Fungal profile, levels of aflatoxin M1, exposure, and the risk characterization of local cheese 'wagashi' consumed in the Ho Municipality, Volta Region, Ghana

Wagashi is a West African type cottage cheese locally prepared from cow milk. Wagashi like other milk products, is prone to microbial contamination, particularly by fungi. Many of these fungal species produce mycotoxins which are of serious public health concern. This work aimed to update the mycoflora profile and determine the concentrations of aflatoxin M1 and its health risk characterization due to the consumption of wagashi. Culturing the wagashi on mycological media (Oxytetracycline Glucose Yeast Extract OGYE, Dichloran Rose Bengal Chloramphenicol DRBC) caused a de-novo growth of the quiescent spores at 28-30 °C for 5-7 days. The analysis of AFM1 levels in the samples was done using High-Performance Liquid Chromatography connected to a Fluorescence detector (HPLC-FLD). The exposure and risk assessment to the AFMI levels were determined using deterministic models prescribed by the European Food Safety Authority (EFSA). The fungal counts ranged between 2.36-4.30 log10 CFU/g. In total, thirteen (13) fungal species from eight (8) genera were isolated from all wagashi samples. They are; Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, Fusarium verticillioides, Penicillium digitatum, Trichoderma harzianum, Aspergillus terreus, Rhodotorula mucilaginosa, Rhizopus stolonifer, Aspergillus fumigatus, Yeast sp., Mucor racemosus and Fusarium oligosporum belonging to the genera Fusarium, Aspergillus, Penicillium, Trichoderma, Rhodotorula, Rhizopus, Yeast, and Mucor. The AFM1 observed in the wagashi samples' analysis was low, ranging from 0.00 (Not Detected) ± 0.00 - 0.06 ± 0.002 µg/Kg. Risk assessments of AFM1 using deterministic models produced outcomes that ranged between 5.92 × 10-3- 0.14 ng/kg bw/day, 1.42 -44.35, 0-0.0323 ng aflatoxins/kg bw/day, and 1.51 × 10-3 - 9.69 × 10-4 cases/100,000 person/yr for estimated daily intake (EDI), margin of exposure (MOE), average potency, and cancer risks, respectively, for the age categories investigated. Fungal counts were interpreted as medium to high. It was also established that the consumption of wagashi may pose adverse health effects on all age categories in the selected zones of the study since all calculated MOE values were less than 100,000.

Characterization and fungicide sensitivity of Trichoderma species causing green mold of Ganoderma sichuanense in China

Green mold disease, caused by Trichoderma spp., is one of the most devastating diseases of mushrooms in China. The application of fungicides remains one of the important control methods among the integrated pest management tools for disease management in mushroom farms. This study aimed to identify Trichoderma spp., isolated from G. sichuanense fruiting bodies displaying green mold symptoms collected from mushroom farms in Zhejiang, Hubei, and Jilin Province, China, and evaluate their in vitro sensitivity to six fungicides. A total of 47 isolates were obtained and classified into nine Trichoderma spp. namely, T. asperellum, T. citrinoviride, T. ganodermatiderum, T. guizhouense, T. hamatum, T. harzianum, T. koningiopsis, T. paratroviride, and T. virens, through morphological characteristics and phylogenetic analysis of concatenated sequences of translation elongation factor 1-alpha (TEF) and DNA-dependent RNA polymerase II subunit (RPB2) genes. The pathogenicity test was repeated two times, and re-isolation of the nine Trichoderma spp. from the fruiting bodies of G. sichuanense fulfilled Koch's postulates. Prochloraz manganese showed the best performance against most species. This research contributes to our understanding of green mold disease, reveals the phylogenetic relationships among Trichoderma species, and expands our knowledge of Trichoderma species diversity associated with green mold disease in G. sichuanense.

Survey of knowledge, and attitudes to storage practices preempting the occurrence of filamentous fungi and mycotoxins in some Ghanaian staple foods and processed products

Mycotoxigenic fungi can infect and produce potent mycotoxins in foodstuffs prior to harvest, during harvest (field fungi), and in storage after harvest (storage fungi), which when ingested, can result in adverse health effects. This study was aimed at assessing the knowledge, attitudes, and practices adopted by the Ghanaian populace to help mitigate the occurrence of molds and mycotoxins in foods. A cross-sectional survey involving a structured questionnaire was conducted with 642 respondents from twelve regions of Ghana. Descriptive statistics and analyses of variance were calculated. Correct Classification Rate (CCR) was measured to assess the utility of a logistic regression model. The results of the study showed that the majority of 299 (46.6%) of the respondents were between the ages of 18-25. Age and educational level were related to knowledge about the occurrence of fungi and mycotoxins in foods (p < 0.05). More than half the respondents, 50% indicated that they knew of aflatoxins as a major mycotoxin present in food. Higher education directly influenced on the knowledge of mycotoxicosis and the management of stored food to present intoxication by fungal metabolites. 502 (32.9%) knew that consuming foods with toxins could cause stomach aches. The most commonly consumed food commodity despite the presence of visible growth of fungi was bread (35.3%). The average KAP score for knowledge showed that, out of 100%, there was adequate knowledge (63.8%) among the members of the Ghanaian populace. Favorable environmental conditions of high humidity (> 85% ERH) and temperature (> 28-32 °C) enhance the proliferation of fungi in most foods and the attendant production of mycotoxins such as aflatoxins, ochratoxins, and fumonisins are associated with several severe human and animal health conditions; mycotoxicosis was associated with high fever, pain, vomiting, suppression of immunity, cancer, etc. when these foods are consumed on regular basis for a prolonged length of time. Future examination of the food items used for the School Feeding Programme in Ghana will offer opportunities to examine the risks of feeding youth with fungal-contaminated food preparations from providers.

Valorization of agro-industrial wastes into animal feed through microbial fermentation: A review of the global and Ghanaian case

Agricultural and industrial activities around the world lead to the production of large quantities of agro-industrial wastes (e.g., peels of cassava, pineapple, plantain, banana, and yam, as well as rice husks, rice bran , corn husks, corn cobs, palm kernel cake, soybean meal, wheat bran, etc.). These agro-industrial wastes are discarded indiscriminately, thereby polluting the environment and becoming hazardous to human and animal health. Solid-state fermentation (SSF), a microbial fermentation process, is a viable, efficient approach that transforms discarded agro-industrial wastes into a plethora of useful value-added bioproducts. There is growing interest in the application of SSF in valorizing agro-industrial wastes for the production of fermented, protein-rich animal feed within the livestock industry. SSF reduces anti-nutritional factors whose presence hinders the digestibility and bioavailability of nutrients in agro-industrial wastes. Thus, the application of SSF improves the nutrient contents and quality of valorized agro-industrial wastes as animal feed. Fermented animal feed production may be safer, cheaper and enhance the overall growth performance and health of animals. SSF, therefore, as a strategic approach in a circular bioeconomy, presents economic and practical advantages that guarantee efficient recycling and valorization of agro-industrial wastes that ameliorate environmental pollution. This paper reviews the status of global and local Ghanaian biotransformation and valorization of agro-industrial wastes through SSF for the production of nutrient-rich animal feed.

Toxicogenic fungal profile, Ochratoxin A exposure and cancer risk characterization through maize (Zea mays) consumed by different age populations in the Volta region of Ghana

Maize (Zea mays) is an important staple food crop for the majority of Ghanaians. Maize is mostly contaminated by fungal species and particularly mycotoxins. This work aimed to identify and quantify the incidence of fungal infection and exposure to Ochratoxin A (OTA) as well as the health risk characterization in different age populations due to maize consumption in the Volta region. Maize samples were plated on Dichloran Rose Bengal Chloramphenicol (DRBC) agar, and Oxytetracycline Glucose Yeast Extract (OGYE) agar. All media were prepared in accordance with the manufacturers' instructions. The plates were incubated at 28 ± 2 °C for 5-7 days. High-Performance Liquid Chromatography connected to a fluorescence detector (HPLC-FLD) was used to analyze the ochratoxin A (OTA) levels in maize. Cancer risk assessments were also conducted using models prescribed by the Joint FAO/WHO Expert Committee on Additives (JECFA). The maize samples collected from the Volta region contained fungal population between the range of 3.08-4.58 log10 CFU/g. Eight (8) genera were recorded belonging to Aspergillus, Trichoderma, Penicillium, Fusarium, Saccharomyces, Mucor, Rhodotorula and Rhizopus. The species diversity includes A. flavus, A. niger, T. harzianum, P. verrucosum, F. oxysporum, Yeast, F. verticillioides, Rhodotorulla sp, A. fumigatus, R. stolonifer, M. racemosus species. Additionally, the ochratoxins level contained in the samples were very noteworthy and ranged from 1.22 to 28.17 μg/kg. Cancer risk assessments of OTA produced outcomes also ranged between 2.15 and 524.54 ng/kg bw/day, 0.03-8.31, 0.0323, and 0.07-16.94 for cases/100,000 person/yr for Estimated Daily Intake (EDI), Margin of Exposure (MOE), Average Potency, and Cancer Risks respectively for all age categories investigated. There was very high mycoflora load on the maize sampled from the Volta region, likewise the range of mycotoxins present in the maize grains, suggesting the potential to pose some adverse health effects with the populace of the Volta region.

Influence of substrate formulation on some morphometric characters and biological efficiency of Pleurotus ostreatus EM-1 (Ex. Fr) Kummer grown on rice wastes and "wawa" (Triplochiton scleroxylon) sawdust in Ghana

A study was conducted to correlate the stipe length, cap diameter, and growth yield (fresh weight) of the fruiting body of Pleurotus ostreatus strain EM-1 using different rice lignocellulosic wastes and "wawa" (Triplochiton scleroxylon) compost: raw unamended rice straw; rice straw amended with 1% CaCO₃ and 10% CaCO₃; rice straw amended with 1% CaCO₃ and 10% CaCO₃ supplemented with 5, 10, and 15% rice bran prior to bagging; rice straw and rice husk mixture (1:1 w/w) amended with 1% CaCO₃ and 10% CaCO₃ supplemented with 5%-15% rice bran prior to bagging; and wawa sawdust amended with 1% CaCO₃ and 10% rice bran. The experiment was laid out in a completely randomized design in a well-ventilated semi-dark room at 26-28°C and 60%-65% ERH. The fresh weight, length of the stipe, and cap diameter increased differentially in each treatment with an increasing period of composting in the substrates. There was a good coefficient of determination (R ²) among stipe length, cap diameter, and biological efficiency (%). The R ² among stipe length, cap diameter, and biological efficiency for the different formulated substrates ranged between R ² = 0.6346-0.9454 and R ² = 0.570-0.9624, respectively. The highest R ² was obtained on raw unamended rice straw substrates (stipe length and cap diameter were R ² = 0.9454 and R ² = 0.9444, respectively), whereas the lowest correlation coefficient among stipe length, cap diameter, and biological efficiency (%) (R ² = 0.6346; R ² = 0.0570), respectively, was recorded on the rice straw and rice husk mixture substrates. The results show a positive correlation in morphometric growth parameters studied on the different formulated substrates.

Mycobiota profile, phenology, and potential toxicogenic and pathogenic species associated with stored groundnuts (Arachis hypogaea L.) from the Volta Region, Ghana

This study updates the mycobiota resident in groundnut seeds, their phenology during storage with the view to ascertain their occurrence, potential toxigenic species, and pathologically important species in the stored samples. The moisture content of the seeds ranged from 5.7% to 6.5% within the stipulated safe moisture content of 8% for extension of shelf life. Culturing the seeds on mycological media (Sabouraud's Dextrose Agar SDA; Oxytetracycline Glucose Yeast Extract OGYE, Potato Dextrose Agar, PDA) caused a de novo growth of the quiescent spores at 28-30°C for 7-14 days. Fungal population counts on the three media ranged from 2.01 to 2.16 log₁₀ CFU/g samples to a final 6-month count of 1.67-2.60 log₁₀ CFU/g. Eighteen different fungal species belonging to ten genera were encountered on the media, namely Aspergillus, Cladosporium, Curvularia, Fusarium, Penicillium, Trichoderma, Rhizopus, Rhodotorula, Sporendonema, and Paecilomyces. Aspergillus spp. (A. niger, A. flavus, A. fumigatus, and A. terreus) were the most frequently isolated, followed by Fusarium species (F. oxysporum, F. solani, and F. verticillioides), Trichoderma (T. harzianum and T. viride), Rhizopus spp (R. oligosporus and R. stolonifer), and Penicillium verrucosum. The species which were seed borne (A. niger, A. flavus, A. terreus, A. fumigatus, F. solani, F. verticillioides, T. viride, C. herbarum, and Curvularia lunata) were isolated on both surface sterilized and non-surface sterilized seeds. The phenology of the encountered fungal species generally followed five patterns. The most frequently isolated Aspergillus niger, A. flavus, and A. fumigatus predominated throughout the 6 months sampling period, while A. ustus and A. terreus appeared sporadically and disappeared. The early colonizers (R. oligosporus, R. stolonifer, and Paecilomyces) could not be isolated after 2-3 months owing presumably to stronger antibiosis competition from the Aspergillus species. The most predominant Aspergillus species initially constituted 36%-48% of the total population but declined to 10%-36% in 6 months. Mycobiota encountered with mycotoxigenic potential and human health importance were A. niger, A. flavus, A. fumigatus, F. verticillioides, and Penicillium verrucosum. Other species of pathological importance to plants were Curvularia lunata and Fusarium oxysporum. The practical implications of these findings are discussed.

Use of Pleurotus eous Strain P-31 Spent Mushroom Compost (SMC) as Soil Conditioner on the Growth and Yield Performance of Capsicum annuum L. and Solanum lycopersicon L. Seedlings under Greenhouse Conditions in Ghana

The objective of this study was to investigate the influence of spent mushroom compost of Pleurotus eous strain P-31 on the growth and yield performance of pepper and tomato seedlings under greenhouse conditions. Sandy loam soil was combined with different percentages of SMC to obtain the following combinations (0, 5, 10, 15, 20, 25 and 30) %. Lower concentrations SMC₅, SMC₁₀ and SMC₁₅ promoted vegetative growth (plant height, leaf area, chlorophyll content, number of leaves and axillary branches) of the two test plants. Tomato seedlings grown in SMC₁₀ recorded the highest plant height (50.3 ± 7.2cm); leaf area (378.8 ± 1.2cm²); number of floral buds (51) and flowers (28) whereas SMC₅ recorded the highest chlorophyll content 34.1 ± 0.9CCI though SMC₁₅ recorded the highest number of leaves (8). Tomato seedlings grown in SMC₃₀ produced both the maximum number of fruits (8) with corresponding high weight (34.2 ± 7.7g). Pepper seedlings grown in lower concentrations (SMC_5–15) recorded the highest plant heights (29.8–30.8cm), chlorophyll content (20.3CCI) and leaf area (53.5–66.2 cm²). Although the different combinations of sandy loam soil and SMC did not significantly (p ≥ 0.05) affect the number of axillary branches developed; different combinations significantly (p ≤ 0.05) affected the number of floral bud, flower and fruit, weight of fruits formed and value of each of these increased with increasing percentage of SMC. Pepper seedlings grown on SMC₃₀ recorded the maximum number of floral buds (32.0 ± 3.6), number of flowers (19.4 ± 1.3), number of fruits (10.8 ± 1.2) and weight of fruits (31.9 ± 3.4g). Tomato seedlings raised on SMC₁₀₀ (spent mushroom compost only) and soil only did not significantly (p ≥ 0.05) differ from each other however, was statistically significant (p ≤ 0.05) from amended sandy loam soil by all criteria investigated. The study shows that SMC provide favourable soil conditioners for the cultivation of fruits, vegetables and foliage crops as it improved growth and yield of tomato and pepper seedlings.

Mycofloral profile and the radiation sensitivity (D10 values) of solar dried and gamma irradiated Pleurotus ostreatus (Jacq.Ex. Fr.) Kummer fruitbodies stored in two different packaging materials

The presence of fungi in our foods poses serious health risks as some genera of fungi may produce certain mycotoxins which have carcinogenic, mutagenic, teratogenic, and immunosuppressive effect on humans and animals alike. Fruitbodies of Pleurotus ostreatus were solar dried at a moisture content of 12.5 ± 0.2% and stored in polythene and polypropylene packs, gamma irradiated at doses of 0 (control), 1, 2, 3, 4, and 5 kGy at a dose rate of 1.7 kGy/hr from a Cobalt 60 source (SLL, 515, Hungary) and stored at room temperature 28-30°C for a period of 12 months. Mycological analyses were done at intervals of 0, 3, 6, and 12 months. A total of eleven (11) fungi belonging to eight fungal genera were isolated on both Cooke's and DRBC media; Aspergillus (A. niger, A. flavus, A. fumigatus, A. tamarii), Rhizopus (R. oligosporus), Mucor (M. racemosus), Fusarium (F. oxysporum), Penicillium (Penicillium sp.), Trichoderma (T. viride), and Rhodotorula sp. were recorded. There was a significant (p < .05) reduction in initial mycofloral population by an average of 2.2 log cycles as well as in species numbers with increasing doses of radiation. Radiation sensitivity (D₁₀ values) also ranged between 1.68-2.78 kGy. Gamma irradiation treatment is one way which can enhance food safety through the reduction in potential pathogens and has been recommended as part of a comprehensive program to enhance food safety.

Influence of low dose of gamma radiation and storage on some vitamins and mineral elements of dried oyster mushrooms (Pleurotus ostreatus)

Mushrooms contain some of the most potent natural medicines on the planet. Vitamins A, C, D, Mineral elements, contents, as well as total soluble solids (Brix^o) of dried composition of Pleurotus ostreatus were investigated after exposing to gamma radiation doses of 0 (control), 0.5, 1, 1.5, and 2 kGy at a dose rate of 1.7 kGy per hour in air from a Cobalt 60 source (SLL 515, Hungary) batch irradiator prior to storage (0 month) and after storage (12 months) at room temperature (28 ± 2°C). Results obtained showed some significant (p < .05) differences due to irradiation and storage. Before storage, vitamins A, C, and D contents of dried and irradiated mushrooms ranged 0.003 ± 0.08-0.014 ± 0.08, 0.042 ± 1.06-0.132 ± 1.06, and 0.040 ± 0.76-0.057 ± 0.76 mg/g, respectively. After 12 months, vitamin contents decreased and ranged 0.0029 ± 0.08-0.010 ± 0.08, 0.038 ± 1.06-0.125 ± 1.06, and 0.031 ± 0.76-0.05 ± 0.76 mg/g for vitamins A, C, and D, respectively. Total soluble solids recorded 1.5 Brix^o, however, showed no significant difference (p > .05) and did not change in 12 months after gamma irradiation up to 2 kGy. Sodium ranged from 14.00 ± 0.7 to 14.90 ± 0.8 mg/100 g. Potassium content varied from 30.20 ± 0.5 to 33.10 ± 0.6 mg/100 g. Magnesium content ranged 1.27 ± 0.15-3.53 ± 0.04 mg/100 g. Calcium ranged 11.00 ± 0.4-12.53 ± 0.4 ± 0.03 mg/100 g. Phosphorus content ranged 6.11 ± 0.30-6.41 ± 0.35 mg/100 g, whereas Nitrogen content was found to be 3.00 ± 0.03-3.60 ± 0.25 mg/100 g. Microelements or heavy metals included Copper; detected ranged 0.00 ± 0.00-0.02 ± 0.001 mg/100 g, Zinc content ranged 0.01 ± 0.002-0.03 ± 0.001 mg/100 g. Iron content was found to be in the range 0.29 ± 0.01-0.37 ± 0.1 mg/100 g. Manganese content was found to be in the range 0.03 ± 0.001-0.04 ± 0.01 mg/100 g. Lead content was found to be 0.00 ± 0.00-0.03 ± 0.001 mg/100 g. Food processing and storage has the potential to slightly alter the stability of vitamins in foods. Pleurotus ostreatus showed appreciable levels of mineral elemental composition, essential vitamins A, C, and D, and can be endorsed as a natural medicinal food product in the food and pharmaceutical industries. The heavy metals detected were with also below the upper limits permissible by the WHO standards and is thus safe for human consumption.