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Black soldier fly larvae (BSFL) bioconversion is a promising bioprocessing technology. However, one major challenge in BSFL waste processing, is that agri-food wastes (e.g. animal manure, agricultural crops and residues) tend to be low in macronutrients and high in lignocellulosic fibre (e.g. cellulose, hemicellulose and lignin), resulting in longer larvae development times and lower larval mass compared to when reared on high-value substrates (e.g. food waste). This study aimed to increase BSFL process performance on four fibre-rich substrates by ammonia substrate pretreatment: brewers spent grain, grass clippings, oat drink-by-product and cow manure. We first conducted experiments to identify optimal aqueous ammonia dose (1 vs 5%, 25% conc.) and pretreatment time (3 vs 7 days) by comparing its effect on the lignocellulosic substrate composition (neutral, acid and lignin detergent fibre) compared to an untreated control. Once we determined the optimal pretreatment condition, we completed controlled feeding experiments with four replicates, using ammonia pretreated and untreated substrates in a climate chamber (9 days, 2.5 larvae/cm2, 28 °C and 44-70% relative humidity). Results demonstrated that for most substrates a dose of 5% achieved improved lignocellulosic degradation, decreasing neutral detergent fibre by 6 to 22%, when compared to the untreated control. A pretreatment time of 3 days performed best for all substrates, except grass clippings, which demonstrated better results at 7 days. Based on our results, aqueous ammonia can result in fibre degradation of BSFL substrates and influence larvae performance. Although not fully evident at this stage of the experiments, ammonia pretreatment of such fibrous wastes shows mixed results of larvae performance depending on the substrates in question. This research works to increase performance of abundant fibrous low-value waste streams for recycling within the food system. ISSN:2352-4588

One of the major barriers for market entry of edible insects and insect-derived products is product safety. Insects have a high and diverse microbial community, mainly influenced by the food and rearing environment. Consequently, reliable post-processing treatment techniques are needed to produce safe insects/insect-derived products. Common treatment techniques such as heating can lower the nutritional value and product quality. In contrast, low-energy electron beam (LEEB) is an emerging gentle non-thermal treatment technique to maintain the product quality and commercial value. However, its potential application as an insect post-processing treatment step has not yet been investigated. To the authors knowledge, this is the first study that evaluated the use of LEEB as a further treatment step for dried black soldier fly larvae (BSFL) and mealworms (MW). BSFL and MW were sourced from two insect producers. Following harvesting, insects were blanched (BSFL: 80 °C, 2 min; MW: 95 °C, 3 min) and dried (BSFL: 80 °C, 27 h; MW: 90 °C, 3.5 h). Insects were then treated with LEEB in triplicate (250 keV, 12 kGy). The effectiveness of the LEEB treatment was evaluated in comparison to a control (without LEEB). Physical (water activity, moisture content) and microbial parameters (aerobic and anaerobic counts/spores) were determined directly after treatment and monthly in a six-month controlled shelf-life study (24 °C, 65% RH). LEEB was effective in reducing numbers of all microbial parameters in MW. Specifically, aerobic and anaerobic counts in MW were both reduced by approximately 4-log10 colony forming units per gram (cfu/g). Likely due to the longer drying duration (27 vs 3 h), LEEB treatment had a lower effect on BSFL microbial numbers, an approximate 1-log10 cfu/g reduction for aerobic and anaerobic counts. In summary, LEEB can be an effective and gentle processing step to ensure product safety within the insect industry. ISSN:2352-4588

ISSN:1382-6077

ISSN:1382-6077

Black soldier fly larvae, Hermetia illucens L., (BSFL) convert organic waste material into insect biomass, which can then be processed into a profitable and sustainable protein and fat ingredient in animal feeds. In areas where sanitation remains a challenge, the potential to valorise fecal waste material, using the BSFL technology would increase stakeholder participation in improving sanitation and encourage entrepreneurial opportunities. However, remaining barriers still exist, such as product safety. Therefore, the main objectives of this study were to evaluate BSFL development on varying ratios and combinations of differing types of human fecal waste and organic waste material, and to assess if the use of a novel non-thermal treatment technology, low energy electron beam (LEEB), could lead to safe BSFL products. The first part of the study was conducted in Durban, South Africa, where a public private partnership exists between the Ethekwini Municipality and The BioCycle, to innovatively manage fecal sludge from urine diversion toilets (UD). However, BSFL develop poorly on UD fecal sludge, due to the low nutritional quality. Therefore, the substrates tested in this study were: UD fecal sludge, ventilated improved pit latrine fecal sludge (VIP), primary sludge (PS), restaurant food waste (FW), and brewers’ spent grain (SG). To evaluate this, BSFL development (mass), survivability, bioconversion and waste reduction efficiency were measured. Four-day old BSFL were reared on 250 g wet mass of the specified substrate at the start of the experiment, based on an assumed feeding rate of 100 mg of substrate larvae-1day-1. Experiments were conducted under controlled environmental conditions with a temperature of 30 ± 2°C and relative humidity of 60 ± 5 % for 11 days. Results demonstrated BSFL grown on the substrate combination of 37.5% PS, 37.5% VIP and 25% FW (% m/m) had a high dry bioconversion rate of 18.69 ± 2.11% compared to 3.33 ± 2.78% on 100% VIP. To effectively inactivate pathogens that may be present in BSFL reared on human fecal waste, BSFL were inoculated with Escherichia coli (E. coli, strain K-12 MG1655) and passed through continous LEEB at a specified dose to achieve a 3 to 5-log10 inactivation. The attractiveness of using this non-thermal treatment technology is the potential in reducing microbial concentrations without product damage, in addition to extending the shelf life.

As the world population increases, food demand and agricultural activity will also increase. However, approximately 30 – 40% of the food produced today is lost or wasted along the production chain. Increasing food demands would only intensify the existing challenges associated with agri-food waste management. An innovative approach to recover the resources lost along the production chain and convert them into value-added product(s) would be beneficial. An alternative solution is the use of the larvae of the black soldier fly (BSFL), Hermetia illucens L., which can grow and convert a wide range of organic waste materials into insect biomass with use as animal feed, fertilizer and/or bioenergy. However, the main concern when creating an economically viable business is the variability in BSFL bioconversion and processing due to the variability of the substrate. Many factors, such as the nutritional composition of the substrate heavily impact BSFL development. Another concern is that substrates with high lignin and cellulose contents have demonstrated poor digestibility by BSFL. Studies suggest that pretreatment methods may improve the digestibility and biodegradability of the substrate by BSFL. However, a systematic review of existing pretreatment methods that could be used for enhancing the bioconversion of these wastes by BSFL is lacking. This paper provides a state-of-the-art review on the potential pretreatment methods that may improve the digestibility of substrates by BSFL and consequently the production of BSFL. These processes include but are not limited to, physical (e.g., mechanical and thermal), chemical (alkaline treatments), and biological (bacterial and fungal) treatments., Frontiers in Sustainable Food Systems, 5, ISSN:2571-581X

As the world population increases, food demand and agricultural activity will also increase. However, ~30–40% of the food produced today is lost or wasted along the production chain. Increasing food demands would only intensify the existing challenges associated with agri-food waste management. An innovative approach to recover the resources lost along the production chain and convert them into value-added product(s) would be beneficial. An alternative solution is the use of the larvae of the black soldier fly (BSFL), Hermetia illucens L., which can grow and convert a wide range of organic waste materials into insect biomass with use as animal feed, fertilizer and/or bioenergy. However, the main concern when creating an economically viable business is the variability in BSFL bioconversion and processing due to the variability of the substrate. Many factors, such as the nutritional composition of the substrate heavily impact BSFL development. Another concern is that substrates with high lignin and cellulose contents have demonstrated poor digestibility by BSFL. Studies suggest that pretreatment methods may improve the digestibility and biodegradability of the substrate by BSFL. However, a systematic review of existing pretreatment methods that could be used for enhancing the bioconversion of these wastes by BSFL is lacking. This paper provides a state-of-the-art review on the potential pretreatment methods that may improve the digestibility of substrates by BSFL and consequently the production of BSFL. These processes include but are not limited to, physical (e.g., mechanical and thermal), chemical (alkaline treatments), and biological (bacterial and fungal) treatments. ispartof: Frontiers in Sustainable Food Systems vol:5 pages:1-9 status: published

Purpose: The inclusion of insect protein into the food system has been proposed as a promising solution to ensure future food security and mitigate negative environmental impacts related to food production. However, the market volume for edible insects in Europe is still small; consequently, producers need a decision-support system to ensure the sustainable upscaling of the sector. The study analyzed environmental and economic impacts of insect production to identify the most eco-efficient production scenarios. Methods: A novel modular eco-efficiency assessment approach was developed to analyze the production of dried Hermetia illucens larvae. An exemplary, industrial-scale insect production system was disaggregated into a total of 29 module variants that can be combined into 4608 distinct production scenarios, which are characterized by different feeds, energy efficiencies, and processing technologies. Environmental life cycle and cost assessments were carried out for each module variant, and eco-efficiency assessment was used to jointly assess these two sustainability dimensions. Additionally, the influence of the insect feed on the production system performance and impact was investigated by employing feed-specific scaling factors. These were used to aggregate module results into production scenario results. Results and discussion: The most eco-efficient production scenarios include energy-efficient rearing facilities that rely on blanching and microwave drying for processing. The insect feed is the largest contributor to the environmental impacts and costs, but from an eco-efficiency standpoint, the choice of feed might not be crucial. Waste-type feeds (e.g., manure, fruit, and vegetable waste) have low environmental impacts and costs, but the production scenarios based on these feeds are less efficient. The low impacts of the feed are offset by higher impacts during the rearing and processing stages. Conversely, scenarios based on higher quality feeds (e.g., by-products like wheat middlings or distiller’s grains) require less resources, but the initial feed impacts and costs are higher. Moreover, of the feed types studied, only highly processed ones, such as compound chicken feed, should be avoided for insect rearing. Conclusions: The developed modular assessment approach is efficient in assessing multiple potential insect production scenarios. It can be adapted to incorporate additional variations of the production system via additional modules. Limitations include the potential for redundant module combinations and the up-front time investment needed. Finally, the results are sensitive to methodological choices: thus, these should be carefully considered and communicated during the design of the modular assessment system., The International Journal of Life Cycle Assessment, 26 (10), ISSN:0948-3349, ISSN:1614-7502