Tolerance and Excretion of the Mycotoxins Aflatoxin B₁, Zearalenone, Deoxynivalenol, and Ochratoxin A by Alphitobius diaperinus and Hermetia illucens from Contaminated Substrates

Effect of the mycotoxins enniatin B and deoxynivalenol on the wheat aphid Sitobion avenae and on the predatory lacewing Chrysoperla carnea

BACKGROUND

Fusarium species are responsible for Fusarium head blight (FHB) in wheat, resulting in yield losses and mycotoxin contamination. Deoxynivalenol (DON) and enniatins (ENNs) are common mycotoxins produced by Fusarium, affecting plant, animal and human health. Although DON's effects have been widely studied, limited research has explored the impact of ENNs on insects. This study examines the influence of DON and enniatin B (ENB), both singularly and in combination, on the wheat aphid Sitobion avenae and one of its predators, the lacewing Chrysoperla carnea.

RESULTS

When exposed to DON (100 mg L-1) or DON + ENB (100 mg L-1), S. avenae exhibited significantly increased mortality compared to the negative control. ENB (100 mg L-1) had no significant effect on aphid mortality. DON-treated aphids showed increasing mortality from 48 to 96 h. A dose-response relationship with DON revealed significant cumulative mortality starting at 25 mg L-1. By contrast, C. carnea larvae exposed to mycotoxins via cuticular application did not show significant differences in mortality when mycotoxins were dissolved in water but exhibited increased mortality with acetone-solubilized DON + ENB (100 mg L-1). Feeding C. carnea with aphids exposed to mycotoxins (indirect exposure) did not impact their survival or predatory activity. Additionally, the impact of mycotoxins on C. carnea was observed only with acetone-solubilized DON + ENB.

CONCLUSIONS

These findings shed light on the complex interactions involving mycotoxins, aphids and their predators, offering valuable insights for integrated pest management strategies. Further research should explore broader ecological consequences of mycotoxin contamination in agroecosystems. © 2024 Society of Chemical Industry.

The role of larvae of black soldier fly and house fly and of feed substrate microbes in biotransformation of aflatoxin B1

Over the past few years, there has been growing interest in the ability of insect larvae to convert various organic side-streams containing mycotoxins into insect biomass that can be used as animal feed. Various studies have examined the effects of exposure to aflatoxin B1 (AFB1) on a variety of insect species, including the larvae of the black soldier fly (BSFL; Hermetia illucens L.; Diptera: Stratiomyidae) and the housefly (HFL; Musca domestica L.; Diptera: Muscidae). Most of these studies demonstrated that AFB1 degradation takes place, either enzymatic and/or non-enzymatic. The possible role of feed substrate microorganisms (MOs) in this process has thus far not been investigated. The main objective of this study was therefore to investigate whether biotransformation of AFB1 occurred and whether it is caused by insect-enzymes and/or by microbial enzymes of MOs in the feed substrate. In order to investigate this, sterile and non-sterile feed substrates were spiked with AFB1 and incubated either with or without insect larvae (BSFL or HFL). The AFB1 concentration was determined via LC-MS/MS analyses and recorded over time. Approximately 50% of the initially present AFB1 was recovered in the treatment involving BSFL, which was comparable to the treatment without BSFL (60%). Similar patterns were observed for HFL. The molar mass balance of AFB1 for the sterile feed substrates with BSFL and HFL was 73% and 78%, respectively. We could not establish whether non-enzymatic degradation of AFB1 in the feed substrates occurred. The results showed that both BSFL and substrate-specific MOs play a role in the biotransformation of AFB1 as well as in conversion of AFB1 into aflatoxin P1 and aflatoxicol, respectively. In contrast, HFL did not seem to contribute to AFB1 degradation. The obtained results contribute to our understanding of aflatoxin metabolism by different insect species. This information is crucial for assessing the safety of feeding fly larvae with feed substrates contaminated with AFB1 with the purpose of subsequent use as animal feed.

Effects of high doses of zearalenone on some antioxidant enzymes and locomotion of Tenebrio molitor larvae (Coleoptera: Tenebrionidae)

The mealworm Tenebrio molitor L. (Coleoptera: Tenebrionidae) feeds on wheat bran and is considered both a pest and an edible insect. Its larvae contain proteins and essential amino acids, fats, and minerals, making them suitable for animal and human consumption. Zearalenone (ZEA) is the mycotoxin most commonly associated with Fusarium spp. It is found in cereals and cereal products, so their consumption is a major risk for mycotoxin contamination. One of the most important effects of ZEA is the induction of oxidative stress, which leads to physiological and behavioral changes. This study deals with the effects of high doses of ZEA (10 and 20 mg/kg) on survival, molting, growth, weight gain, activity of antioxidant enzymes superoxide dismutase (SOD) and glutathione S-transferase (GST), and locomotion of mealworm larvae. Both doses of ZEA were found to (i) have no effect on survival, (ii) increase molting frequency, SOD, and GST activity, and (iii) decrease body weight and locomotion, with more pronounced changes at 20 mg/kg. These results indicated the susceptibility of T. molitor larvae to high doses of ZEA in feed.

Effects of dietary exposure to plant toxins on bioaccumulation, survival, and growth of black soldier fly (Hermetia illucens) larvae and lesser mealworm (Alphitobius diaperinus)

In their natural habitat, insects may bioaccumulate toxins from plants for defence against predators. When insects are accidently raised on feed that is contaminated with toxins from co-harvested herbs, this may pose a health risk when used for human or animal consumption. Plant toxins of particular relevance are the pyrrolizidine alkaloids (PAs), which are genotoxic carcinogens produced by a wide variety of plant species and the tropane alkaloids (TAs) which are produced by a number of Solanaceae species. This study aimed to investigate the transfer of these plant toxins from substrates to black soldier fly larvae (BSFL) and lesser mealworm (LMW). PAs and the TAs atropine and scopolamine were added to insect substrate simulating the presence of different PA- or TA-containing herbs, and BSFL and LMW were grown on these substrates. Bioaccumulation from substrate to insects varied widely among the different plant toxins. Highest bioaccumulation was observed for the PAs europine, rinderine and echinatine. For most PAs and for atropine and scopolamine, bioaccumulation was very low. In the substrate, PA N-oxides were quickly converted to the corresponding tertiary amines. More research is needed to verify the findings of this study at larger scale, and to determine the potential role of the insect and/or substrate microbiome in metabolizing these toxins.

An alternative peptone preparation using Hermetia illucens (Black soldier fly) hydrolysis: process optimization and performance evaluation

Background

Hermetia illucens (HI), commonly known as the black soldier fly, has been recognized for its prowess in resource utilization and environmental protection because of its ability to transform organic waste into animal feed for livestock, poultry, and aquaculture. However, the potential of the black soldier fly's high protein content for more than cheap feedstock is still largely unexplored.

Methods

This study innovatively explores the potential of H. illucens larvae (HIL) protein as a peptone substitute for microbial culture media. Four commercial proteases (alkaline protease, trypsin, trypsase, and papain) were explored to hydrolyze the defatted HIL, and the experimental conditions were optimized via response surface methodology experimental design. The hydrolysate of the defatted HIL was subsequently vacuum freeze-dried and deployed as a growth medium for three bacterial strains (Staphylococcus aureus, Bacillus subtilis, and Escherichia coli) to determine the growth kinetics between the HIL peptone and commercial peptone.

Results

The optimal conditions were 1.70% w/w complex enzyme (alkaline protease: trypsin at 1:1 ratio) at pH 7.0 and 54 °C for a duration of 4 h. Under these conditions, the hydrolysis of defatted HIL yielded 19.25% ±0.49%. A growth kinetic analysis showed no significant difference in growth parameters (μmax, Xmax, and λ) between the HIL peptone and commercial peptone, demonstrating that the HIL hydrolysate could serve as an effective, low-cost alternative to commercial peptone. This study introduces an innovative approach to HIL protein resource utilization, broadening its application beyond its current use in animal feed.

A nivalenol imprinted quartz crystal microbalance sensor based on sulphur-incorporating cobalt ferrite and its application to rice samples

Nivalenol as a mycotoxin pesticide is toxic to humans and animals and causes major health problems including hemorrhage, anemia, and vomiting. Thus, the need for fast and reliable analytical systems in terms of the management of health risks resulting from nivalenol exposure has increased in recent years. The aim of this study involved a novel molecularly imprinted quartz crystal microbalance sensor preparation based on sulphur-incorporating cobalt ferrite for nivalenol detection in rice samples. For this aim, cobalt ferrite and sulfur incorporated cobalt ferrite were successfully synthesized by sol-gel and calcination methods, respectively. Then, nivalenol imprinted quartz crystal microbalance chips based on cobalt ferrite and sulfur incorporated cobalt ferrite were prepared by an ultraviolet polymerization technique including N,N'-azobisisobutyronitrile as the initiator, ethylene glycol dimethacrylate as the cross-linker, methacryloylamidoglutamic acid as the monomer, and nivalenol as the analyte. After some spectroscopic, electrochemical and microscopic characterization studies, the developed sensor was applied to rice grain samples for the determination of nivalenol. The linearity of the prepared sensor was observed to be 1.0-10.0 ng L-1 and the limit of quantification and detection limit were found to be 1.0 and 0.33 ng L-1, respectively. Finally, the high selectivity, repeatability, and stability of the prepared sensor based on sulphur-incorporating cobalt ferrite and a molecularly imprinted polymer can ensure safe food consumption worldwide.

The Potential of Edible Insects as a Safe, Palatable, and Sustainable Food Source in the European Union

Entomophagy describes the practice of eating insects. Insects are considered extremely nutritious in many countries worldwide. However, there is a lethargic uptake of this practice in Europe where consuming insects and insect-based foodstuffs is often regarded with disgust. Such perceptions and concerns are often due to a lack of exposure to and availability of food-grade insects as a food source and are often driven by neophobia and cultural norms. In recent years, due to accelerating climate change, an urgency to develop alternate safe and sustainable food-sources has emerged. There are currently over 2000 species of insects approved by the World Health Organization as safe to eat and suitable for human consumption. This review article provides an updated overview of the potential of edible insects as a safe, palatable, and sustainable food source. Furthermore, legislation, food safety issues, and the nutritional composition of invertebrates including, but not limited, to crickets (Orthoptera) and mealworms (Coleoptera) are also explored within this review. This article also discusses insect farming methods and the potential upscaling of the industry with regard to future prospects for insects as a sustainable food source. Finally, the topics addressed in this article are areas of potential concern to current and future consumers of edible insects.

An analysis of emerging food safety and fraud risks of novel insect proteins within complex supply chains

Food consumption play a crucial role in human life, yet conventional food production and consumption patterns can be detrimental to the environment. Thus, research and development has been directed towards alternative proteins, with edible insects being promising sources. Edible insects have been recognised for their sustainable benefits providing protein, with less emission of greenhouse gas, land and water usage compared to sources, such as beef, chicken, and dairy products. Among the over 2000 known edible insect species, only four, namely yellow mealworm (Tenebrio molitor), migratory locust/grasshopper (Locusta migratoria), grain mould beetle, also known as lesser mealworm which is a larval form of Alphitobius diaperinus (from the family of Tenebrionidae of darkling beetles) and house cricket (Acheta domesticus), are currently authorised in specific products through specific producers in the EU. The expansion of such foods into Western diets face challenges such as consumer barriers, gaps in microbiological and chemical safety hazard data during production and processing, and the potential for fraudulent supply chain activity. The main aim of this study was to map the supply chain, through interviews with personnel along the supply chain, coupled with searches for relevant publications and governmental documents. Thus, the main potential points of food safety and fraud along the edible insect supply chain were identified. Feed substrate was identified as the main area of concern regarding microbiological and chemical food safety and novel processing techniques were forecast to be of most concern for future fraudulent activity. Despite the on-going authorisation of insect species in many countries there are substantial food safety and authenticity information gaps in this industry that need to be addressed before edible insects can be viewed as a safe and sustainable protein sources by Western consumers.

Alternative and Sustainable Protein Sources in Pig Diet: A Review

The search for alternative protein sources to soybean meal (SBM) in animal feeding is a strategic objective to reduce production costs and contribute to sustainable animal production. Spirulina, due to the high protein content, has emerged as a potential cost-effective, sustainable, viable, and high-nutritional-value food resource for many animal species. Insect larvae (Tenebrio molitor and Hermetia illucens) are also considered potential alternatives to SBM, given their high edible percentage of almost 100%, as well as a protein value higher than that of vegetable proteins. Rapeseed meal and grain legumes, such as fava beans, peas, lupins, and chickpea, can also be used as locally producible protein ingredients. This study reviews the nutritional value of these potential alternatives to SBM in pig diets, and their effects on animal performance, digestion, immune system, and the physicochemical and sensorial characteristics of meat, including processed pork products. The limits on their use in pig feeding are also reviewed to indicate gaps to be filled in future research on the supplementation level of these potential alternative protein sources in pig diets.

Suitability of maize crop residue fermented by Pleurotus ostreatus as feed for edible crickets: growth performance, micronutrient content, and iron bioavailability

Small-scale farming of edible insects could help combat public health challenges such as protein energy malnutrition and anemia, but reliable low-cost feeds for insects are needed. In resource-limited contexts, where grains such as maize are prohibitively costly for use as insect feed, the feasibility of insect farming may depend on finding alternatives. Here, we explore the potential to modify plentiful maize crop residue with edible mushroom mycelium to generate a low-cost feed adjunct for the farmed two-spotted cricket, Gryllus bimaculatus. Mushroom farming, like insect agriculture, is versatile; it can yield nutritious food while increasing system circularity by utilizing lignocellulosic residues from row crops as inputs. Pleurotus ostreatus, is an edible basidiomycete capable of being cultivated on corn stover (Zea mays). Mushroom harvest results in abundant "spent" substrate, which we investigated as a candidate feed ingredient. We created six cricket feeds containing fermented Pleurotus substrate plus an unfermented control, measuring cricket mass, mortality, and maturation weekly to evaluate cricket growth performance impacts of both fungal fermentation duration and mushroom formation. Pasteurized corn stover was inoculated with P. ostreatus mycelium and fermented for 0, 2, 3, 4, or 8 weeks. Some 4 and 8-week substrates were induced to produce mushrooms through manipulations of temperature, humidity, and light conditions. Dried fermented stover (40%) was added to a 1:1 corn/soy grain mix and fed to crickets ad libitum for 44 days. The unfermented control group showed higher survivorship compared to several fermented diets. Control group mass yield was higher for 2 out of 6 fermented diets. Little variation in cricket iron content was observed via ICP-spectrometry across feeds, averaging 2.46 mg/100 g. To determine bioavailability, we conducted in vitro Caco-2 human colon epithelial cell absorption assays, showing that iron in crickets fed fruiting-induced substrates was more bioavailable than in unfruited groups. Despite more bioavailable iron in crickets reared on post-fruiting substrates, we conclude that Pleurotus-fermented stover is an unsuitable feed ingredient for G. bimaculatus due to high mortality, variability in growth responses within treatments, and low mass yield.

Effects of undesired substances and their bioaccumulation on the black soldier fly larvae, Hermetia illucens (Diptera: Stratiomyidae)-a literature review

Black soldier fly (BSF), Hermetia illucens (L.) (Diptera: Stratiomyidae), is predominantly reared on organic wastes and other unused complementary substrates. However, BSF may have a buildup of undesired substances in their body. The contamination of undesired substance, e.g., heavy metals, mycotoxins, and pesticides, in BSF mainly occurred during the feeding process in the larval stage. Yet, the pattern of accumulated contaminants in the bodies of BSF larvae (BSFL) is varied distinctively depending on the diets as well as the contaminant types and concentrations. Heavy metals, including cadmium, copper, arsenic, and lead, were reported to have accumulated in BSFL. In most cases, the cadmium, arsenic, and lead concentration in BSFL exceeded the recommended standard for heavy metals occurring in feed and food. Following the results concerning the accumulation of the undesired substance in BSFL's body, they did not affect the biological parameters of BSFL, unless the amounts of heavy metals in their diets are highly exceeding their thresholds. Meanwhile, a study on the fate of pesticides and mycotoxins in BSFL indicates that no bioaccumulation was detected for any of the target substances. In addition, dioxins, PCBs, PAHs, and pharmaceuticals did not accumulate in BSFL in the few existing studies. However, future studies are needed to assess the long-term effects of the aforementioned undesired substances on the demographic traits of BSF and to develop appropriate waste management technology. Since the end products of BSFL that are contaminated pose a threat to both human and animal health, their nutrition and production process must be well managed to create end products with a low contamination level to achieve a closed food cycle of BSF as animal feed.

Mycotoxins on edible insects: Should we be worried?

Edible insects are a solid alternative to meet the growing demand for animal protein. However, there are doubts regarding the safety of insect consumption. Mycotoxins are substances of concern for food safety, as they may cause harmful effects on the human organism and accumulate in the tissues of some animals. This study focuses on the characteristics of the main mycotoxins, the mitigation of human consumption of contaminated insects, and the effects of mycotoxins on insect metabolism. To date, studies reported the interaction of the mycotoxins aflatoxin B1, ochratoxin A, zearalenone, deoxynivalenol, fumonisin B1, and T-2, isolated or combined, in three insect species from Coleoptera and one from Diptera order. The use of rearing substrates with low mycotoxin contamination did not reduce the survival and development of insects. Fasting practices and replacing contaminated substrate with a decontaminated one decreased the concentration of mycotoxins in insects. There is no evidence that mycotoxins accumulate in the tissues of the insects' larvae. Coleoptera species showed high excretion capacity, while Hermetia illucens had a lower excretion capacity of ochratoxin A, zearalenone, and deoxynivalenol. Thus, a substrate with low mycotoxin contamination could be used for raising edible insects, particularly from the Coleoptera order.

Impact of Enniatin and Deoxynivalenol Co-Occurrence on Plant, Microbial, Insect, Animal and Human Systems: Current Knowledge and Future Perspectives

Fusarium mycotoxins commonly contaminate agricultural products resulting in a serious threat to both animal and human health. The co-occurrence of different mycotoxins in the same cereal field is very common, so the risks as well as the functional and ecological effects of mycotoxins cannot always be predicted by focusing only on the effect of the single contaminants. Enniatins (ENNs) are among the most frequently detected emerging mycotoxins, while deoxynivalenol (DON) is probably the most common contaminant of cereal grains worldwide. The purpose of this review is to provide an overview of the simultaneous exposure to these mycotoxins, with emphasis on the combined effects in multiple organisms. Our literature analysis shows that just a few studies on ENN-DON toxicity are available, suggesting the complexity of mycotoxin interactions, which include synergistic, antagonistic, and additive effects. Both ENNs and DON modulate drug efflux transporters, therefore this specific ability deserves to be explored to better understand their complex biological role. Additionally, future studies should investigate the interaction mechanisms of mycotoxin co-occurrence on different model organisms, using concentrations closer to real exposures.

Chronic exposure to zearalenone induces intestinal inflammation and oxidative injury in adult Drosophila melanogaster midgut

In the past decade, mycotoxin zearalenone (ZEN)-induced gastrointestinal adverse effects have been increasingly attracting worldwide attention. This study aimed to determine the gastrointestinal adverse effects of ZEN in Drosophila melanogaster (D. melanogaster) and reveal possible mechanisms of action of ZEN in insects. Here, chronic exposure of D. melanogaster to ZEN killed flies in a dose-dependent manner (2-20 µM). ZEN (20 µM) decreased the survival rates and climbing ability of flies, and activated immune deficiency-mediated intestinal immunity in midgut, leading to the production of antimicrobial peptides. Meanwhile, ZEN exposure induced morphological alteration of adult midgut. Further study suggested that high levels of oxidative stress was observed in ZEN-treated midgut due to the imbalance between the production of reactive oxygen species and the expression and activities of cellular antioxidant enzyme, including superoxide dismutase and catalase. ZEN-induced oxidative stress then caused cell death, impaired gut barrier function and increased gut permeability, leading to oxidative injury in midgut. Subsequently, ZEN-induce midgut injury further disrupted intestinal stem cell (ISC) homeostasis, stimulating ISC proliferation and tissue regeneration, but did not alter cell fate specification of ISC. Additionally, activation of Jun N-terminal kinase pathway was involved in ZEN-induced oxidative injury and tissue regeneration in midgut. Antioxidant vitamin E alleviated ZEN-induced oxidative injury to midgut epithelium. Collectively, this study provided additional evidences for ZEN-induced gastrointestinal adverse effects from an invertebrate model, extended our understanding of the mechanisms mediating mycotoxin toxicity in organisms.

Characteristics of Aflatoxin B1 Degradation by Stenotrophomonas acidaminiphila and It's Combination with Black Soldier Fly Larvae

Aflatoxin B₁ (AFB₁) is a common mycotoxin contaminant in cereals that causes severe economic losses and serious risks to the health of humans and animals. In this paper, we investigated the characteristics of AFB₁ degradation by black soldier fly larvae (BSFL) combined with commensal intestinal microorganisms. Germ-free BSFL and non-sterile BSFL were reared on peanut meal spiked with AFB₁ for 10 days. The result showed that germ-free BSFL and non-sterile BSFL could achieve 31.71% and 88.72% AFB₁ degradation, respectively, which indicated the important role of larvae gut microbiota in AFB₁ degradation. Furthermore, twenty-five AFB₁-degrading bacteria were isolated from BSFL gut, and S. acidaminiphila A2 achieved the highest AFB₁ degradation, by 94%. When S. acidaminiphila A2 was re-inoculated to BSFL, the detrimental effect of AFB₁ on the growth performance of BSFL was alleviated, and complete AFB₁ degradation in peanut meal was obtained. In conclusion, the present study may provide a strategy to degrade AFB₁ in feedstuff through bioconversion with BSFL in combination with gut-originated AFB₁-degrading bacteria, while providing a sustainable insect protein and fat source to animals.

Modified Mycotoxins, a Still Unresolved Issue

Mycotoxins are toxic secondary metabolites produced by filamentous microfungi on almost every agricultural commodity worldwide. After the infection of crop plants, mycotoxins are modified by plant enzymes or other fungi and often conjugated to more polar substances, like sugars. The formed—often less toxic—metabolites are stored in the vacuole in soluble form or bound to macromolecules. As these substances are usually not detected during routine analysis and no maximum limits are in force, they are called modified mycotoxins. While, in most cases, modified mycotoxins have lower intrinsic toxicity, they might be reactivated during mammalian metabolism. In particular, the polar group might be cleaved off (e.g., by intestinal bacteria), releasing the native mycotoxin. This review aims to provide an overview of the critical issues related to modified mycotoxins. The main conclusion is that analytical aspects, toxicological evaluation, and exposure assessment merit more investigation.

The enhanced degradation behavior of oxytetracycline by black soldier fly larvae with tetracycline resistance genes in the larval gut: Kinetic process and mechanism

Black soldier fly larvae (larvae) can digest organic wastes and degrade contaminants such as oxytetracycline (OTC). However, compared to the kinetic processes and enhanced mechanisms used in the traditional microbial degradation of OTC, those employed by larvae are largely uncharacterized. To obtain further details, a combined analysis of larval development, larval nutritional values (crude protein, crude fat and the composition of fatty acids) and the expression of tetracycline resistance genes (TRGs) in the larval gut was performed for the degradation of OTC added to substrates and for oxytetracycline bacterial residue (OBR). When the larvae were exposed to the substrates, the degradation processes were enhanced significantly (P < 0.01), with a 4.74-7.86-fold decrease in the degradation half-life (day^-1) and a 3.34-5.74-fold increase in the final degradation efficiencies. This result was attributed to the abundant TRGs (with a detection rate of 35.90%∼52.14%) in the larval gut. The TRGs presented the resistance mechanisms of cellular protection and efflux pumps, which ensured that the larvae could tolerate elevated OTC concentrations. Investigation of the TRGs indicated that enzymatic inactivation enhanced OTC degradation by larvae. These findings demonstrate that the larval degradation of antibiotic contaminants is an efficient method based on abundant TRGs in the larval gut, even though OTC degradation results in OBR. In addition, a more optimized system for higher reductions in antibiotic levels and the expansion of larval bioremediation to other fields is necessary.

Detoxication and bioconversion of aflatoxin B1 by yellow mealworms (Tenebrio molitor): A sustainable approach for valuable larval protein production from contaminated grain

Yellow mealworm (Tenebrio molitor) is a supplementary protein source for food and feed and represents a promising solution to manage grain contaminated with Aflatoxin B₁ (AFB₁). In this study, AFB₁ present in different concentrations in wheat bran was treated and removed via bioconversion by yellow mealworm of different instars, with emphasis on the bioconversion performance and metabolism of AFB₁. Upon application of wheat bran spiked with 100 μg/kg AFB₁ to 5th-6th instar yellow mealworms, the conversion rate of AFB₁ was up to 87.85 %. Low level of AFB₁ (< 2 μg/kg) was accumulated in the larval bodies, and the survival rate, development and nutrition contents of yellow mealworm were not significantly affected. It was revealed that 1 kg of wheat bran contaminated with AFB₁ increased the weight of yellow mealworms from 138 g to 469 g, containing approximately 103 g of protein. The bioconversion of AFB₁ by yellow mealworms led to generation of 13 metabolites in the frass and 3 metabolites in the larvae. AFB₁ was detoxicated and removed via phase I metabolism comprising reduction, dehydrogenation, hydration, demethylation, hydroxylation, decarbonylation and ketoreduction, followed by phase II metabolism involving conjugation of amino acid, glucoside and glutathione (GSH). The toxicity of AFB₁ metabolites was deemed lower than that of AFB₁ according to their structures. This study provides a sustainable approach and theoretical foundation on using yellow mealworms for cleaner grain contamination management and valuable larval protein production via bioconversion of food and feed contaminated by AFB₁.

Insects as Feed for Companion and Exotic Pets: A Current Trend

Simple Summary

Currently, there is a wide variety of insect-based pet foods and treats; however, there are several questions about the nutritional contribution of insects for dogs and cats, their health effects, safety aspects and the legal framework for their use as ingredients or feed. The insect-based ingredients used are mainly meal and fat from black soldier fly larvae, mealworm larvae and adult house crickets. There are few studies on the use of insects as food ingredients for pets, and most of them have studied some aspects in dogs. It has been said that they do not affect health, are well accepted and tolerated, do not alter the microbiota and could have the potential to be used as hypoallergenic ingredients. Insects provide a high nutritional value, with a high content of protein and amino acids with good digestibility for dogs. In cats, there is scarce information and more studies are needed. In exotic pets, their use is generalized. Dog owners are willing to use insects as ingredients, but in processed formats such as meal or as part of food or treats. Future research should focus on safety issues and effects on the health, nutrition and feeding behavior of traditional pets, such as dogs and cats.

Abstract

The objective of this review was to carry out a comprehensive investigation of the benefits of incorporating insects as a pet food ingredient and the implications this can have in determining a market demand for insect-based pet foods. Black soldier fly larvae (Hermetia illucens), mealworm larvae (Tenebrio molitor) and adult house crickets (Acheta domesticus) are currently used in pet food. These insects are widely fed to exotic pets, mainly in whole, live or dehydrated formats. They are also incorporated as meal or fat and are offered to cats and dogs as dry or wet food and treats. Scientific studies about the use of insects for dog and cat feed are scarce. Most studies are in dogs. Research shows that insect nutrients, mainly amino acids, have high digestibility, are beneficial to health, do not have any detrimental effect on the gut microbiota and are accepted by dogs. In several countries, insects are approved for use in pet food and commercialization has spread throughout the world. Pet owners are willing to try foods made with insect meal for their pets. In conclusion, the use of insects in pet food is a reality that is taking on more and more prominence.

Microfluidics-Based Time-Resolved Fluorescence Immunoassay for the On-Site Detection of Aflatoxins B1 Zearalenone and Deoxynivalenol in Cereals

The primary pollutants in cereal products are aflatoxins B1 (AFB1), zearalenone (ZEN), and deoxynivalenol (DON). In this study, anti-AFB1 MAb (4C9), anti-ZEN MAb (2A3), and anti-DON MAb (1F10) were developed and used in time-resolved fluorescence immunoassay microfluidics to determine AFB1, ZEN, and DON in agricultural products. The linear range for AFB1, ZEN, and DON were 0.05~2.2 μg/kg, 1.45~375.75 μg/kg, and 11.1~124.2 μg/kg, respectively. In maize, the recoveries of AFB1/ZEN/DON were 92~101%, 102~105%, and 103~108%, respectively. High-performance liquid chromatography and the proposed approach had a good correlation. Time-resolved fluorescence immunoassay microfluidics is a highly efficient and sensitive field detection method for fungal toxins in agricultural products.

Aflatoxin B1 Metabolism of Reared Alphitobius diaperinus in Different Life-Stages

The presence of carcinogenic aflatoxins in food and feed is a major issue. In prior studies, aflatoxin B1 (AfB1) and known primary metabolites were absent from Lesser Mealworm (LMW, Alphitobius diaperinus) reared on contaminated diets. LMW is a promising alternative protein source. The objectives of this stu\dy were to determine whether LMW can be reared on AfB1-contaminated feed in each life-stage, and to gather more insight into potential metabolites formed. Results suggested no adverse effects in terms of survival/growth when three stages of LMW (larvae, pre-pupae, beetles) were exposed to feed containing AfB1 concentrations of 200 and 600 µg/kg for 48 h. Insect and frass samples were analyzed by LC-MS/MS and high-resolution MS to, respectively, quantify concentrations of AfB1 and its major metabolites, and determine secondary metabolites. No AfB1 or major metabolites were quantified in the insect samples. Mass balance calculations showed that up to 40% of spiked AfB1 could be recovered in the frass, in the form of AfB1, aflatoxicol and AfM1. HRMS results suggested the presence of additional metabolites in the frass, but, due to lack of commercially available reference standards for these compounds, exact identification and quantification was not possible. More research is needed to verify the absence of toxicity.

Mycotoxin Metabolism by Edible Insects

Mycotoxins are a group of toxic secondary metabolites produced in the food chain by fungi through the infection of crops both before and after harvest. Mycotoxins are one of the most important food safety concerns due to their severe poisonous and carcinogenic effects on humans and animals upon ingestion. In the last decade, insects have received wide attention as a highly nutritious, efficient and sustainable source of animal-derived protein and caloric energy for feed and food purposes. Many insects have been used to convert food waste into animal feed. As food waste might contain mycotoxins, research has been conducted on the metabolism and detoxification of mycotoxins by edible insects. The mycotoxins that have been studied include aflatoxins, fumonisins, zearalenone (ZEN), vomitoxin or deoxynivalenol (DON), and ochratoxins (OTAs). Aflatoxin metabolism is proved through the production of hydroxylated metabolites by NADPH-dependent reductases and hydroxylases by different insects. ZEN can be metabolized into α- and β-zearalenol. Three DON metabolites, 3-, 15-acetyl-DON, and DON-3-glucoside, have been identified in the insect DON metabolites. Unfortunately, the resulting metabolites, involved enzymes, and detoxification mechanisms of OTAs and fumonisins within insects have yet to be identified. Previous studies have been focused on the insect tolerance to mycotoxins and the produced metabolites; further research needs to be conducted to understand the exact enzymes and pathways that are involved.

Overcoming Technical and Market Barriers to Enable Sustainable Large-Scale Production and Consumption of Insect Proteins in Europe: A SUSINCHAIN Perspective

Simple Summary

Insects are increasingly being used in Europe as a new or alternative source of protein for both direct human consumption and ingredients for feed and food production. Upscaling edible insect production and processing to a sustainable industrial sector is critical to supply the market and meet the foreseen future demands. In a market where transition to more sustainable protein sources is one of the primary challenges, sustainable insect products can contribute to a circular and sustainable economy as well as food security. SUSINCHAIN (SUStainable INsect CHAIN) is a European Horizon 2020 project that aims to contribute to overcome technical and market barriers to enable sustainable large-scale production and consumption of insect proteins in Europe by generating and sharing knowledge, as well as testing, piloting, and demonstrating newly developed insect chain innovations and increasing societal engagement. This article provides an outline of the various obstacles to upscaling of the insect sector and the project’s contributions to overcome these. The project covers the topics of: market opportunities, consumer perception, optimization of insect rearing conditions and substrates, insect transportation and processing techniques, application of insect products in food and feed, food safety issues in insect production and processing, together with economic and environmental sustainability. The project’s outcomes will provide tools for scaling up and commercializing the European insect sector.

Abstract

The expected global population growth to 9.7 billion people in 2050 and the significant change in global dietary patterns require an increase in global food production by about 60%. The protein supply for feed and food is most critical and requires an extension in protein sources. Edible insects can upgrade low-grade side streams of food production into high-quality protein, amino acids and vitamins in a very efficient way. Insects are considered to be the “missing link” in the food chain of a circular and sustainable economy. Insects and insect-derived products have entered the European market since first being acknowledged as a valuable protein source for feed and food production in around 2010. However, today, scaling up the insect value chain in Europe is progressing at a relatively slow pace. The mission of SUSINCHAIN (SUStainable INsect CHAIN)—a four-year project which has received funding from the European Commission—is to contribute to novel protein provision for feed and food in Europe by overcoming the remaining barriers for increasing the economic viability of the insect value chain and opening markets by combining forces in a comprehensive multi-actor consortium. The overall project objective is to test, pilot and demonstrate recently developed technologies, products and processes, to realize a shift up to Technology Readiness Level 6 or higher. In addition to these crucial activities, the project engages with stakeholders in the insect protein supply chain for feed and food by living labs and workshops. These actions provide the necessary knowledge and data for actors in the insect value chain to decrease the cost price of insect products, process insects more efficiently and market insect protein applications in animal feed and regular human diets that are safe and sustainable. This paves the way for further upscaling and commercialization of the European insect sector.

Staphylococcus aureus in Substrates for Black Soldier Fly Larvae (Hermetia illucens) and Its Dynamics during Rearing

Black soldier fly larvae (BSFL; Hermetia illucens) are promising insects for the conversion of organic waste streams into valuable biomolecules. Such waste streams can contain foodborne pathogens. To assess this risk factor, this study evaluated the presence of Staphylococcus aureus in waste streams as a substrate ingredient for BSFL production as well as in the rearing process. First, the general microbiological quality and the occurrence of S. aureus were investigated for different waste streams. Staphylococcus aureus was abundantly present. Control of pH and water activity should avoid pathogens, which cannot grow in single-substrate ingredients, redeveloping when mixing streams for optimal substrate conditions for BSFL production. Next, it was investigated whether S. aureus present in the substrate was ingested and/or eradicated by BSFL. In inoculation trials, with S. aureus added to chicken feed as the substrate at 3 or 7 log CFU/g, the larvae showed a reducing effect on S. aureus. After 6 days, S. aureus counts were below the detection limit (2.0 log CFU/g) in all larvae samples and decreased in the substrate to <2.0 and <3.1 log CFU/g for inoculation levels of 3 and 7 log CFU/g, respectively. While this is promising, it is still recommended to monitor and control this pathogen in BSFL rearing. Intriguingly, screening of antimicrobial activity of dominant microorganisms associated with BSFL showed a clear activity of Trichosporon isolates against S. aureus. Future research should explore whether Trichosporon, which is frequently observed in BSFL, plays a role in controlling specific microorganisms, such as S. aureus. IMPORTANCE Given the increasing need for (more sustainable) methods to upcycle organic waste streams, the interest to rear insects, like black soldier fly larvae (BSFL), on such streams is increasing. This study reveals that S. aureus is abundantly present in such waste streams, which might be a point of attention for insect producers. At the same time, it reveals that when S. aureus was inoculated in chicken feed as the substrate, it was not detected in the larvae and was reduced in the substrate after 6 days. Future inoculation trials should investigate whether this reduction is substrate dependent or not. Toward the future, the role of the BSFL microbiota in controlling intestinal bacterial community homeostasis should be explored, because one of the dominant microorganisms associated with BSFL, Trichosporon spp., showed clear activity against S. aureus.

Yellow Mealworm and Black Soldier Fly Larvae for Feed and Food Production in Europe, with Emphasis on Iceland

Insects are part of the diet of over 2 billion people worldwide; however, insects have not been popular in Europe, neither as food nor as a feed ingredient. This has been changing in recent years, due to increased knowledge regarding the nutritional benefits, the need for novel protein production and the low environmental impact of insects compared to conventional protein production. The purpose of this study is to give an overview of the most popular insects farmed in Europe, yellow mealworm, Tenebrio molitor, and black soldier fly (BSF), Hermetia illucens, together with the main obstacles and risks. A comprehensive literature study was carried out and 27 insect farming companies found listed in Europe were contacted directly. The results show that the insect farming industry is increasing in Europe, and the success of the frontrunners is based on large investments in technology, automation and economy of scale. The interest of venture capital firms is noticeable, covering 90% of the investment costs in some cases. It is concluded that insect farming in Europe is likely to expand rapidly in the coming years, offering new proteins and other valuable products, not only as a feed ingredient, but also for human consumption. European regulations have additionally been rapidly changing, with more freedom towards insects as food and feed. There is an increased knowledge regarding safety concerns of edible insects, and the results indicate that edible insects pose a smaller risk for zoonotic diseases than livestock. However, knowledge regarding risk posed by edible insects is still lacking, but food and feed safety is essential to put products on the European market.

A systematic literature review on the effects of mycotoxin exposure on insects and on mycotoxin accumulation and biotransformation

Novel protein sources for animal feed are needed, and the use of insects as feed ingredient is explored. The insect production sector offers opportunities for a circular and sustainable approach to feed production by upgrading waste or side streams into high-quality proteins. However, potential food or feed safety issues should be studied in advance. Mycotoxins, such as aflatoxin B1, are natural contaminants commonly found in agricultural crops and have proven to be detrimental to the agricultural industry, livestock, and human health. This systematic review aims to provide a comprehensive overview of the published evidence on effects of mycotoxin exposure on insect growth and survival, mycotoxin accumulation within the insect body, and metabolization of various mycotoxins by insects. The review includes 54 scientific articles published in the past 55 years, in total covering 32 insect species. The main findings are the following: (1) Insects of the order Coleoptera show lower mortality after exposure to aflatoxin B1 when compared to Lepidoptera and Diptera; (2) effects of mycotoxins on larval growth and survival are less detrimental in later larval stages; (3) accumulation of mycotoxins was low in most insect species; (4) mycotoxins are metabolized within the insect body, the degree of which depends on the particular mycotoxin and insect species; (5) cytochrome P450s are the main family of enzymes involved in biotransformation of mycotoxins in some insect species. Results of this review support an optimistic outlook for the use of mycotoxin-contaminated waste streams as substrate for insect rearing.

The use of alternative food sources to improve health and guarantee access and food intake

To feed and provide Food Security to all people in the world is a big challenge to be achieved with the 2030 Agenda. Undernutrition and obesity are to the opposite of a healthy nutritional status. Both conditions are associated with unbalanced nutrition, absence of food or excess of non-nutritive foods intake. These two nutritional conditions associated with food production are closely related to some goals highlighted by the United Nations in the 2030 Agenda to achieve sustainable world development. In this context, the search for alternative foods whose sustainable production and high nutritional quality guarantee regular access to food for the population must be encouraged. Alternative foods can contribute to Food Security in many ways as they contribute to the local economy and income generation. Popularizing and demystifying the uses of unconventional food plants, ancestral grains, flowers, meliponiculture products, and edible insects as sources of nutrients and non-nutrients is another challenge. Herein, we present an overview of alternative foods - some of them cultivated mostly in Brazil - that can be explored as sources of nutrients to fight hunger and malnutrition, improve food production and the economic growth of nations.

Metabolic fate and toxicity reduction of aflatoxin B1 after uptake by edible Tenebrio molitor larvae

The use of insects as food and feed is gaining more attention for ecological and ethical reasons. Despite the high tolerance of edible yellow mealworm (Tenebrio molitor) larvae to aflatoxin B1 (AFB1), the metabolic fate of the toxin along with its toxic potential in the insect is uncertain. The present study aimed at investigating the AFB1 mass balance and the metabolite formation in a feeding trial with AFB1-contaminated grain flour. T. molitor larvae tolerated the AFB1 level of 10,700 μg/kg in the feed, however, weight gain was decreased by 15% over a 4-weeks feeding period. The investigation of the phase I metabolite pattern revealed the formation of AFM1 and a novel presumably monohydroxylated compound in larvae extracts that was not formed by reference incubation with rat, bovine or porcine liver microsomes. Mass balance quantification of ingested AFB1 revealed that 87% of the initial toxin remain undetected in larval body or residue. Analysis of histone H2Ax phosphorylation in human liver cells as a surrogate for genotoxicity showed that extracts from exposed larvae did not exhibit an elevated toxic potential. Although toxicological uncertainties remain due to the undetected transformation products, the resulting mutagenicity of the edible larvae appears to be low.

The Chemical Ecology Approach to Reveal Fungal Metabolites for Arthropod Pest Management

Biorational insecticides (for instance, avermectins, spinosins, azadirachtin, and afidopyropen) of natural origin are increasingly being used in agriculture. The review considers the chemical ecology approach for the search for new compounds with insecticidal properties (entomotoxic, antifeedant, and hormonal) produced by fungi of various ecological groups (entomopathogens, soil saprotrophs, endophytes, phytopathogens, and mushrooms). The literature survey revealed that insecticidal metabolites of entomopathogenic fungi have not been sufficiently studied, and most of the well-characterized compounds show moderate insecticidal activity. The greatest number of substances with insecticidal properties was found to be produced by soil fungi, mainly from the genera Aspergillus and Penicillium. Metabolites with insecticidal and antifeedant properties were also found in endophytic and phytopathogenic fungi. It was noted that insect pests of stored products are mostly low sensitive to mycotoxins. Mushrooms were found to be promising producers of antifeedant compounds as well as insecticidal proteins. The expansion of the number of substances with insecticidal properties detected in prospective fungal species is possible by mining fungal genomes for secondary metabolite gene clusters and secreted proteins with their subsequent activation by various methods. The efficacy of these studies can be increased with high-throughput techniques of extraction of fungal metabolites and their analysis by various methods of chromatography and mass spectrometry.

Black Soldier Fly Larvae Can Effectively Degrade Oxytetracycline Bacterial Residue by Means of the Gut Bacterial Community

Antibiotic bacterial residue is a unique hazardous waste, and its safe and effective disposal has always been a concern of pharmaceutical enterprises. This report presents the effective treatment of hazardous waste-antibiotic bacterial residue-by black soldier fly larvae (larvae), oxytetracycline bacterial residue (OBR), and soya meal with mass ratios of 0:1 (soya), 1:20 (OBRlow), and 1:2 (OBRhigh), which were used as substrates for larval bioconversion. Degradation of OBR and oxytetracycline, the bacterial community, the incidence of antibiotic resistance genes (ARGs) and the bacterial function in the gut were examined. When the larvae were harvested, 70.8, 59.3, and 54.5% of the substrates had been consumed for soya, OBRlow and OBRhigh; 65.9 and 63.3% of the oxytetracycline was degraded effectively in OBRlow and OBRhigh, respectively. The larval bacterial communities were affected by OBR, abundant and various ARGs were discovered in the gut, and metabolism was the major predicted function of the gut. These findings show that OBR can be digested and converted by larvae with gut bacteria, and the larvae can be used as a bioremediation tool for the treatment of hazardous waste. Finally, the abundant ARGs in the gut deserve further attention and consideration in environmental health risk assessments.

Safety of Alternative Proteins: Technological, Environmental and Regulatory Aspects of Cultured Meat, Plant-Based Meat, Insect Protein and Single-Cell Protein

Food security and environmental issues have become global crises that need transformative solutions. As livestock production is becoming less sustainable, alternative sources of proteins are urgently required. These include cultured meat, plant-based meat, insect protein and single-cell protein. Here, we describe the food safety aspects of these novel protein sources, in terms of their technological backgrounds, environmental impacts and the necessary regulatory framework for future mass-scale production. Briefly, cultured meat grown in fetal bovine serum-based media can be exposed to viruses or infectious prion, in addition to other safety risks associated with the use of genetic engineering. Plant-based meat may contain allergens, anti-nutrients and thermally induced carcinogens. Microbiological risks and allergens are the primary concerns associated with insect protein. Single-cell protein sources are divided into microalgae, fungi and bacteria, all of which have specific food safety risks that include toxins, allergens and high ribonucleic acid (RNA) contents. The environmental impacts of these alternative proteins can mainly be attributed to the production of growth substrates or during cultivation. Legislations related to novel food or genetic modification are the relevant regulatory framework to ensure the safety of alternative proteins. Lastly, additional studies on the food safety aspects of alternative proteins are urgently needed for providing relevant food governing authorities with sufficient data to oversee that the technological progress in this area is balanced with robust safety standards.

Immunoassays for rapid mycotoxin detection: state of the art

The widespread presence of mycotoxins in nature not only poses a huge health risk to people in terms of food but also causes incalculable losses to the agricultural economy. As a rapidly developing technology in recent years, the mycotoxin immunoassay technology has approached or even surpassed the traditional chromatography technology in some aspects. Using this approach, the lateral flow immunoassay (LFIA) has attracted the interest of researchers due to its user-friendly operation, short time consumption, little interference, low cost, and ability to process a large number of samples at the same time. This paper provides an overview of the immunogens commonly used for mycotoxins, the development of antibodies, and the use of gold nanoparticles, quantum dots, carbon nanoparticles, enzymes, and fluorescent microsphere labeling materials for the construction of LFIAs to improve detection sensitivity. The analytical performance, detection substrates, detection limits or detection ranges of LFIA for mycotoxins have been listed in recent years. Finally, we describe the future outlook for the field, predicting that portable mobile detection devices and simultaneous quantitative detection of multiple mycotoxins is one of the important directions for future development.

Effects of insecticides on mortality, growth and bioaccumulation in black soldier fly (Hermetia illucens) larvae

Residues of persistent insecticides may be present in the substrates on which insects are reared for food and feed, which may affect insect growth or survival. In addition, insecticidal substances may bio-accumulate in reared insects. The objective of this study was to assess potential effects of selected insecticides on the growth and survival of black soldier fly larvae (BSFL, Hermetia illucens) and on their safety when used as animal feed. Six insecticides (chlorpyrifos, propoxur, cypermethrin, imidacloprid, spinosad, tebufenozide) with different modes of action were tested in two sequential experiments. Cypermethrin was also tested with the synergist piperonyl butoxide (PBO). Standard BSFL substrate was spiked to the respective maximum residue level (MRL) of each insecticide allowed by the European Union to occur in feed; and BSFL were reared on these substrates. Depending on the observed effects in the first experiment, spiked concentrations tested in the second experiment were increased or reduced. At the concentrations applied (1 and 10 times MRL), three of the six tested substances (chlorpyrifos, propoxur, tebufenozide) did not affect the survival or biomass growth of BSFL, compared to the control (non-spiked) treatments. At MRL, imidacloprid stimulated the growth of BSFL compared to the controls. Spinosad and cypermethrin at the MRL level negatively affected growth and survival. The effects of cypermethrin appeared to be augmented by addition of PBO. A mean bio-accumulation factor of ≤0.01 was found in both experiments for all substances-except for cypermethrin, which was comparatively high, but still below 1 (0.79 at 0.1 mg/kg). The lack of accumulation of insecticides in the larvae suggests that there is no risk of larval products being uncompliant with feed MRLs. However, we conclude that insecticides present in substrates may affect growth and survival of BSFL. More research on a larger variety of substances and insect species is recommended.

Mealworm (Tenebrio molitor Larvae) as an Alternative Protein Source for Monogastric Animal: A Review

Simple Summary

Tenebrio molitor (T. molitor) larvae, known as mealworm, have been considered a good protein source for monogastric animals. They have a high quantity and quality of protein content and amino acid profile. The inclusion of T. molitor larvae in broiler diets improved the growth performance without having negative effects on carcass traits and blood profiles in broiler chickens, or had no influence on the growth performance and carcass yield of broiler chickens. The supplementation of T. molitor larvae improved the growth performance and protein utilization of weaning pigs. Furthermore, the replacement of fishmeal with T. molitor larvae resulted in no difference in the growth performance and nutrient digestibility of weaning pigs. However, there are some challenges regarding biosafety, consumer’s acceptance, and price for the use of T. moiltor larvae in animal feed. Consequently, T. molitor larvae could be used as an alternative or sustainable protein source in monogastric animal feed.

Abstract

Edible insects have been used as an alternative protein source for food and animal feed, and the market size for edible insects has increased. Tenebrio molitor larvae, also known as mealworm and yellow mealworm, are considered a good protein source with nutritional value, digestibility, flavor, and a functional ability. Additionally, they are easy to breed and feed for having a stable protein content, regardless of their diets. Therefore, T. molitor larvae have been produced industrially as feed for pets, zoo animals, and even for production animals. To maintain the nutrient composition and safety of T. molitor larvae, slaughtering (heating or freezing) and post-slaughtering (drying and grinding) procedures should be improved for animal feed. T. molitor larvae are also processed with defatting or hydrolysis before grinding. They have a high quality and quantity of protein and amino acid profile, so are considered a highly sustainable protein source for replacing soybean meal or fishmeal. T. molitor has a chitin in its cuticle, which is an indigestible fiber with positive effects on the immune system. In studies of poultry, the supplementation of T. molitor larvae improved the growth performance of broiler chickens, without having negative effects on carcass traits, whereas some studies have reported that there were no significant differences in the growth performance and carcass yield of broiler chickens. In studies of swine, the supplementation of T. molitor larvae improved the growth performance and protein utilization of weaning pigs. Furthermore, 10% of T. molitor larvae showed greater amino acid digestibility than conventional animal proteins in growing pigs. However, there are some challenges regarding the biosafety, consumer’s acceptance, and price for the use of T. moiltor larvae in animal feed. Consequently, T. molitor larvae could be used as an alternative or sustainable protein source in monogastric animal feed with a consideration of the nutritional values, biosafety, consumer’s acceptance, and market price of T. molitor larvae products.

Rethinking organic wastes bioconversion: Evaluating the potential of the black soldier fly (Hermetia illucens (L.)) (Diptera: Stratiomyidae) (BSF)

Population growth and unprecedented economic growth and urbanization, especially in low- and middle-income countries, coupled with extreme weather patterns, the high-environmental footprint of agricultural practices, and disposal-oriented waste management practices, require significant changes in the ways we produce food, feed and fuel, and manage enormous amounts of organic wastes. Farming insects such as the black soldier fly (BSF) (Hermetia illucens) on diverse organic wastes provides an opportunity for producing nutrient-rich animal feed, fuel, organic fertilizer, and biobased products with concurrent valorization of wastes. Inclusion of BSF larvae/pupae in the diets of poultry, fish, and swine has shown promise as a potential substitute of conventional feed ingredients such as soybean meal and fish meal. Moreover, the bioactive compounds such as antimicrobial peptides, medium chain fatty acids, and chitin and its derivatives present in BSF larvae/pupae, could also add values to the animal diets. However, to realize the full potential of BSF-based biorefining, more research and development efforts are necessary for scaling up the production and processing of BSF biomass using more mechanized and automated systems. More studies are also needed to ensure the safety of the BSF biomass grown on various organic wastes for animal feed (also food) and legalizing the feed application of BSF biomass to wider categories of animals. This critical review presents the current status of the BSF technology, identifies the research gaps, highlights the challenges towards industrial scale production, and provides future perspectives.

Distribution of T-2 toxin and HT-2 toxin during experimental feeding of yellow mealworm (Tenebrio molitor)

Within the European Union (EU), edible insects need to be approved as "Novel Food" according to Regulation (EU) 2015/2283 and must comply with the requirements of European food law with regard to microbiological and chemical food safety. Substrates used for feeding insects are susceptible to the growth of Fusarium spp. and consequently to contamination with trichothecene mycotoxins. Therefore, the current study aimed to investigate the influence of T-2 and HT-2 toxins on the larval life cycle of yellow mealworm (Tenebrio molitor (L.)) and to study the transfer of T-2, HT-2, T-2 triol and T-2 tetraol in the larvae. In a 4-week feeding study, T. molitor larvae were kept either on naturally (oat flakes moulded with Fusarium sporotrichioides) or artificially contaminated oat flakes, each at two levels (approximately 100 and 250 μg/kg total T-2 and HT-2). Weight gain and survival rates were monitored, and mycotoxins in the feeding substrates, larvae and residues were determined using LC-MS/MS. Larval development varied between the diets and was 44% higher for larvae fed artificially contaminated diets. However, the artificially contaminated diets had a 16% lower survival rate. No trichothecenes were detected in the surviving larvae after harvest, but T-2 and HT-2 were found both in the dead larvae and in the residues of naturally and artificially contaminated diets.

Larvae Mediated Valorization of Industrial, Agriculture and Food Wastes: Biorefinery Concept through Bioconversion, Processes, Procedures, and Products

Each year, the food supply chain produces more than 1.3 billion tons of food and agricultural waste, which poses serious environmental problems. The loss of the massive quantity of secondary and primary metabolites retrievable from this resource is a significant concern. What if there is a global solution that caters to the numerous problems arising due to the humongous volume of waste biomass generated in every part of the world? Insects, the tiny creatures that thrive in decaying organic matter, which can concentrate the nutrients present in dilute quantities in a variety of by-products, are an economically viable option. The bioconversion and nutritional upcycling of waste biomass with insects yield high-value products such as protein, lipids, chitin and frass. Insect-derived proteins can replace conventional protein sources in feed formulations. Notably, the ability of the black soldier fly (BSF) or Hermetia illucens to grow on diverse substrates such as agri-food industry side streams and other organic waste proves advantageous. However, the data on industrial-scale extraction, fractionation techniques and biorefinery schemes for screening the nutritional potential of BSF are scarce. This review attempts to break down every facet of insect processing and analyze the processing methods of BSF, and the functional properties of nutrients obtained thereof.

Tolerance and Removal of Four Polycyclic Aromatic Hydrocarbon Compounds (PAHs) by Black Soldier Fly (Diptera: Stratiomyidae)

Polycyclic aromatic hydrocarbons (PAHs), as well-recognized toxic chemical, cause the public hazard in environments. Here, we demonstrated the black soldier fly larvae (BSFL) could tolerate the PAHs and reduce their content. Four typical PAHs (1.0, 10.0, and 100.0 mg/kg), naphthalene, fluorene, phenanthrene, and pyrene, were individually spiked into BSFL conversion systems. The parameters for larval growth, conversion process, and PAHs removal were determined in spiked group and no-spiked control. The results show that the larval development time (19.7-21.0 d) in the half of PAH groups was significantly longer by 2-4 d than those in the control, while the relative growth rates (1.88-1.99% per day) in the majority PAH groups were lower. The larval mortalities (0-2.83%), harvest yields (80.20-85.91 g), conversion rates (14.71-15.83%), and eclosion rates (60.27-82.67%) in almost all of PAH groups did not significantly different from those in the control. The four PAHs potentially delayed the development time of BSFL, slowed the larval growth, and lower waste reduction rates, but these influences were slight and might be caused by the inhibition of PAHs to microbial activity. The BSFL-mortalities, conversion rates, yields, and eclosion rates were not significantly affected by the PAHs. Furthermore, BSFL effectively removed 34.1-84.2% of PAHs from subtracts in 18-21 d. The removal of PAHs with low concentration could be easier than those with high concentration by BSFL. The present results provide an alternative strategy to treat the waste contaminated by PAHs and elucidate the effect of PAHs on insects in the environment.

The Aspergilli and Their Mycotoxins: Metabolic Interactions With Plants and the Soil Biota

Species of the highly diverse fungal genus Aspergillus are well-known agricultural pests, and, most importantly, producers of various mycotoxins threatening food safety worldwide. Mycotoxins are studied predominantly from the perspectives of human and livestock health. Meanwhile, their roles are far less known in nature. However, to understand the factors behind mycotoxin production, the roles of the toxins of Aspergilli must be understood from a complex ecological perspective, taking mold-plant, mold-microbe, and mold-animal interactions into account. The Aspergilli may switch between saprophytic and pathogenic lifestyles, and the production of secondary metabolites, such as mycotoxins, may vary according to these fungal ways of life. Recent studies highlighted the complex ecological network of soil microbiotas determining the niches that Aspergilli can fill in. Interactions with the soil microbiota and soil macro-organisms determine the role of secondary metabolite production to a great extent. While, upon infection of plants, metabolic communication including fungal secondary metabolites like aflatoxins, gliotoxin, patulin, cyclopiazonic acid, and ochratoxin, influences the fate of both the invader and the host. In this review, the role of mycotoxin producing Aspergillus species and their interactions in the ecosystem are discussed. We intend to highlight the complexity of the roles of the main toxic secondary metabolites as well as their fate in natural environments and agriculture, a field that still has important knowledge gaps.

Deoxynivalenol (DON) Accumulation and Nutrient Recovery in Black Soldier Fly Larvae (Hermetia illucens) Fed Wheat Infected with Fusarium spp

Fusarium head blight (FHB) is one of the most significant causes of economic loss in cereal crops, resulting in a loss of $50–300 million for Canadian agriculture. The infected grain (containing Fusarium-damaged kernels (FDKs)) is often both lower in quality and kernel weight, and it may be unsuitable for human and animal consumption due to mycotoxin presence. However, it still contains a considerable amount of nutrients. A method to recover the nutrients without the mycotoxins should be beneficial for the agricultural economy. In this study, our objective was to examine recovery methods of the nutrients in relation to mycotoxin accumulation in the insect. The FDKs were fermented with Aspergillus oryzae and/or Lactobacillus plantarum (solid-state fermentation (SSF)). The SSF kernels were then provided to 50 young, black soldier fly larvae (BSFL) for 12 days. Weight gain, chemical composition, and mycotoxin bioaccumulation of BSFL and spent feed were evaluated. After 12 days of insect culture, the BSFL grew 5–6 times their initial weight. While the overall weights did not significantly vary, the proteins and lipids accumulated more in SSF FDK-fed insects. During the active growth period, the larval biomass contained deoxynivalenol (DON), a mycotoxin, at detectable levels; however, by day 12, when the larvae were in the pre-pupal stage, the amount of DON in the insect biomass was nearly negligible, i.e., BSFL did not accumulate DON. Thus, we conclude that the combination of BSFL and SSF can be employed to recover DON-free nutrients from FHB-infected grain to recover value from unmarketable grain.

Aflatoxin B1 Conversion by Black Soldier Fly (Hermetia illucens) Larval Enzyme Extracts

The larvae of the black soldier fly (Hermetia illucens L., BSFL) have received increased industrial interest as a novel protein source for food and feed. Previous research has found that insects, including BSFL, are capable of metabolically converting aflatoxin B₁ (AFB₁), but recovery of total AFB₁ is less than 20% when accounting for its conversion to most known metabolites. The aim of this study was to examine the conversion of AFB₁ by S9 extracts of BSFL reared on substrates with or without AFB₁. Liver S9 of Aroclor-induced rats was used as a reference. To investigate whether cytochrome P450 enzymes are involved in the conversion of AFB₁, the inhibitor piperonyl butoxide (PBO) was tested in a number of treatments. The results showed that approximately 60% of AFB₁ was converted to aflatoxicol and aflatoxin P₁. The remaining 40% of AFB₁ was not converted. Cytochrome P450s were indeed responsible for metabolic conversion of AFB₁ into AFP₁, and a cytoplasmic reductase was most likely responsible for conversion of AFB₁ into aflatoxicol.

Impact of Naturally Contaminated Substrates on Alphitobius diaperinus and Hermetia illucens: Uptake and Excretion of Mycotoxins

Insects are considered a suitable alternative feed for livestock production and their use is nowadays regulated in the European Union by the European Commission Regulation No. 893/2017. Insects have the ability to grow on a different spectrum of substrates, which could be naturally contaminated by mycotoxins. In the present work, the mycotoxin uptake and/or excretion in two different insect species, Alphitobius diaperinus (Lesser Mealworm, LM) and Hermetia illucens (Black Soldier Fly, BSF), grown on naturally contaminated substrates, was evaluated. Among all the substrates of growth tested, the Fusarium toxins deoxynivalenol (DON), fumonisin 1 and 2 (FB1 and FB2) and zearalenone (ZEN) were found in those based on wheat and/or corn. No mycotoxins were detected in BSF larvae, while quantifiable amount of DON and FB1 were found in LM larvae, although in lower concentration than those detected in the growing substrates and in the residual fractions. Mass balance calculations indicated that BSF and LM metabolized mycotoxins in forms not yet known, accumulating them in their body or excreting in the faeces. Further studies are required in this direction due to the future employment of insects as feedstuff.

Feeding study for the mycotoxin zearalenone in yellow mealworm (Tenebrio molitor) larvae-investigation of biological impact and metabolic conversion

Edible insects as additional food and/or feed source may represent one important component to solve the problem of food security for a growing human population. Especially for covering the rising demand for protein of animal origin, seven insect species currently allowed as feed constituents in the European Union are gaining more interest. However, before considering insects such as yellow mealworm larvae (Tenebrio molitor) as suitable for, e.g. human consumption, the possible presence and accumulation of contaminants must be elucidated. The present work investigates the effects of the mycotoxin zearalenone (ZEN) and its metabolites on insect larvae. Seven different diets were prepared: toxin-free control, spiked and artificially contaminated (both containing approx.500 μg/kg and approx. 2000 μg/kg of ZEN) as well as two naturally contaminated diets (600 μg/kg and 900 μg/kg ZEN). The diets were used in a multiple-week feeding trial using T. molitor larvae as model insects. The amount of ZEN and its metabolites in the feed, larvae and the residue were measured by HPLC-MS/MS. A significantly enhanced individual larval weight was found for the insects fed on the naturally contaminated diets compared to the other feeding groups after 8 weeks of exposure. No ZEN or ZEN metabolites were detected in the T. molitor larvae after harvest. However, ZEN, α- and β-stereoisomers of zearalenol were found in the residue samples indicating an intense metabolism of ZEN in the larvae. No further ZEN metabolites could be detected in any sample. Thus, ZEN is not retained to any significant amount in T. molitor larvae.

Insects for Food and Feed-Safety Aspects Related to Mycotoxins and Metals

Edible insects as an alternative source of protein are discussed as an important contribution to future feed and food security. However, it has to be ensured that the consumption is non-hazardous. This systematic review summarizes findings concerning contaminations of insects with mycotoxins and heavy metal ions (SciFinder, Pubmed, until 26 June 2019). Both kinds of contaminants were reported to reduce growth performance and increase mortality in insects. There was no evidence for accumulation of various mycotoxins analyzed in distinct insect species. However, further research is necessary due to limitation of data. Since the gut content contributes relevantly to the total body burden of contaminants in insects, a starving period before harvesting is recommended. Contrary, accumulation of heavy metal ions occurred to a varying extent dependent on metal type, insect species, and developmental stage. Examples are the accumulation of cadmium (black soldier fly) and arsenic (yellow mealworm). The reported species-specific accumulation and metabolism patterns of contaminants emphasize the importance to assess potential safety hazards in a case-by-case approach. Subject to regular monitoring of contaminants, the general ban in the European Union to use waste in animal feed should also be questioned regarding insect farming.