additives to many Saudi dishes, there was a need to study the fungal load of this type of spice. This study aimed to determine the mycological profile of the retail black and green cumin distributed in different markets at western region, Saudi Arabia, using the dilution plat method on dichloran 18% glycerol (DG18) agar and incubation at 25°C. Using morphological criteria and molecular markers (internal transcribed spacer sequence), 39 species belonging to 18 genera were collected from different black cumin (33 species belonging to 17 genera) and green cumin (25 species belonging to 9 genera). Alternaria alternata, Aspergillus flavus, A. niger, A. ochraceus, Cladosporium cladosporioides, and Stemphylium botryosum were the most prevalent. Black cumin harbors fungal counts reaching 545 colony-forming units (CFU)/g, while green cumin included 500 CFU/g. Also, the natural occurrence of aflatoxins and ochratoxin A was also measured. Seventy-two cumin samples (90% of tested samples) showed toxin contamination. Aflatoxins and ochratoxin A ranged from 9.35 to 3.9 PPB in black cumin samples and from 4.08 to 5.75 PPB in green cumin samples.

Assessment of aflatoxin levels in whole and peeled ginger marketed in Dar-Es-Salaam, Tanzania

Aflatoxins are naturally occurring toxins, predominantly produced by the fungi Aspergillus flavusand Aspergillus parasiticus. These toxins are often found in numerous agricultural and food products worldwide. The current study investigated the natural occurrence of total aflatoxins in dried split ginger purchased from different local markets in the Dar-Es-Salaam region, the eastern zone of Tanzania. Using a cross-sectional sampling design, a total of 50 ginger samples were analyzed in two preparations as a whole and peeled ginger based on Q+ Aflatoxin single-step lateral flow immuno-chromatographic assay. The results revealed that all ginger samples analyzed were positive for aflatoxins with levels ranging from 5.7–28.0 mg/kg and 3.1–21.5 mg/kg for whole and peeled ginger respectively. Forty (80%) and fifteen (30%) of the samples for whole and peeled ginge respectively were above the Tanzanian legally permissible limit of 10 mg/kg. Interestingly, aflatoxins level of contamination in whole ginger were significantly higher than in peeled ginger (p<0.0001). This is the first report on the natural occurrence of aflatoxins in whole and peeled ginger samples from Tanzania. The findings of this study indicated that ginger peels are relatively prone to aflatoxin contamination.

Proximate composition and prevalence and exposure assessment of aflatoxins intake through consumption of fresh carrot and processed marketed carrot products in South Punjab, Pakistan

Carrot (Daucus carota L.) is a nutrient-rich vegetable that is widely cultivated and consumed in Pakistan in both raw and processed form. Data on the proximate composition and natural occurrence of aflatoxins (AFs) in carrots and marketed carrot products is lacking in Pakistan and the risk exposure of AF has not been characterised before. Thus, the current study was designed to know the frequently consumed carrot products with per capita consumption, and risk assessment of AF through these products in various regions of South Punjab Pakistan. A survey was conducted with 125 respondents and appeared that raw carrot, fresh carrot juice, gajrella and pickle are the most frequently consumed marketed carrot products with per capita consumption i.e. 62.5, 46.6, 16.2 and 14.5 gday-1, respectively. Proximate analysis revealed that carrot root and processed carrot products contained 9.65–98.2% moisture, 0.23–0.60% ash, 6.2–14.1% carbohydrates, 0.31–0.80% protein, 0.40–3.7% fat and 1.4–4.20% fibre. AF analysis revealed that 36.67% of samples were contaminated with TAF. Thirty-five (35%) percent of samples were tainted with aflatoxin B1, and 13.33% of samples were contaminated with aflatoxin B2. All the samples of carrot root, fresh carrot juice and gajrella contained TAF levels less than the maximum limit (ML) (2 ppb) assigned by the European Union (EU). However, the entire AFB1 positive samples of carrot pickle contained AFB1 levels of more than 2 ppb exceeding the ML. Furthermore, daily dietary exposure of TAFs ranged from 0.11 to 1.27 ng/kg of body weight per day which relatively exceeds the permissible limit of 1 ng/kg of body weight per day as defined by the Joint FAO/WHO Expert Committee on Food Additives. This is the first prevalence and risk assessment report of AF in marketed processed carrot products in Pakistan. These baseline data are an initial step in the effort to deal with this significant food safety issue and the establishment of legislation for AF in marketed products is needed in Pakistan.

Seasonal Variation in Aflatoxin Levels in Edible Seeds, Estimation of Its Dietary Intake and Vitamin E Levels in Southern Areas of Punjab, Pakistan.

A total of 779 samples of edible nuts (melon seeds, watermelon seeds, pumpkin seeds, and cantaloupe seeds) from Southern Punjab (Pakistan), were collected during the summer and the winter seasons. The natural occurrence of aflatoxins (AFs) and vitamin E (tocopherols) levels were investigated using HPLC. The results have shown that 180 (43.4%) of samples from the winter season and 122 (33.4%) samples from the summer season were found positive for AFs. Elevated average levels of total AFs (20.9 ± 3.10 μg/kg, dry weight) were observed in watermelon seeds without shell, and the lowest average amount (15.9 ± 3.60 μg/kg) were documented in melon seeds without shell samples from the winter season. An elevated average amount of total AFs 17.3 ± 1.50 μg/kg was found in pumpkin seeds available without a shell. The results have documented a significant difference in total AFs levels in edible seeds available with shells versus without shells (α = 0.05 & 0.01). The highest dietary intake of 6.30 μg/kg/day was found in female individuals from consuming pumpkin seeds (without shell) in the winter season. A value of 3.00 μg/kg/day was found in pumpkin seed without shell in the summer season in female individuals. The highest total tocopherol levels were 22.2 ± 7.70 ng/100 g in pumpkin seeds samples from the winter season and 14.5 ± 5.50 mg/100 g in melon seed samples from the summer season. The variation of total tocopherol levels in edible seeds among the winter and summer seasons showed a significant difference (p ≤ 0.0054), except watermelon seeds samples with non-significant differences (p ≥ 0.183).

Occurrence of aflatoxin- and ochratoxin A-producing Aspergillus species in Thai dried chilli

The present study aimed to examine the presence of aflatoxin- and ochratoxin A (OTA)-producing fungi in dried chilli ( Capsicum spp.). A total of 120 chilli samples, including 60 samples each of chilli powder and dried chilli pods, were examined for fungal contamination. Results showed that 86.7% and 96.7% of chilli powder and dried chilli pods, respectively, were contaminated by fungi at a concentration of <10 3 CFU/g. Overall, 500 fungal isolates were recovered and identified using a morphological method. The most frequent strain was Aspergillus section Flavi (46.6%), followed by Aspergillus section Nigri (34%), Penicillium (7.6%), Aspergillus section Aspergillus (7.6%), Aspergillus section Circumdati (2.2%) and Rhizopus (2%). In total, 37.5% and 43.8% of Aspergillus section Flavi isolates obtained from dried chilli powder and dried chilli pods, respectively, produced aflatoxin. Of the 96 aflatoxigenic isolates, 96.9% of the strains produced aflatoxin B and 3.1% produced both aflatoxin B and G. However, β-tubulin sequence analysis revealed that all aflatoxin-producing isolates were identical to A. flavus . Moreover, 170 isolates of Aspergillus section Nigri , 11 of Aspergillus section Circumdati , 2 of Aspergillus section Flavi producing yellow-to-cinnamon colonies and 38 of Penicillium spp. were examined for their ability to produce OTA. In total, 1 isolate of Aspergillus section Nigri and 2 isolates of Aspergillus section Flavi produced OTA. The first isolate was identified as A. carbonarius , whereas the latter two isolates were both A. alliaceus . The highest OTA production by A. carbonarius (622.4 ng/g) was observed following incubation on MEA at 25 °C for 21 days. Conversely, the two A. alliaceus isolates produced OTA at levels of 583.7 and 743.7 ng/g, respectively, after cultivation on YES at 25 °C for 21 days. To the best of our knowledge, this is the first report regarding the natural occurrence of aflatoxin- and OTA-producing fungi in dried chilli from Thailand. • More than 95% of dried chilli powder and dried chilli pods collected in Thailand was contaminated with fungi. • Aspergillus section Flavi is the most common species in dried chilli. • Aspergillus section Flavi in dried chili samples is frequently aflatoxigenic strain. • Ochratoxin A producing species, A. carbonarius and A. alliaceus , were detected in dried chilli powder.

Aflatoxins in cotton seeds and cotton seed cake from Pakistan

ABSTRACTA study was conducted to evaluate the natural occurrence of aflatoxins (AFB1, AFB2, AFG1, AFG2) in cotton seeds (n = 110) and cotton seed cake (CSC; n = 110) from Pakistan. All samples were screened by Enzyme-Linked ImmunoSorbent Assay (ELISA). Positive samples were further quantified by IAC-HPLC-FLD. Total contamination frequency and aflatoxins mean levels were 80% and 69 μg/kg in cotton seeds and the corresponding values for cotton seed cake 88% and 89 μg/kg, respectively. Aflatoxin B1was found in all positive samples and co-occurred with AFB2, AFG1, and AFG2. Sixty-four cotton seeds and 71 CSC samples contained aflatoxins levels higher than the ML set for animal feed (20 µg/kg). The results of the present study will help the regulatory authorities to formulate strategies for monitoring aflatoxins in animal feeds.

Natural occurrence of aflatoxins and ochratoxin A in meju and soybean paste produced in South Korea

In this study, we investigated the occurrence of aflatoxins (AFs) and ochratoxin A (OTA) in meju and soybean paste produced in South Korea. Samples were collected from three regions divided on the basis of climate in South Korea. A total of 100 meju samples were analyzed over 3 years (2012–2015), and 45 soybean paste samples were analyzed in 2016. Mycotoxins were extracted with an immunoaffinity column method and quantified by high-performance liquid chromatography. AFs were detected in 10 of meju (10%) and 11 of soybean paste samples (24.4%) with concentrations of 0.2–48.3 μg/kg and 0.88–16.17 μg/kg, respectively. OTA was detected in 50 of meju (50%) and 22 of soybean paste samples (48.9%) with concentrations of 0.1–193.2 μg/kg and 0.88–26.29 μg/kg, respectively. Mycotoxin contamination in meju was more common in the central region than in the southern areas. Thus, more mycotoxins were produced in the central region owing to less fungal competition in meju during fermentation inside households. We also found that about 91% of AFs and 73% of OTA in meju were degraded after the production of soybean paste and soy sauce. Even after degradation of AFs and OTA, the levels of AFB1 and OTA were 0.5 µg/kg and 7.5 µg/kg in soy sauce and 11.9 µg/kg and 190.4 µg/kg in soybean paste, respectively. Thus, our results suggest the need for constant monitoring of meju and soybean paste for AFs and OTA.

Crambe (Crambe Hispanica Subsp. Abyssinica) Grains Mycobiota and Natural Occurrence of Aflatoxins, Ochratoxin A, Fumonisin B1 and Zearalenone

Crambe (Crambe Hispanica Subsp. Abyssinica) Grains Mycobiota and Natural Occurrence of Aflatoxins, Ochratoxin A, Fumonisin B1 and Zearalenone

Natural occurrence of Aflatoxins in commercial pepper in Iran

ABSTRACTDuring the period from September to November 2014, occurrences of Aflatoxin B1, B2, G1, and G2 (AFB1, AFB2, AFG1, and AFG2) were determined in 76 pepper samples consisting black pepper (n = 40) and red pepper (n = 36) obtained from local markets of Isfahan province, Iran. Aflatoxins' (AFs') analyses were carried out by using the high-performance liquid chromatography (HPLC) method. AFB1 levels in 32 (88.9%) of 36 red pepper samples were higher than the Iranian and European maximum permitted level (>5 µg/kg). Total AFs were detected in 41 out of 76 samples (53.9%) while 25 pepper samples (32.9%) had levels of the toxin above the Iranian and European permitted level, that is, 10 μg/kg. This study shows that incidence of AFs' contamination in red pepper in Iran was significantly higher than black pepper (p < .05) and indicates a serious hazard for human health.

Natural occurrence of aflatoxins in dry fruits and edible nuts

A total 307 samples of dry fruits and edible nuts from Northern areas and Khyber Pakhtunkhwa, Pakistan were evaluated for the presence of aflatoxins (AFs). The samples were analysed using a reversed phase HPLC, equipped with fluorescence detector. Results have revealed that 132 out of 307 samples of dry fruits and nuts were found positive with aflatoxin B1 (AFB1) and total AFs. The highest mean level of total AFs i.e. 7.89 ± 0.99 μg/kg was found in peanuts without shell and lowest mean level (2.45 ± 0.11 μg/kg) was found in watermelon seeds without shell samples. Samples 75 (24%) were found contaminated with AFB1, ranged from 8 to 10 μg/kg and 41 (13%) samples were found above the level of 10 μg/kg for total AFs. The high occurrence of AFs may cause health hazards for consumers and limit exports.

Natural occurrence of aflatoxins and ochratoxin A in processed spices marketed in Malaysia

The analysis of aflatoxins (B1, B2, G1 and G2) and ochratoxin A (OTA) was performed in processed spices marketed in Penang, Malaysia, using immunoaffinity columns and HPLC equipped with fluorescence detector (HPLC-FD). The processed powdered spices analysed include dried chilli, fennel, cumin, turmeric, black and white pepper, poppy seed, coriander, ‘garam masala’, and mixed spices for fish, meat and chicken curry. Two different studies were carried out. The limit of detection (LOD) was 0.01 ng g−1 for each aflatoxin (AF) and 0.10 ng g−1 for OTA (signal-to-noise ratio = 3:1). In the first study, 34 commercial processed spices analysed with a mean level, range and incidence of positive samples for total AF were 1.61 ng g−1, 0.01–9.34 ng g−1 and 85%, respectively, and for AFB1 were 1.38 ng g−1, 0.01–7.68 ng g−1 and 85%, respectively. The mean level, range and incidence of positive samples for OTA were 2.21 ng g−1, 0.14–20.40 ng g−1 and 79%, respectively. Natural co-occurrence of AF and OTA was found in 25 (74%) samples. In the second study of 24 commercial processed spices, the mean level, range and incidence of positive samples for total AF were 8.38 ng g−1, 0.32–31.17 ng g−1 and 88%, respectively, and for AFB1 were 7.31 ng g−1, 0.32–28.43 ng g−1 and 83%, respectively. Fifteen positive samples for total AF and two positive samples for OTA exceeded the permissible Malaysian limit of 5 ng g−1. Contamination of both mycotoxins in spices may represent another route of exposure to consumers due to their frequent and prolonged consumption, as spices are common ingredients in popular dishes among Asian countries.

Mycobiota in Camel Fodder and Natural Occurrence of Aflatoxins in Saudi Arabia

The purpose of this study was to deter-mine the contamination of aflatoxigenic fungi in camel fodder. The results indicated that the fun-gi detected were almost the same but differed in the percentage of incidence. Alternaria alternata, A. solani, A. tennius, Aspergillus niger, A. flavus, A. ochraceoroseus, A. oryzae, A. parasiticus, A. japonicus, A. carbonarius, Fusarium solani, F. ox-ysporum, F. semitectum, F. ventricosum, Helmin-thosporium sativum, H. Carbonum, Mucor ja-vanicus, Phoma herbarum, Rhizopus oryzae, Rhi-zopus japonicas, Trichoderma harzianum, Peni-cillium funiculosum and R. solani were isolated from different camel fodder. A highest amount of aflatoxins were obtained in Rhodes grass (15.577μg/100g) followed by compound feed (6.687μg/100g) and barley (5.453μg/100g). Twenty nine aflatoxigenic fungi isolated fodder, most isolates were capable of producing detect-able levels of some types AFs. The highest amount of total AFs (5.904μg/100ml) was recov-ered from a culture of A. parasiticus (isolate 3-T6) followed by (5.244μg/100ml) was obtained from A. flavus (isolate 20-R5).

Natural Occurrence of Aflatoxins in Peanuts and Peanut Butter from Bulawayo, Zimbabwe

Mycotoxins are toxic secondary metabolites produced by filamentous fungi that may contaminate food and pose a health risk, especially in developing countries, where there is a lack of food security and quality is subsumed by food insufficiency. Aflatoxins are the most toxic known mycotoxins and are a significant risk factor for liver and kidney cancer, teratogenicity, undernutrition, and micronutrient malabsorption in both humans and animals. The main aim of the study was to determine the extent of fungal and aflatoxin contamination in peanuts and peanut butter being sold in both the formal and informal markets in Bulawayo, Zimbabwe. Eighteen peanut samples and 11 peanut butter samples were purchased from retail shops and the informal market. Fungal contamination was determined using standard mycology culture methods, while aflatoxin contamination was determined using high-performance liquid chromatography-fluorescence detection. Four of the six peanut samples tested for fungal contamination were infected with Aspergillus flavus/parasiticus, ranging from 3 to 20% of the kernels examined, while 27% (3 of 11) of the peanut butter samples were infected with A. flavus/parasiticus. Ninety-one percent (10 of 11) of the peanut butter samples were contaminated with aflatoxins (mean, 75.66 ng/g, and range, 6.1 to 247 ng/g), and aflatoxin B1 was the most prevalent (mean, 51.0 ng/g, and range, 3.7 to 191 ng/g). Three of the 18 peanut samples were contaminated with aflatoxins (range, 6.6 to 622 ng/g). The commercial peanut butter samples had very high aflatoxin levels, and manufacturers should be sensitized to the detrimental effects of aflatoxins and measures to reduce contamination.

Transport via xylem and accumulation of aflatoxin in seeds of groundnut plant

Aflatoxin contamination in groundnut seeds in the absence of any aflatoxigenic fungi leads to a hypothesis that aflatoxins are present naturally in soil and is transferred to seeds through uptake by roots. A survey was conducted on the natural occurrence of aflatoxins in agricultural soils, among nine main groundnut-growing regions of Karnataka state, India. All 71 soil samples collected in this survey were contaminated with aflatoxins esp. AFB1. An in vitro xylem sap experiment proved the ability of groundnut plant roots to absorb AFB1, and transport to aerial plant parts via the xylem. Hydroponics experiment also proved the uptake of AFB1 by the roots and their translocation to shoot. Uptake was affected by the initial concentration of toxin and pH of the medium. Among the 14 varieties screened, GPBD4 and MLT.K.107 (III) recorded highest and least AFB1 uptake, respectively. The above results were validated using a greenhouse experiment. Here, the aflatoxin absorbed by root gradually transferred to shoot that was later found in seeds towards the end of experiment. Thus, the groundnut seeds can also get contaminated with aflatoxin by direct uptake of aflatoxin through conducting tissue in addition to fungal infection. The present study revealed the novel mode of aflatoxin contamination in groundnut seeds without fungal infection.

Mycobiota and natural occurrence of aflatoxin, deoxynivalenol, nivalenol and zearalenone in rice freshly harvested in South Korea

The natural fungal mycobiota and contamination by aflatoxins (AFs), deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEN) in rice from six locations (80 farms) in South Korea were surveyed during the harvest year 2010. Mycological analysis indicated that Fusarium was the predominant fungal genera, followed by Penicillium, Phoma, Myrothecium, and Cladosporium spp. Within the genus Fusarium, Fusarium graminearum was found most frequently. Polymerase chain reaction analysis targeting the AFs (aflR, omtB, ver-1 and omtA), DON/NIV (tri4, tri5, tri5–tri6, tri7 and tri13) and ZEN (pks4) biosynthetic genes showed that potential ZEN and NIV producers were the most prevalent. A similar trend was observed for the natural occurrence of all four mycotoxins. In both white and brown rice, ZEN was the main mycotoxin contaminant (range 0.4–95.4μg/kg), followed by NIV; AFs and DON were not prevalent. The present study provides a detailed description of the fungi and natural occurrence of these four mycotoxins in rice at harvest, which may help in understanding the population dynamics and in developing effective control measures.

Natural occurrence of aflatoxin, aflatoxigenic and non-aflatoxigenic Aspergillus flavus in groundnut seeds across India

A survey across different agro-climatic regions of India was done and 38 groundnut seed samples were collected from various sources. Upon analysis, all samples were found infected with Aspergillus flavus ranging from 2 to 50% incidence with aflatoxin content of 0.0 to 28 ppb. Greenhouse studies revealed no correlation between incidence of A. flavus and aflatoxin content on seedling emergence, root length, shoot length and dry weight. Seeds were predominantly contaminated with aflatoxin B1 followed by aflatoxin B2. Among the tested A. flavus isolates, 31 were found aflatoxigenic and seven were nonaflatoxigenic when analyzed through cultural, thin layer chromatography, competitive direct enzyme linked immunosorbent assay and multiplex polymerase chain reaction. Present study reveals the current scenario of aflatoxin contamination, and aflatoxigenic and non-aflatoxigenic fungal infection in groundnut seeds collected across India. Keywords: Polymerase chain reaction (PCR), Aspergillus flavus , aflatoxin, enzyme-linked immuno sorbent assay (ELISA), groundnut African Journal of Biotechnology Vol. 12(19), pp. 2587-2597

Natural occurrence of aflatoxins in maize harvested in Serbia during 2009–2012

The aim of the present study was to determine concentration of aflatoxins (AFs) B1, B2, G1 and G2 in 380 maize samples collected from different regions of Serbia during four years period and to analyze the influence of weather conditions on the AFs production.Aflatoxins content was determined by direct competitive Enzyme Linked Immunosorbent Assay (ELISA) method.In 180 maize samples analyzed in 2009–2011 period AFs were not detected. However weather condition changes in 2012 caused AFs presence in 137 (68.5%) of samples in the concentration range from 1.01 to 86.1 μg/kg with the mean level of 36.3 μg/kg.The obtained results indicate great influence of hot and dry weather with prolonged drought during spring and summer 2012 on a contamination of maize with AFs.Since the obtained results present the first national report of AFs maize contamination this study could be of a great interest for establishing monitoring programs of AFs in Serbia.

Natural occurrence of aflatoxin in green leafy vegetables

Natural occurrence of aflatoxin (AF) in agricultural soils, green leafy vegetables (GLVs) and persistence in processed foods was investigated. in total 33 soil samples and 81 GLVs which belonged to 9 groups collected from nine vegetable-growing regions were studied. Seventy percent of soils and 69.2% GLVs were contaminated with AF ranging from 0.0 to 88ppb. Root samples frequently had higher concentration of AFB1 in comparison with shoot samples. Under greenhouse conditions all the tested plants were found to take up AF. From xylem and phloem sap experiments it was clear that AF was gaining entry into the plant system via water-conducting xylem tissue and was translocated to aerial plant parts, with subsequent entry into the phloem. Of the two cooking methods studied, pressure cooking of GLVs significantly reduced the AF level in comparison with ordinary boiling.

Natural occurrence of aflatoxins and ochratoxin A in commercial chilli and chilli sauce samples

Total 170 samples of chillies (chilli sauce, crushed chilli and powdered chilli) were analyzed by HPLC coupled with fluorescence detector. AFs were detected in 39, 59 and 56% of chilli sauce, crushed chilli and chilli powder samples from open market compared with 29, 54 and 58% samples respectively, from food restaurants. OTA was found 5 (19%), 11 (38%) and 13 (38%), in chilli sauce, crushed chilli and chilli powder from open market compared to 4 (17%), 14 (50%), and 12 (41%) samples respectively, from food restaurants. About 12, 27 and 35% chilli sauce, crushed chilli and powdered chilli samples from open market were found above the European Union (EU) limit for total AFs compared to 8, 32, and 41% samples from food restaurants. The daily intakes of AFs and OTA were 3.3 and 2 μg/kg, respectively.

Natural occurrence of aflatoxins in groundnut (Arachis hypogaea L.) from eastern Ethiopia

Aflatoxins are highly toxic and carcinogenic chemical substances produced by Aspergillus spp. on variety of agricultural commodities including groundnut. This study was conducted with the objective to assess total aflatoxin concentration in groundnut samples. One hundred and twenty groundnut samples collected from farmers' stores and markets were used for aflatoxin analysis in an ELISA test. Of these, 93 were positive while the remaining 27 were negative. The total aflatoxin levels in the positive samples varied between 15 μg/kg and 11,900 μg/kg. The current results clearly revealed heavy contamination of groundnut samples in Ethiopia, which is far beyond the Food and Agricultural Organization of the United Nations/World Health Organization (FAO/WHO) standard (15 μg/kg) and the European Union (EU) limit i.e. 4–15 μg/kg, depending on the end use of groundnut, suggesting the urgent need to apply control measures against toxicogenic fungi and associated mycotoxins. The major factors for contamination of groundnuts by aflatoxin were suggested to be pre- and post-harvest environmental factors, and poor management practices including delayed harvesting, mechanical damage at the time of harvesting, and limited curing and drying before storage.