Food Safety of Consuming Black Soldier Fly (Hermetia illucens) Larvae: Microbial, Heavy Metal and Cross-Reactive Allergen Risks

Biogas Digestate and Sewage Sludge as Suitable Feeds for Black Soldier Fly (Hermetia illucens) Larvae

Hermetia illucens larvae can use organic wastes as a substrate, which makes them an interesting potential feed. However, waste may contain heavy metals, which are limited in feed. Here, we investigated the ability of H. illucens to grow on organic wastes and measured their heavy metal bioaccumulation. The larvae were fed with food waste, biogas digestates, and sewage sludge. When the first adult fly was visible, the tests were stopped and the larvae immediately processed. The samples (wastes before use, larvae after feeding) were analysed for mineral nutrient and heavy metal content using AAS and ICP-OES, respectively. The results show that the weight of the larvae fed with food waste increased sevenfold, which was broadly in line with expectations. Those fed with sewage sludge and digestate from biogas station increased threefold. While the larvae fed with sewage sludge exceeded the limits for heavy metals, particularly Cd and Pb, in feedstock, those fed with biogas digestate and food waste did not. These findings add to the literature showing the suitability of different wastes as H. illucens feed, and the importance of excluding waste contaminated with heavy metals from larvae intended for use as animal feed, or else diverting these larvae to non-feed uses.

Black soldier fly (Hermetia illucens L.): A potential small mighty giant in the field of cosmeceuticals

Background and Aims

Natural products are widely used in the pharmaceutical and cosmetics industries due to their high-value bioactive compounds, which make for "greener" and more environmentally friendly ingredients. These natural compounds are also considered a safer alternative to antibiotics, which may result in antibiotic resistance as well as unfavorable side effects. The development of cosmeceuticals, which combine the cosmetic and pharmaceutical fields to create skincare products with therapeutic value, has increased the demand for unique natural resources. The objective of this review is to discuss the biological properties of extracts derived from larvae of the black soldier fly (BSF; Hermetia illucens), the appropriate extraction methods, and the potential of this insect as a novel active ingredient in the formulation of new cosmeceutical products. This review also addresses the biological actions of compounds originating from the BSF, and the possible association between the diets of BSF larvae and their subsequent bioactive composition.

Methods

A literature search was conducted using PubMed and Google Scholar to identify and evaluate the various biological properties of the BSF.

Results

One such natural resource that may be useful in the cosmeceutical field is the BSF, a versatile insect with numerous potential applications due to its nutrient content and scavenging behavior. Previous research has also shown that the BSF has several biological properties, including antimicrobial, antioxidant, anti-inflammatory, and wound healing effects.

Conclusion

Given the range of biological activities and metabolites possessed by the BSF, this insect may have the cosmeceutical potential to treat a number of skin pathologies.

Mitigation Strategies against Food Safety Contaminant Transmission from Black Soldier Fly Larva Bioconversion

The black soldier fly larva, Hermetia illucens, can efficiently convert organic waste into biomatter for use in animal feed. This circularity comes with a risk of contaminating downstream consumers of the larval products with microbes, heavy metals, and other hazards potentially present in the initial substrate. This review examines research on mitigation techniques to manage these contaminants, from pretreatment of the substrate to post-treatment of the larvae. While much research has been done on such techniques, little of it focused on their effects on food safety contaminants. Cheap and low-technology heat treatment can reduce substrate and larval microbial load. Emptying the larval gut through starvation is understudied but promising. Black soldier fly larvae accumulate certain heavy metals like cadmium, and their ability to process certain hazards is unknown, which is why some government authorities are erring on the side of caution regarding how larval bioconversion can be used within feed production. Different substrates have different risks and some mitigation strategies may affect larval rearing performance and the final products negatively, so different producers will need to choose the right strategy for their system to balance cost-effectiveness with sustainability and safety.

Evaluation of the Microbial Quality of Hermetia illucens Larvae for Animal Feed and Human Consumption: Study of Different Type of Rearing Substrates

In the context of climate change and depletion of natural resources, meeting the growing demand for animal feed and human food through sufficient, nutritious, safe, and affordable sources of protein is becoming a priority. The use of Hermetia illucens, the black soldier fly (BSF), has emerged as a strategy to enhance the circularity of the agri-food chain, but its microbiological safety remains a concern. The aim of the present study was to systematically review available data on the microbiological quality of BSF and to investigate the impact of using four different rearing substrates including classic options allowed by the EU regulation (cereals, fruits, vegetables) and options not allowed by EU regulations regarding vegetable agri-food (co-products, food at shelf life, and meat). A total of 13 studies were collected and synthesized, including 910 sample results, while 102 new sample results were collected from the present experiments in three farms. Both datasets combined revealed a high level of contamination of larvae, potentially transmitted through the substrate. The main pathogenic bacteria identified were Bacillus cereus, Clostridium perfringens, Cronobacter spp., Escherichia coli, Salmonella spp., and Staphylococcus aureus coagulase-positive, while Campylobacter spp. and Listeria monocytogenes were not detected. Any of these four substrates were excluded for their use in insect rearing; however, safety concerns were confirmed and must be managed by the operators of the sector using microbial inactivation treatment after the harvest of the larvae in order to propose safe products for the market. The results obtained will guide the definition of the control criteria and optimize the following manufacturing steps.

Effect of Pulsed Electric Field Technology on the Composition and Bioactive Compounds of Black Soldier Fly Larvae Dried with Convective and Infrared-Convective Methods

In recent years, an increasing interest has been shown in alternative food sources. Many studies are focused on the use of insects. The aim of this study was to investigate the changes in the chemical and thermal properties of black soldier fly larvae influenced by the pulsed electric field (PEF) and convective (CD) or infrared-convective (IR-CD) drying techniques. Examinations of the basic chemical composition, properties of extracted fat (fatty acid composition, acid and peroxide values, and oxidative stability), total polyphenol content, antioxidant activity, allergen content, and thermogravimetric analysis (TGA) were performed. Generally, the results showed that dried black soldier fly larvae are a good source of protein and fat, up to 33% and 44%, respectively. The fat extracted from the dried insects consisted mainly of saturated fatty acids (above 75%), in particular lauric acid (C12:0). A good oxidative stability of the fat was also observed, especially from samples dried with the IR-CD method. The convective drying technique allowed for better preservation of protein content compared to samples dried with the IR-CD method. Nevertheless, samples treated with PEF were characterized by significantly lower protein content. The samples after PEF pretreatment, with an intensity of 20 and 40 kJ/kg and dried with the IR-CD method, were represented by a significantly higher total polyphenol content and antioxidant activity. Furthermore, in most cases, the convectively dried samples were characterized by a higher allergen content, both crustaceans and mollusks. Taking into account all of the investigated properties, it can be stated that the samples without treatment and those that were PEF-treated with an intensity of 40 kJ/kg and dried with the infrared-convective method (IR-CD) were the most rewarding from the nutritional point of view.

Comparative study of the effects of ultrasound-assisted alkaline extraction on black soldier fly (Hermetia illucens) larvae protein: Nutritional, structural, and functional properties

In this study, we developed an ultrasound-assisted alkaline method for extracting black soldier fly larvae protein (BSFLP). The effects of ultrasound-assisted extraction on the nutritional value, structural characteristics, and techno-functional properties of BSFLP were compared with those using the conventional hot alkali method. The results showed that ultrasound-assisted extraction significantly increased the extraction ratio of BSFLP from 55.40% to 80.37%, but reduced the purity from 84.19% to 80.75%. The BSFLP extracted by ultrasound-assisted extraction met the amino acid requirements for humans proposed by the Food and Agriculture Organization in 2013, and ultrasound-assisted extraction did not alter the limiting amino acids of the BSFLP. The ultrasound-assisted extraction increased the in vitro protein digestibility from 82.97% to 99.79%. Moreover, ultrasound-assisted extraction obtained BSFLP with a more ordered secondary structure and more loosely porous surface morphology, without breaking the peptide bonds. By contrast, the conventional hot alkaline method hydrolyzed BSFLP into smaller fragments. The effect of ultrasound-assisted extraction on the structure of BSFLP improved the solubility and emulsion capacity of BSFLP, but reduced its foaming properties. In conclusion, the results of this study suggest that ultrasound-assisted alkaline extraction could be a suitable method for extracting BSFLP and improving its nutritional value, and structural and functional properties. The findings obtained in this study could promote the wider application of BSFLP in food industry.

Legal situation and consumer acceptance of insects being eaten as human food in different nations across the world-A comprehensive review

Insect consumption is a traditional practice in many countries. Currently, the urgent need for ensuring food sustainability and the high pressure from degrading environment are urging food scientists to rethink the possibility of introducing edible insects as a promising food type. However, due to the lack of the standardized legislative rules and the adequate scientific data that demonstrate the safety of edible insects, many countries still consider it a grey area to introduce edible insects into food supply chains. In this review, we comprehensively reviewed the legal situation, consumer willingness, acceptance, and the knowledge on edible insect harvesting, processing as well as their safety concerns. We found that, despite the great advantage of introducing edible insects in food supply chains, the legal situation and consumer acceptance for edible insects are still unsatisfactory and vary considerably in different countries, which mostly depend on geographical locations and cultural backgrounds involving psychological, social, religious, and anthropological factors. Besides, the safety concern of edible insect consumption is still a major issue hurdling the promotion of edible insects, which is particularly concerning for countries with no practice in consuming insects. Fortunately, the situation is improving. So far, some commercial insect products like energy bars, burgers, and snack foods have emerged in the market. Furthermore, the European Union has also recently issued a specific item for regulating new foods, which is believed to establish an authorized procedure to promote insect-based foods and should be an important step for marketizing edible insects in the near future.

Upcycling of recycled minerals from sewage sludge through black soldier fly larvae (Hermetia illucens): Impact on growth and mineral accumulation

Phosphorous (P) resources are finite. Sewage sludge recyclates (SSR) are not only of interest as plant fertilizer but also as potential source of minerals in animal nutrition. However, besides P and calcium (Ca), SSR contain heavy metals. Under EU legislation, the use of SSR derivatives in animal feed is not permitted, but given the need to improve nutrient recycling, it could be an environmentally sound future mineral source. Black soldier fly larvae (BSFL) convert low-grade biomass into valuable proteins and lipids, and accumulate minerals in their body. It was hypothesized that BSFL modify and increase their mineral content in response to feeding on SSR containing substrates. The objective was to evaluate the upcycling of minerals from SSR into agri-food nutrient cycles through BSFL. Growth, nutrient and mineral composition were compared in BSFL reared either on a modified Gainesville fly diet (FD) or on FD supplemented with either 4% of biochar (FD + BCH) or 3.6% of single-superphosphate (FD + SSP) recyclate (n = 6 BSFL rearing units/group). Larval mass, mineral and nutrient concentrations and yields were determined, and the bioaccumulation factor (BAF) was calculated. The FD + SSP substrate decreased specific growth rate and crude fat of BSFL (P < 0.05) compared to FD. The FD + SSP larvae had higher Ca and P contents and yields but the BAF for Ca was lowest. The FD + BCH larvae increased Ca, iron, cadmium and lead contents compared to FD. Larvae produced on FD + SSP showed lower lead and higher arsenic concentration than on FD + BCH. Frass of FD + BCH had higher heavy metal concentration than FD + SSP and FD (P < 0.05). Except for cadmium and manganese, the larval heavy metal concentration was below the legally permitted upper concentrations for feed. In conclusion, the SSR used could enrich BSFL with Ca and P but at the expense of growth. Due to the accumulation of Cd and Mn, BSFL or products thereof can only be a component of farmed animal feed whereas in BSFL frass heavy metal concentrations remained below the upper limit authorized by EU.

Near Infrared Spectroscopy for Prediction of Yeast and Mould Counts in Black Soldier Fly Larvae, Feed and Frass: A Proof of Concept

The use of black soldier fly larvae (BSFL) grown on different organic waste streams as a source of feed ingredient is becoming very popular in several regions across the globe. However, information about the easy-to-use methods to monitor the safety of BSFL is a major step limiting the commercialization of this source of protein. This study investigated the ability of near infrared (NIR) spectroscopy combined with chemometrics to predict yeast and mould counts (YMC) in the feed, larvae, and the residual frass. Partial least squares (PLS) regression was employed to predict the YMC in the feed, frass, and BSFL samples analyzed using NIR spectroscopy. The coefficient of determination in cross validation (R2CV) and the standard error in cross validation (SECV) obtained for the prediction of YMC for feed were (R2cv: 0.98 and SECV: 0.20), frass (R2cv: 0.81 and SECV: 0.90), larvae (R2cv: 0.91 and SECV: 0.27), and the combined set (R2cv: 0.74 and SECV: 0.82). However, the standard error of prediction (SEP) was considered moderate (range from 0.45 to 1.03). This study suggested that NIR spectroscopy could be utilized in commercial BSFL production facilities to monitor YMC in the feed and assist in the selection of suitable processing methods and control systems for either feed or larvae quality control.

Nudging Consumer Behavior with Social Marketing in Portugal: Can Perception Have an Influence over Trying Insect-Based Food?

Social marketing campaigns are widely used to inform, educate, communicate, and promote healthy behaviors that add benefits to the individual, but also to society and the environment. Considering the low cost and high quality of insect-based food, this research aims to identify the main factors which can be used by social marketing campaigns to help people to try new foods, such as insect-based food. Although it is considered an important alternative to protein, there are a few countries that have not experienced it. In many Western countries, insect-based food is perceived as being disgusting. Neophobia is also a barrier to trying these foods. The main goal is to analyze if social marketing campaigns might influence perception (familiarity, preparation, visual, and information). Our model proves this assumption because we obtained high path coefficients, indicating that perception influences social beliefs, individual beliefs, and consumption intention. Thus, they will increase the consumption intention.

Early Growth Patterns of Bacillus cereus on Potato Substrate in the Presence of Low Densities of Black Soldier Fly Larvae

Bacillus cereus is a common and ubiquitous bacterium that can cause foodborne illnesses in humans and other animals. Common methods of contact between foodborne pathogens and their victims include exposure through contaminated food or food containment products. Using larvae of black soldier flies, Hermetia illucens, for biological conversion of wastes into components of animal feeds is a rapidly growing technology. However, contamination of larval biomass with pathogenic microorganisms may challenge its use on an industrial scale. We conducted laboratory experiments to test the effects of the black soldier fly larvae developing on simulated potato waste substrate on B. cereus abundance. We observed a general increase in the number of colony-forming units and concentration of hblD - gene when the larvae were present in the substrate, although the effect was modulated by larval densities and time since inoculation. It is possible that starch breakdown by black soldier fly larvae may provide a beneficial environment for B. cereus. Our results differ from the suppression in the presence by black soldier fly larvae reported for several other bacterial species and highlight the importance of taking proper food safety measures when using this technology.

Effects of Hermetia illucens larvae meal on the Pacific white shrimp (Litopenaeus vannamei) revealed by innate immunity and 16S rRNA gene sequencing analysis

The larvae of the black soldier fly, Hermetia illucens, are now attracting attention and becoming promising sources for aquafeed ingredient due to the nutritious substance. However, the introduction of a novel ingredient into the recipe may have unpredictable effects on the innate immune function and gut bacteria composition of crustaceans. Therefore, the present study aimed to evaluate how dietary black soldier fly larvae meal (BSFLM) affected the antioxidant ability, innate immunity and gut microbiome of shrimp (Litopenaeus vannamei) fed with a practical diet, including the gene expression of Toll and immunodeficiency (IMD) pathways. Six experimental diets were formulated by replacing gradient levels of fish meal (0 %, 10 %, 20 %, 30 %, 40 % and 50 %) based on a commercial shrimp diet. Four replicates of shrimp were fed different diets three times daily for 60 days. Growth performance linearly decreased with increasing BSFLM inclusion. Results of antioxidative enzyme activities and gene expression suggested that low dietary BSFLM levels activated the antioxidant capacity of shrimp, while dietary BSFLM levels up to 100 g/kg may induce oxidative stress and inhibit glutathione peroxidase activity. Although traf6, toll1, dorsal and relish were significantly upregulated in different BSFLM groups, the expression of tak1 was significantly downregulated in groups containing BSFLM, implying the immune susceptibility may be weakened. Gut flora analysis indicated dietary BSFLM altered both beneficial and opportunistic pathogenic bacterial abundance, with low levels of dietary BSFLM increased the abundance of bacteria that may contribute to carbohydrate utilization, while high levels of dietary BSFLM may cause intestinal disease and low intestinal immune response. To conclude, 60-80 g/kg of dietary BSFLM showed no adverse effects on the growth, antioxidant capacity and gut flora of shrimp, which was the adequate level in shrimp diet. While 100 g/kg dietary BSFLM may induce oxidative stress and potentially weaken the innate immunity of shrimp.

Effects of Drying Methods and Blanching on Nutrient Utilization in Black Soldier Fly Larva Meals Based on In Vitro Assays for Pigs

The objective was to determine the effects of drying and blanching methods on the nutrient utilization of black soldier fly larva (BSFL; Hermetia illucens) meal by pigs using in vitro assays. Two-step and three-step in vitro assays were employed to simulate the gastrointestinal tract of pigs. Four BSFL meals were prepared using the following pretreatment methods: (1) microwave drying at 80 °C for 32 min, (2) hot-air drying at 60 °C for 17 h, (3) blanching for 5 min in boiling water and hot-air drying at 60 °C for 17 h, and (4) 2% citric acid solution blanching for 5 min in boiling solution and hot-air drying at 60 °C for 17 h. After the drying process, each BSFL was defatted and ground to obtain BSFL meals. The nitrogen (N) concentration in the test ingredients ranged from 8.5 to 9.4%, and the ether extract ranged from 6.9 to 11.5% on an as-is basis. The amino acid (AA) concentration in the BSFL meals ranged from 2.80 to 3.24% for Lys and 0.71 to 0.89% for Met on an as-is basis. Hot-air-dried BSFL meal had a greater in vitro ileal disappearance (IVID) of N compared with microwave-dried BSFL meal (p < 0.05). However, blanched BSFL meals in water or 2% citric acid solution before hot-air drying had a lower (p < 0.05) IVID of N compared with microwave-dried or hot-air-dried BSFL meal. Blanched BSFL meals in water or 2% citric acid solution before hot-air drying showed a lower (p < 0.05) in vitro total tract disappearance of dry matter and organic matter compared with microwave-dried or hot-air-dried BSFL meal. Microwave-dried BSFL meal had a lower (p < 0.05) IVID of indispensable AA, except for His, Lys, Met, and Phe, compared with hot-air-dried BSFL meals. However, blanched BSFL meals in water or 2% citric acid solution before hot-air drying showed a lower (p < 0.05) IVID of indispensable AA compared with microwave-dried or hot-air-dried BSFL meal. In conclusion, hot-air-dried BSFL meal presented greater nutrient utilization compared with microwave-dried BSFL meal for pigs. However, blanching in water or citric acid solution negatively affected the nutrient digestibility of BSFL meal based on in vitro assays.

Black soldier fly, Hermetia illucens as a potential innovative and environmentally friendly tool for organic waste management: A mini-review

The application of black soldier fly (BSF), Hermetia illucens based technology to process organic wastes presents a practical option for organic waste management by producing feed materials (protein, fat), biodiesel, chitin and biofertilizer. Therefore, BSF organic wastes recycling is a sustainable and cost-effective process that promotes resource recovery, and generates valuable products, thereby creating new economic opportunities for the industrial sector and entrepreneurs. Specifically, we discussed the significance of BSF larvae (BSFL) in the recycling of biowaste. Despite the fact that BSFL may consume a variety of wastes materials, whereas, certain lignocellulosic wastes, such as dairy manure, are deficient in nutrients, which might slow BSFL development. The nutritional value of larval feeding substrates may be improved by mixing in nutrient-rich substrates like chicken manure or soybean curd residue, for instance. Similarly, microbial fermentation may be used to digest lignocellulosic waste, releasing nutrients that are needed for the BSFL. In this mini-review, a thorough discussion has been conducted on the various waste biodegraded by the BSFL, their co-digestion and microbial fermentation of BSFL substrate, as well as the prospective applications and safety of the possible by-products that may be generated at the completion of the treatment process. Furthermore, this study examines the present gaps and challenges on the direction to the efficient application of BSF for waste management and the commercialization of its by-products.

The Variety of Applications of Hermetia illucens in Industrial and Agricultural Areas-Review

Hermetia illucens (Diptera: Stratiomyidae, Linnaeus, 1978), commonly known as the black soldier fly (BSF), is a saprophytic insect, which in recent years has attracted significant attention from both the scientific community and industry. The unrestrained appetite of the larvae, the ability to forage on various organic waste, and the rapid growth and low environmental impact of its breeding has made it one of the insect species bred on an industrial scale, in the hope of producing fodder or other ingredients for various animals. The variety of research related to this insect has shown that feed production is not the only benefit of its use. H. illucens has many features and properties that could be of interest from the point of view of many other industries. Biomass utilization, chitin and chitosan source, biogas, and biodiesel production, entomoremediation, the antimicrobial properties of its peptides, and the fertilizer potential of its wastes, are just some of its potential uses. This review brings together the work of four years of study into H. illucens. It summarizes the current state of knowledge and introduces the characteristics of this insect that may be helpful in managing its breeding, as well as its use in agro-industrial fields. Knowledge gaps and under-studied areas were also highlighted, which could help identify future research directions.

Preliminary Data on Essential and Non-essential Element Occurrence in Processed Animal Proteins from Insects

Insects represent a valuable and environmentally friendly protein alternative in food and feed. The Farm to Fork strategy encouraged the reintroduction of animal by-products in feed production to optimise recycling and to valorise under-used resources. In order to grant safe and valuable feed products, this study investigated the black soldier fly (BSF) (Hermetia illucens) chemical risk. Samples collected in different steps of production (8 samples of substrate for culturing, 7 samples of larvae, 15 samples of protein meal, 18 samples of spent substrate) were analysed for microessential elements (chromium, copper, iron, nickel, selenium and zinc) and inorganic contaminants (aluminium, arsenic, cadmium, lead, tin and vanadium) by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). Microessential elements were found in the following order: Fe > Zn > Cu > Ni > Se > Cr (mg kg^-1). Non-essential element concentrations were found lower than the set limits according to the European Union Regulations. The growing demand for alternative protein sources for feed production could be partially compensated by black soldier fly (BSF) (Hermetia illucens) meal, as it appears a good source for high-quality proteins and microessential elements which play a pivotal role in animal growth. In the foreseeable future the current legislation and the official monitoring plans may be implemented and broaden, to focus and assess limits for upcoming matrices, and to ensure feed and food safety.

Food waste and soybean curd residue composting by black soldier fly

This study attempted to manage the food waste and soybean curd residue generated in Taiwan's National Ilan University by black soldier fly-aided co-composting. The food waste and soybean curd residue were co-composted with rice husk as a bulking agent in 4:1 ratio and 0.42 mg BSF/g waste. The higher organic matter degradation of 31.9% was found in Container B (black soldier flies aided food waste and rice husk co-composting) with a rate constant of 0.14 d-1. In Container D (black soldier flies aided soybean curd residue and rice husk co-composting), the organic matter degradation of 29.4% was found with a rate constant of 0.29 d-1. The matured compost of 6.02 kg was obtained from 20 kg of food waste, while 5.83 kg of matured compost was generated from 20 kg of soybean curd residue. The physico-chemical parameters of the final matured compost were in the favorable range of Taiwan's compost standards. The germination index was 188.6% and 194.78% in Containers B and D, respectively. The present study will expand the application of BSF at the institutional level which prove to be a feasible solution for rapid, clean, and efficient composting of post-consumer food wastes.

Suppression of Methicillin-Resistant Staphylococcus aureus and Reduction of Other Bacteria by Black Soldier Fly Larvae Reared on Potato Substrate

Larvae of black soldier flies, Hermetia illucens, are increasingly used for biological conversion of animal and plant wastes into ingredients of animal feeds on an industrial scale. The presence of pathogenic microorganisms in harvested larvae may be a serious problem for wide-scale adoption of this technology. Fortunately, black soldier fly larvae may have some antimicrobial properties. Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium associated with various environments that can be pathogenic to humans and farmed animals. We tested whether black soldier fly larvae suppress MRSA on potato substrate. Autoclaved potatoes containing black soldier fly larvae (P+BSFL), potatoes inoculated with MRSA and containing black soldier fly larvae (P+MRSA+BSFL), and potatoes inoculated with MRSA (P+MRSA) were incubated in glass jars. Substrate samples were taken after 3 and 7 days of incubation and plated on Trypticase soy agar (TSA) and Staphylococcus medium 110 agar (SA) to quantify total bacteria and MRSA, respectively. DNA was extracted from potato substrates on both days and sequenced to assess bacterial and fungal diversity using 515F/806R and internal transcribed spacer (ITS) 1/2 primers, respectively, and QIIME 2.0 software. Both total bacterial and MRSA-specific CFU were reduced in the presence of black soldier fly larvae, with a larger reduction for the latter. Twenty-five bacterial genera and 3 fungal genera were detected. Twenty bacterial genera were shared among the treatments and the days, but their relative abundances often varied. Among the most abundant genera, only Enterococcus and Lactococcus were universally present. Our findings confirm antimicrobial properties of black soldier fly larvae. IMPORTANCE Larvae of black soldier flies, Hermetia illucens, may be used to provide an environmentally sustainable and economically viable method for biological conversion of animal and plant wastes into ingredients of animal feeds on an industrial scale. However, contamination of harvested larvae by pathogenic microorganisms inhabiting decaying substrates may be a serious problem for wide-scale adoption of this technology. Fortunately, black soldier fly larvae may have some antimicrobial properties, including suppression of several common pathogens. Our study showed that such a suppression applies to methicillin-resistant Staphylococcus aureus, which is a ubiquitous bacterium pathogenic to animals (including humans).

Insects in Pet Food Industry-Hope or Threat?

Due to the increasing global population, the world cannot currently support the well-known techniques of food production due to their harmful effects on land use, water consumption, and greenhouse gas emissions. The key answer is a solution based on the use of edible insects. They have always been present in the diet of animals. They are characterized by a very good nutritional value (e.g., high protein content and contents of essential amino acids and fatty acids, including lauric acid), and products with them receive positive results in palatability tests. Despite the existing literature data on the benefits of the use of insects as a protein source, their acceptance by consumers and animal caregivers remains problematic. In spite of the many advantages of using insects in pet food, it is necessary to analyze the risk of adverse food reactions, including allergic reactions that may be caused by insect consumption. Other hazards relate to the contamination of insects. For example, they can be contaminated with anthropogenic factors during breeding, packaging, cooking, or feeding. These contaminants include the presence of bacteria, mold fungi, mycotoxins, and heavy metals. However, insects can be used in the pet food industry. This is supported by the evolutionary adaptation of their wild ancestors to the eating of insects in the natural environment. The chemical composition of insects also corresponds to the nutritional requirements of dogs. It should be borne in mind that diets containing insect and their effects on animals require careful analysis. The aim of this article is to discuss the nutritional value of insects and their possible applications in the nutrition of companion animals, especially dogs.

A Review of Organic Waste Treatment Using Black Soldier Fly (Hermetia illucens)

The increase in solid waste generation is caused primarily by the global population growth that resulted in urban sprawl, economic development, and consumerism. Poor waste management has adverse impacts on the environment and human health. The recent years have seen increasing interest in using black soldier fly (BSF), Hermetia illucens, as an organic waste converter. Black soldier fly larvae (BSFL) feed voraciously on various types of organic waste, including food wastes, agro-industrial by-products, and chicken and dairy manure, and reduce the initial weight of the organic waste by about 50% in a shorter period than conventional composting. The main components of the BSFL system are the larvero, where the larvae feed and grow, and the fly house, where the adults BSF live and reproduce. It is essential to have a rearing facility that maintains the healthy adult and larval BSF to provide a sufficient and continuous supply of offspring for organic waste treatment. The BSF organic waste processing facility consists of waste pre-processing, BSFL biowaste treatment, the separation of BSFL from the process residue, and larvae and residue refinement into marketable products. BSFL digest the nutrients in the wastes and convert them into beneficial proteins and fats used to produce animal feed, and BSFL residue can be used as an organic fertilizer. This review summarizes the BSFL treatment process to provide an in-depth understanding of the value of its by-products as animal feed and organic fertilizer.

The Effect of Rearing Scale and Density on the Growth and Nutrient Composition of Hermetia illucens (L.) (Diptera: Stratiomyidae) Larvae

With the worldwide industrialization of black soldier fly (BSF) production, it is necessary to better understand how the rearing scale and larvae density influence the performance of larvae and the quality of the final product. In this study, a factorial experiment was conducted to test the effect of rearing scale and density on the growth and composition of the BSF larvae. The larvae were grown in four different scales (box sizes), keeping the area and feed provided to each larva constant and in two different densities. The results reveal significant differences in the larval growth depending on the scale and density, which could be attributed to the higher temperatures achieved in the bigger scales with a temperature difference of more than 5 °C between the smallest and the biggest scale. Both the scale and the density influenced the composition of the larvae. The crude protein levels were higher on the smallest scale, and the lower density (ranging from 32.5% to 36.5%), and crude fat concentrations were the opposite (ranging from 31.7% to 20.1%). The density also influenced the concentrations of S, Mg, K, P, Fe, Zn, Cu, Al, B, and Co, in addition to the analyzed free amino acids PPS, ALA, CIT, and ANS. Furthermore, the rearing scale influenced the concentration of S, Zn, Cu, and Mo. The results provide further insight into the optimization of BSF production processes and the transfer of lab-scale results into big-scale production.