Nutritional composition and safety aspects of edible insects

Cross-allergenicity of crustacean and the edible insect Gryllus bimaculatus in patients with shrimp allergy

Food scarcity is a serious problem for many developing as well as developed countries. Edible insects have attracted attention recently as a novel food source. Crickets are especially high in nutritional value and easy to breed and harvest. In this study, we evaluated the risk of allergic reactions associated with cricket consumption in individuals with crustacean allergy. We evaluated food allergy risk in the consumption of Gryllus bimaculatus (cricket) in patients with shrimp allergy, using enzyme-linked immunosorbent assay (ELISA) and IgE crosslinking-induced luciferase expression assay (EXiLE). Sera from individuals with shrimp allergy (positive for shrimp-specific IgE by ImmunoCAP (>0.35 UA/mL; n = 9) or without shrimp allergy (negative for shrimp-specific IgE; n = 6) were obtained. There was a strong correlation between shrimp- and Gryllus-specific IgE levels obtained by ELISA (r_s = 0.99; P <  0.001). The binding of shrimp-specific IgE on shrimp allergen was dose-dependently inhibited by Gryllus allergen (0-1.0 mg/mL). There was a strong correlation between shrimp- and Gryllus-specific IgE responses, as assessed by EXiLE assays (r_s = 0.89; P < 0.001). We determined that a protein of approximately 40 kDa reacted with the positive, but not negative, sera for shrimp-specific IgE by ImmunoCAP. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis identified the major allergen in shrimp and Gryllus to be tropomyosin. Our data suggest that the cricket allergen has the potential to induce an allergic reaction in individuals with crustacean allergy. Therefore, allergy risk and shrimp-specific IgE levels should be considered before consumption of cricket meal.

Determination of vitamin B12 in four edible insect species by immunoaffinity and ultra-high performance liquid chromatography

Insects are rich in major nutrients, such as protein and fat. Recently, minor nutrients like vitamins have become the subjects of interest in insects. Hence, this study reports on the development and validation of a method for the determination of vitamin B₁₂ in mealworm (Tenebrio molitor larvae), cricket (Gryllus assimilis), grasshopper (Locusta migratoria) and cockroach (Shelfordella lateralis), using an ultra-high performance liquid chromatography approach with preliminary immunoaffinity chromatography sample preparation. The method was validated regarding linearity, specificity, accuracy and precision, as well as limits of detection/quantification, and was found to be satisfactory for the desired application. Found levels of vitamin B₁₂ were 1.08 µg/100 g for mealworm, 2.88 µg/100 g for cricket, 0.84 µg/100 g for grasshopper, and 13.2 µg/100 g dry weight for cockroach, representing the first validated report on the content of vitamin B₁₂ in edible insects. Observed interferences are likely caused by the presence of pseudovitamin B₁₂.

Effects of waste stream combinations from brewing industry on performance of Black Soldier Fly, Hermetia illucens (Diptera: Stratiomyidae)

BACKGROUND

In recent years, there has been a rapidly growing demand for readily accessible substrates for mass production of Black Soldier Fly, Hermetia illucens Linnaeus. Beer production results in various by-products that typically end up in uncontrolled dumpsites constituting pollution problems, which merits urgent attention. The present study investigated whether the 12 formulated diets composed of brewers' spent grains (BSGs), brewers' yeast and cane molasses can serve as substrate for H. illucens production.

METHODS

Four different BSGs were selected and formulated into 12 diets, aiming at varying protein and net energy levels. The diets were offered to newly hatched (∼1 h old) H. illucens larvae and the influence on developmental duration, survival, wet weight, pre-oviposition time, fecundity, and longevity were compared.

RESULTS

Developmental duration of the larvae (16-21 days) and pre-pupae (8-11 days) differed significantly across the different diets. The developmental duration of the pupae (8.7-9.1 days) was not affected by diet. The larval (86-99.2%), pre-pupal (71-95%), and pupal (65-91%) survival rates varied significantly between flies reared on the different diets. The pre-oviposition time was similar for flies provided with water (7-11 days) and 10% sugar solution (8-14 days) or across the different diets. The mean fecundity per female ranged from 324-787 eggs and did not differ between females provided with water or sugar solution. However, the number of eggs laid per female varied significantly across the different diets when provided with water. The longevity of starved H. illucens adults was significantly lower (5 days) compared to those provided with water (11-14 days) or sugar solution (14-15 days).

DISCUSSION

The implications of these findings as part of a quality control procedure for commercial production of high-quality H. illucens larvae as an alternative protein ingredient in livestock and aquaculture feed are discussed.

Threshold temperatures and thermal requirements of black soldier fly Hermetia illucens: Implications for mass production

Efforts to recycle organic wastes using black soldier fly (BSF) Hermetia illucens into high-nutrient biomass that constitutes a sustainable fat (biodiesel) and high-quality protein ingredient in animal feeds have recently gained momentum worldwide. However, there is little information on the most suitable rearing conditions for growth, development and survivorship of these flies, which is a prerequisite for mass production technologies. We evaluated the physiological requirements for growth and reproduction of H. illucens on two diets [spent grains supplemented with brewers’ yeast (D1) and un-supplemented (D2)]. Development rates at nine constant temperatures (10–42°C) were fitted to temperature-dependent linear and non-linear day-degree models. Thereafter, life history table parameters were determined within a range of favourable temperatures. The thermal maximum (TM) estimates for larval, pre-pupal and pupal development using non-linear model ranged between 37.2 ± 0.3 and 44.0 ± 2.3°C. The non-linear and linear day-degree model estimations of lower developmental temperature threshold for larvae were 11.7 ± 0.9 and 12.3 ± 1.4°C for D1, and 10.4 ± 1.7 and 11.7 ± 3.0°C for D2, respectively. The estimated thermal constant of immature life stages development of BSF was higher for the larval stage (250±25 DD for D1 and 333±51 for D2) than the other stages evaluated. Final larval wet weight was higher on D1 compared to D2. The population growth rate was most favourable at 30-degree celsius (°C) with higher intrinsic rate of natural increase (r_m = 0.127 for D1 and 0.122 for D2) and shorter doubling time (5.5 days for D1 and 5.7 days for D2) compared to the other temperatures. These results are valuable for the optimization of commercial mass rearing procedures of BSF under various environmental conditions and prediction of population dynamics patterns using computer simulation models.

When Utilitarian Claims Backfire: Advertising Content and the Uptake of Insects as Food

A key challenge for climate change mitigation on the consumer side is to break habits that excessively lead to carbon emission. One of the culturally most robust human routines is the heavy reliance of the Western societies on conventional meat sources such as beef, pork, and poultry, which were recently accused of causing particularly high climate costs. In this light, the UN (FAO) has suggested the increasing use of insects as an alternative source of animal protein intended for human diets. Yet, insects have not reached the mainstream of Western cuisine. Currently, a frequent promotion strategy of insects is to highlight the Utilitarian benefits associated with their consumption (e.g., with respect to the environment or one's health). The present research addresses the efficacy of such claims in a consumer research study involving 180 participants recruited from the general population in Germany. Arguing based on social-cognitive research in the area of moral and environmental psychology, we hypothesized and found that a focus on beneficial, but temporally distant motives (e.g., health)—counterintuitively—decreases consumption in comparison to immediate, hedonic advertisements (e.g., tasty). Furthermore, our study provides process evidence suggesting pretrial expectations induced by a particular claim mediate the relationship between claims and consumption. Thus, the present research not only refutes a state-of-the-art approach in the promotion of insects as food, but also provides an alternative approach and process evidence by integrating psychological factors.

Comparison of the nutritional content of the captive and wild diets of the critically endangered mountain chicken frog (Leptodactylus fallax) to improve its captive husbandry

It is vital to provide appropriate nutrition to maintain healthy populations in conservation breeding programs. Knowledge of the wild diet of a species can be used to inform captive diet formulation. The nutritional content of the wild diet of the critically endangered mountain chicken frog (Leptodactylus fallax) is unknown, like that of most amphibians. In this study, we analyzed the nutritional content of food items that comprise 91% of the wild diet of L. fallax, by dry weight of food items, and all food items offered to captive L. fallax at ZSL London Zoo and Jersey Zoo. We subsequently compared the nutritional content of the wild diet and captive diet at ZSL London Zoo consumed by L. fallax. To the authors' knowledge, this is the first study to directly compare the nutritional content of the wild and captive diets of an anuran amphibian. The captive diet at ZSL London Zoo, without dusting of nutritional supplements, was higher in gross energy and crude fat and lower in ash, calcium and calcium:phosphorus ratio than the wild diet. Most of the food items in the captive diets had a high omega-6:omega-3 fatty acid ratio and in the wild diet had a low omega-6:omega-3 fatty acid ratio. We recommend a combination of modifications to the captive diets to better reflect the nutritional content of the wild diet. Nutritional analysis of captive and wild diets is recommended for other species in conservation breeding programs to improve captive husbandry and ultimately fitness.

Traditional knowledge regarding edible insects in Burkina Faso

BACKGROUND

Insects play an important role as a diet supplement in Burkina Faso, but the preferred insect species vary according to the phytogeographical zone, ethnic groups, and gender. The present study aims at documenting indigenous knowledge on edible insects in Burkina Faso.

METHODS

A structured ethno-sociological survey was conducted with 360 informants in nine villages located in two phytogeographical zones of Burkina Faso. Identification of the insects was done according to the classification of Scholtz. Chi-square tests and principal component analysis were performed to test for significant differences in edible insect species preferences among phytogeographical zones, villages, ethnic groups, and gender.

RESULTS

Edible insects were available at different times of the year. They were collected by hand picking, digging in the soil, and luring them into water traps. The edible insects collected were consumed fried, roasted, or grilled. All species were indifferently consumed by children, women, and men without regard to their ages. A total of seven edible insect species belonging to five orders were cited in the Sudanian zone of Burkina Faso. Macrotermes subhyalinus (Rambur), Cirina butyrospermi (Vuillet, 1911), Kraussaria angulifera (Krauss, 1877), Gryllus campestris (Linnaeus, 1758), and Carbula marginella (Thunberg) (35.66-8.47% of the citations) were most cited whereas Rhynchophorus phoenicis (Fabricius, 1801) and Oryctes sp. (3.41-0.27%) were least cited. Cirina butyrospermi was most cited in the South Sudanian zone, whereas Macrotermes subhyalinus and Kraussaria angulifera were most cited in the North Sudanian zone but were cited in all nine villages. Cirina butyrospermi was preferred by Bobo, Guin, Sambla, Senoufo, and Turka ethnic groups whereas Macrotermes subhyalinus was preferred by Fulani, Mossi, and Toussian ethnic groups. Oryctes sp. was cited only by the Toussian.

CONCLUSION

A diversity of edible insects was consumed in both the South and North Sudanian zone of Burkina Faso with significant differences in species preferences according to phytogeographical zones, villages, ethnic groups, and gender.

A Set of Multiplex Polymerase Chain Reactions for Genomic Detection of Nine Edible Insect Species in Foods

On 1 January 2018, a new regulation on 'Novel Food' has come into application in the EU. Insects and insect-based products are therefore included among the categories of food which constitute novel foods. Insects are nutrient-rich, produce fewer greenhouse gases and ammonia than conventional livestock, and have high feed conversion efficiency. Insects may be an alternative food source in the near future, but consideration of insects as a food requires scrutiny due to the risk of allergens. The aim of the present study was to develop a set of multiplex polymerase chain reaction (PCR) to detect nine edible insect species directly in foods. Four sets of mPCRs were designed to detect Locusta migratoria migratorioides (Reiche & Fairmaire, 1849) (Orthoptera: Acrididae), Tenebrio molitor (Linnaeus, 1758) (Coleoptera: Tenebrionidae) (mPCR-I), Acheta domesticus (Linnaeus, 1758) (Orthoptera: Gryllidae), Bombyx mori (Linnaeus, 1758) (Lepidoptera: Bombycidae (mPCR-II), Alphitobius diaperinus (Panzer, 1797) (Coleoptera: Tenebrionidae), Schistocerca gregaria (Forskål, 1775) (Orthoptera: Acrididae), Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae) (mPCR-III), Galleria mellonella (Linnaeus, 1758) (Lepidoptera: Pyralidae), and Gryllodes sigillatus (Walker, 1869) (Orthoptera: Gryllidae) (mPCR-IV). Results demonstrate that the panel of mPCRs allowed a rapid genetic identification of the insect species and has proved to be a sensible and highly discriminatory method. The assay is a potential tool in issues related to the labeling of products and food safety, in case of allergic consumers.

Beetles, ants, wasps, or flies? An ethnobiological study of edible insects among the Awajún Amerindians in Amazonas, Peru

BACKGROUND

Insects are known to be able to provide valuable nutrients to indigenous populations across the Amazon. However, studies on traditional insect use in the Peruvian Amazon are scarce. This study documents edible insect diversity and characterizes their food and collection patterns in eight Awajún communities in the Peruvian Amazon. Additionally, we reviewed what has been known to date about the nutrient composition of the documented species.

METHODS

The survey was conducted among the Awajún populations living in the Huampami, Paisa, Achu, and Tseasim communities in the Cenepa district and the Shijap, San Mateo, Kusu, and Listra communities in the Imaza district. Data collection was conducted through a freelisting exercise complemented by a semi-structured inquiry form in the Awajún language. In total, 104 informants (72 men and 32 women) aged between 16 to 73 years were interviewed.

RESULTS

The Awajún people use at least 12 insect species, with Rhynchophorus palmarum, Atta cephalotes, and Rhinostomus barbirostris being the most important ones. Beetles of the family Curculionidae represent the culturally most salient taxon. In the more accessible and developed Imaza district, the Awajún tend to eat almost exclusively R. palmarum, while in the more isolated and preserved Cenepa district, the community's preferences are linked with more species. Although men are the main insect collectors, women cited more edible insects on average. The insects are eaten mainly roasted or raw. Further use patterns and differences between the districts are discussed.

CONCLUSION

Traditional knowledge related to edible insects and the ecosystems they occur in is widespread among the Awajún populations, and insects still represent an important part of the indigenous food system. This ethnobiological survey discovered five species that are newly recorded as edible insects. Chemical composition of insects deemed edible by the Awajún ought to be analyzed in the future and awareness about their nutritional importance should be raised to harness the potential of this underutilized yet nutrient-rich traditional food.

Egg production and quality responses of adding up to 7.5% defatted black soldier fly larvae meal in a corn-soybean meal diet fed to Shaver White Leghorns from wk 19 to 27 of age

We examined egg production and quality responses of adding up to 7.5% defatted black soldier fly larvae meal (BSFLM) in a corn-soybean meal diet fed to pullets (19 to 27 wk of age). The concentration of CP and crude fat in BSFLM sample was 59.3 and 7.0% DM, respectively. A corn-soybean meal diet was formulated with 0 or 5.0 or 7.5% BSFLM and fed (n = 6) to a total of 108, 19-wk-old Shaver White pullets placed in conventional cages (6 birds/cage). The birds had free access to feed and water. Hen-day egg production (HDEP) and average egg weight were monitored daily and feed intake (FI) weekly. Egg quality parameters were assessed on individual eggs collected on the 5th d of wk 22, 24, and 26 and included individual EW (IEW), albumen height (HU), yolk color (YC), egg shell-breaking strength (SBS) and thickness (ST). A quadratic response (P < 0.02) was observed for HDEP, EW and egg mass. Specifically, birds fed 0 and 7.5% BSFLM diets had similar (P > 0.05) values for these parameters with birds fed 5.0% BSFLM showing lower (P < 0.05) HDEP than 0 or 7.5% BSFLM fed birds. The HDEP was 89.4, 84.8, and 87.8 for 0, 5.0, and 7.5% BSFLM, respectively. Feeding BSFLM linearly (P < 0.01) increased FI and feed conversion ratio (FCR) (FI/egg mass). There was no diet effect (P > 0.05) on IEW and HU, however, BSFLM linearly (P = 0.02) reduced CV of IEW. The IEW was 53.7, 52.3, and 53.0 g for 0, 5.0, and 7.5% BSFLM-fed birds, respectively and corresponding CV values of IEW were 7.9, 5.2, and 5.1%. Feeding BSFLM linearly (P < 0.01) increased YC, SBS, and ST. In conclusion, birds fed 7.5% BSFLM had similar HDEP and egg mass but poor FCR relative to corn-soybean meal diet without BSFLM. The effects of BSFLM on egg quality characteristics warrant further investigations.

Impact of Edible Cricket Consumption on Gut Microbiota in Healthy Adults, a Double-blind, Randomized Crossover Trial

Edible insects are often considered a nutritious, protein-rich, environmentally sustainable alternative to traditional livestock with growing popularity among North American consumers. While the nutrient composition of several insects is characterized, all potential health impacts have not been evaluated. In addition to high protein levels, crickets contain chitin and other fibers that may influence gut health. In this study, we evaluated the effects of consuming 25 grams/day whole cricket powder on gut microbiota composition, while assessing safety and tolerability. Twenty healthy adults participated in this six-week, double-blind, crossover dietary intervention. Participants were randomized into two study arms and consumed either cricket-containing or control breakfast foods for 14 days, followed by a washout period and assignment to the opposite treatment. Blood and stool samples were collected at baseline and after each treatment period to assess liver function and microbiota changes. Results demonstrate cricket consumption is tolerable and non-toxic at the studied dose. Cricket powder supported growth of the probiotic bacterium, Bifidobacterium animalis, which increased 5.7-fold. Cricket consumption was also associated with reduced plasma TNF-α. These data suggest that eating crickets may improve gut health and reduce systemic inflammation; however, more research is needed to understand these effects and underlying mechanisms.

Edible insects - defining knowledge gaps in biological and ethical considerations of entomophagy

While seeking novel food sources to feed the increasing population of the globe, several alternatives have been discussed, including algae, fungi or in vitro meat. The increasingly propagated usage of farmed insects for human nutrition raises issues regarding food safety, consumer information and animal protection. In line with law, insects like any other animals must not be reared or manipulated in a way that inflicts unnecessary pain, distress or harm on them. Currently, there is a great need for research in the area of insect welfare, especially regarding species-specific needs, health, farming systems and humane methods of killing. Recent results from neurophysiological, neuroanatomical and behavioral sciences prompt caution when denying consciousness and therefore the likelihood of presence of pain and suffering or something closely related to it to insects. From an animal protection point of view, these issues should be satisfyingly solved before propagating and establishing intensive husbandry systems for insects as a new type of mini-livestock factory farming.

Changes in the amino acid profiles and free radical scavenging activities of Tenebrio molitor larvae following enzymatic hydrolysis

Tenebrio molitor (T. molitor) larvae provide food at low environmental cost and contribute positively to livelihoods. In this research, we compared the amino acids compositions and antioxidant activities of various extracts of T. molitor to enhance their quality as food. For the comparison, distilled water extracts, enzymatic hydrolysates, and condensed enzymatic hydrolysates of T. molitor larvae were prepared. Their amino acids (AAs) profiles and antioxidant activities, including ferric-reducing antioxidant power, oxygen radical absorption capacity, and DPPH, hydroxyl radical, and hydrogen peroxide radical scavenging properties assay were analyzed. DW extracts had the lowest AAs contents and antioxidant activity compared with enzymatic extracts. Condensed hydrolysates with a combination of alcalase and flavourzyme (C-A+F) exhibited the highest levels of total free AAs (11.1759 g/100 g). C-A+F produced higher total hydrolyzed AAs (32.5292 g/100 g) compared with the other groups. The C-A+F possessed the strongest antioxidant activity. Notably, the antioxidant activities of the hydrolysates and the total hydrolyzed AAs amount were correlated. Taken together, our findings showed that C-A+F was a promising technique for obtaining extracts of T. molitor larvae with antioxidant activity as potential nutritious functional food.

Effect of enzymatic hydrolysis on bioactive properties and allergenicity of cricket (Gryllodes sigillatus) protein

Food-derived bioactive peptides have gained attention for their role in preventing chronic diseases. Edible insects are viable sources of bioactive peptides owing to their high protein content and sustainable production. In this study, whole crickets (Gryllodes sigillatus) were alcalase-hydrolyzed to a degree of hydrolysis (DH) ranging from 15 to 85%. Antioxidant activity, angiotensin converting enzyme (ACE), and dipeptidyl peptidase-4 (DPP-IV)- inhibition of the cricket protein hydrolysates (CPH) were evaluated before and after simulated gastrointestinal digestion (SGD). Antioxidant activity was similar among CPH, whereas ACE and DPP-IV inhibition was greater (p < 0.05) in CPH with 60-85% DH. Bioactivity improved after SGD. CPH allergenicity was evaluated using human shrimp-allergic sera. All sera positively reacted to tropomyosin in the unhydrolyzed cricket and CPH with 15-50% DH, whereas 60-85% DH showed no reactivity. In conclusion, CPH (60-85% DH) had the greatest bioactive potential and lowest reactivity to tropomyosin, compared with other CPH and the unhydrolyzed control.

Sustainable farming of the mealworm Tenebrio molitor for the production of food and feed

The farming of edible insects is an alternative strategy for the production of protein-rich food and feed with a low ecological footprint. The industrial production of insect-derived protein is more cost-effective and energy-efficient than livestock farming or aquaculture. The mealworm Tenebrio molitor is economically among the most important species used for the large-scale conversion of plant biomass into protein. Here, we review the mass rearing of this species and its conversion into food and feed, focusing on challenges such as the contamination of food/feed products with bacteria from the insect gut and the risk of rapidly spreading pathogens and parasites. We propose solutions to prevent the outbreak of infections among farmed insects without reliance on antibiotics. Transgenerational immune priming and probiotic bacteria may provide alternative strategies for sustainable insect farming.

Use of high hydrostatic pressure to inactivate natural contaminating microorganisms and inoculated E. coli O157:H7 on Hermetia illucens larvae

A chemical and microbiological characterization on Hermetia illucens larvae was carried out as well as an inactivation study of natural contaminating microorganisms and inoculated E. coli O157:H7 in black soldier larvae by using High Hydrostatic Pressure (250 to 400 MPa, for 1.5 to 15 min). Hermetia illucens was mainly composed of proteins (46.49%, d.m.) followed by fat (37.88%, d.m.). Larvae had a high contamination load of Total Aerobic Mesophilic bacteria (AMB) (1.58x107 cfu/g) and Enterobacteriaceae (1.15x106cfu/g). The presence of pathogenic microorganism varied: no Listeria spp. were found, but Salmonella (1.15x106 cfu/g) and E. coli (7.08x105 cfu/g) were detected in the larvae extract. High Hydrostatic Pressure (HHP) was effective against natural contaminating yeasts and molds producing more than 5 log cycle reductions at 400 MPa for any of the times considered (2.5 to 7 min), but a low reduction of total microbial load was achieved. The inactivation level of larvae inoculated with E. coli O157:H7 varied. At 400 MPa for 7 min more than 5 log cycle reductions were achieved. Among the three inactivation models studied, the one that best described the inactivation pattern of the cells, according to the Akaike index, was the Biphasic model.

Traditional consumption of and rearing edible insects in Africa, Asia and Europe

The traditional consumption of edible insects is common in one third of the world's population, mostly in Latin America, Africa and Asia. There are over one thousand identified species of insects eaten in some stage of their life cycle; and they play important roles in ensuring food security. The most common way to collect insects are from the wild, which is seasonal with limited availability and has an increasing demand resulting in a disruption to the ecosystem. There is a growing interest shown in rearing insects for commercial purposes, and an industrial scale production will be required to ensure steady supplies. Industrial production will need to take into account the living environment of insects, the nutritional composition of their feed and the overall efficiency of the production system. We provide a short overview on the consumption of and rearing insects in Africa, Asia and Europe. For Africa, a snapshot is given for Nigeria, Ghana, Central African Republic, Kenya and Uganda, while the following countries are reported for Asia: China, Japan, Lao People's Democratic Republic, Thailand and Vietnam. In addition, a list of insect species with the highest potential for food and feed in the European Union is provided with some reference to The Netherlands and Finland. The review concludes that there is need to better understand the rearing and farming procedures that will yield high quality edible insects in Africa, Asia and Europe.

The bacterial biota of laboratory-reared edible mealworms (Tenebrio molitor L.): From feed to frass

Tenebrio molitor represents one of the most popular species used for the large-scale conversion of plant biomass into protein and is characterized by high nutritional value. In the present laboratory study, the bacterial biota characterizing a pilot production chain of fresh T. molitor larvae was investigated. To this end, different batches of fresh mealworm larvae, their feeding substrate (wheatmeal) and frass were analyzed by viable microbial counts, PCR-DGGE and Illumina sequencing. Moreover, the occurrence of Coxiella burnetii, Pseudomonas aeruginosa and Shiga toxin-producing E. coli (STEC) was assessed through qualitative real-time PCR assays. Microbial viable counts highlighted low microbial contamination of the wheatmeal, whereas larvae and frass were characterized by high loads of Enterobacteriaceae, lactic acid bacteria, and several species of mesophilic aerobes. Spore-forming bacteria were detected to a lesser extent in all the samples. The combined molecular approach used to profile the microbiota confirmed the low microbial contamination of wheatmeal and allowed the detection of Enterobacter spp., Erwinia spp., Enterococcus spp. and Lactococcus spp. as dominant genera in both larvae and frass. Moreover, Klebsiella spp., Pantoea spp., and Xenorhabdus spp. were found to be in the minority. Entomoplasmatales (including Spiroplasma spp.) constituted a major fraction of the microbiota of one batch of larvae. From the real-time PCR assays, no sample was positive for either C. burnetii or STEC, whereas P. aeruginosa was detected in one sample of frass. Based on the overall results, two sources of microbial contamination were hypothesized, namely feeding with wheatmeal and vertical transmission of microorganisms from mother to offspring. Since mealworms are expected to be eaten as a whole, the overall outcomes collected in this laboratory study discourage the consumption of fresh mealworm larvae. Moreover, microbial loads and the absence of potential pathogens known to be associated with this insect species should be carefully assessed in order to reduce the minimum risk for consumers, by identifying the most opportune processing methods (e.g., boiling, frying, drying, etc.).

Nutritional quality of different grades of adult male chinese mitten crab, Eriocheir sinensis

This study mainly investigated the composition of adult male Chinese mitten crab (Eriocheir sinensis) from four grades/sizes (Grade I: 200-249 g; Grade II: 175-199 g; Grade III: 150-174 g; Grade IV: ≤ 150 g). The results showed that the grade III crabs had the largest gonadsomatic index (GSI), which was significantly higher than the grade I and grade II crabs, no significant difference was found with the grade IV crab. Significant differences in moisture and total lipid contents were observed among various edible parts from different grades of male Eriocheir sinensis. In particular, grade II crabs had the highest total lipid and dry matter content for hepatopancreas. A balanced amino acids composition and a high essential amino acids score (EAAS) were found in the muscle and gonads of grade III crabs. The levels of poly-unsaturated fatty acids (PUFA), n-3 PUFA, n-6 PUFA and docosahexaenoic acid (DHA) in the hepatopancreas, as well as the contents of PUFA, highly-unsaturated fatty acids (HUFA), n-3 PUFA, arachidonic acid (ARA), and eicosapentaenoic acid (EPA) in the gonads were significantly increased in the grade II crabs. Taken together, it can generally be concluded that adult male Eriocheir sinensis of 150-200 g (Grade II-III) weight have the highest nutritional quality even though they are not the largest crabs.

Potential of Extracted Locusta Migratoria Protein Fractions as Value-Added Ingredients

Although locusts can be sustainably produced and are nutrient rich, the thought of eating them can be hard to swallow for many consumers. This paper aims to investigate the nutritional composition of Locusta migratoria, including the properties of extracted locust protein, contributing to limited literature and product development opportunities for industry. Locusts sourced from Dunedin, New Zealand, contained a high amount of protein (50.79% dry weight) and fat (34.93%), which contained high amounts of omega-3 (15.64%), creating a desirably low omega-3/omega-6 ratio of 0.57. Three protein fractions including; insoluble locust fraction, soluble locust fraction, and a supernatant fraction were recovered following alkali isoelectric precipitation methodology. Initially, proteins were solubilised at pH 10 then precipitated out at the isoelectric point (pH 4). All fractions had significantly higher protein contents compared with the whole locust. The insoluble protein fraction represented 37.76% of the dry weight of protein recovered and was much lighter in colour and greener compared to other fractions. It also had the highest water and oil holding capacity of 5.17 mL/g and 7.31 mL/g, possibly due to larger particle size. The high supernatant yield (56.60%) and low soluble protein yield (9.83%) was unexpected and could be a result of experimental pH conditions chosen.

Utilization of organic residues using heterotrophic microalgae and insects

Various organic residues occur globally in the form of straw, wood, green biomass, food waste, feces, manure etc. Other utilization strategies apart from anaerobic digestion, composting and incineration are needed to make use of the whole potential of organic residues as sources of various value added compounds. This review compares the cultivation of heterotrophic microalgae and insects using organic residues as nutrient sources and illuminates their potential with regard to biomass production, productivity and yield, and utilization strategies of produced biomasses. Furthermore, cultivation processes as well as advantages and disadvantages of utilization processes are identified and discussed. It was shown that both heterotrophic algae and insects are able to reduce a sufficient amount of organic residues by converting it into biomass. The biomass composition of both organisms is similar which allows similar utilization strategies in food and feed, chemicals and materials productions. Even though insect is the more complex organism, biomass production can be carried out using simple equipment without sterilization and hydrolysis of organic residues. Contrarily, heterotrophic microalgae require a pretreatment of organic residues in form of sterilization and in most cases hydrolysis. Interestingly, the volumetric productivity of insect biomass exceeds the productivity of algal biomass. Despite legal restrictions, it is expected that microalgae and insects will find application as alternative food and feed sources in the future.

Invited review: Resource inputs and land, water and carbon footprints from the production of edible protein of animal origin

Abstract. The objective of this review is to analyze crucial factors in the output from the production of proteins in food of animal origin, such as milk, meat and eggs. We then consider inputs such as land, water, fuel, minerals and feed, as well as characterize emissions. Finally, we estimate footprints for land (land footprint, LF), water (water footprint, WF) and greenhouse gas emissions (i.e., carbon footprint, CF) during the production process. The wide range of different land and water inputs per unit feed between various studies largely influences the results. Further influencing factors are species and categories of animals that produce edible protein, their yields and the feeding of animals. Coproducts with no or low humanly edible fractions and grassland as feed contribute to a lower need for arable land and lower LF, WF and CF. The most efficient land use or the lowest LF per kilogram of edible protein was estimated for higher milk and egg yields; the highest LF values were calculated for beef, followed by pork. The lowest WF and CF were calculated for edible protein of chicken meat and eggs. Edible protein from ruminants is mostly characterized by a higher CF because of the high greenhouse gas potential of methane produced in the rumen. A key prerequisite for further progress in this field is the harmonization of data collection and calculation methods. Alternatives to partial or complete replacement of protein of terrestrial animals, such as marine animals, insects, cell cultures, single-cell proteins or “simulated animal products” from plants, as well as changing eating patterns and reducing food losses are mentioned as further potential ways for more efficient feed production. For all those dealing with plant or animal breeding and cultivation and all those who are working along the whole food production chain, it is a major challenge to enhance the production of more food for more people with, at the same time, less, limited resources and lower emissions.

Moisture adsorption properties and shelf-life estimation of dried and pulverised edible house cricket Acheta domesticus (L.) and black soldier fly larvae Hermetia illucens (L.)

Edible insects are part of the diets of a significant proportion of rural populations in the tropics especially Africa and Asia, and their use as source of key nutrients for better nutrition is re-emerging. Indigenously, elemental methods are used to process the insects before they are consumed or sold in retail outlets. In recent years, better knowledge of processing, packaging and storage has become necessary because of commercialisation needs. A common processing approach involves drying after a brief heat-treatment step, and then milling into a powdered product which is sold to manufacturers or consumers as ingredient for processing final products. The hydration properties of dried powders of edible house cricket and black soldier fly larvae (BSFL) were studied with the aim of predicting shelf-life stability under typical packaging and storage temperatures experienced in the tropics. Moisture adsorption isotherms were determined gravimetrically at 25, 30 and 35 °C, over 0.11-0.97 water activity (a_W) range, and the data fitted to various models. Sorption isotherms were of type II according to Brunauer classification indicating monolayer-multilayer sorption behaviour. Cricket powder exhibited higher hydration capacity, and a_W of this product was less sensitive to temperature variation as compared to BSFL powder. In the two products, water exhibited transitions from bound- to free- state at ~5 g/100 g moisture content. Based on Heiss-Eichner model, a shelf-life of 7 months at 25 °C can be achieved if the cricket and BSFL powders are dried to ca. 5 g/100 g moisture content and packaged in 80 μm thick polyethylene films. At 35 °C the shelf-life of the cricket product is shortened three- to four-fold whereas the BSFL powder is unable to store.

Recovery of soluble proteins from migratory locust (Locusta migratoria) and characterisation of their compositional and techno-functional properties

Edible insects emerged as an alternative source of high-quality proteins. Therefore, the effect of an extraction procedure for the recovery of migratory locust (Locusta migratoria) protein concentrate (MLPC) on the compositional characteristics and techno-functional properties was studied. The influence of pH value (2-10) and salt concentration (0, 1 and 3% w/v) on techno-functional properties was evaluated. Proteins were identified and characterized by RP-HPLC, SDS-PAGE and LC-MS/MS. The initial crude protein content of the whole locusts (65.9% on dry base) could be enhanced to 82.3% (MLPC). Solubility profiles of MLPC showed maximum solubility at pH9 (100%). Promising functionality comparable to egg white protein in terms of emulsifying activity at pH5, foamability at pH3 and 3% NaCl, and foam stability at pH9 were found. Consequently, MLPC offers a nutritious protein source with good functional properties at certain conditions, which could be used as food ingredient in a variety of food systems.

Assessment of Vegetable and Fruit Substrates as Potential Rearing Media for Hermetia illucens (Diptera: Stratiomyidae) Larvae

Hermetia illucens (L.) (Diptera: Stratiomyidae) is able to consume a wide range of organic matter and is of particular interest for waste management. The nutritional value of preimaginal stages, in particular the protein content, makes this species a valid candidate for use as feed for other organisms. Vegetables and fruits are promising rearing substrates for insects produced for this purpose according to the EU regulation. In order to examine the effects of diets on insect performance and chemical composition, larvae were reared on the following substrates: 1) fruit (apple, pear, and orange); 2) vegetable (lettuce, green beans, and cabbage); and 3) mixed fruits and vegetables. High percentages of survival were observed on all diets, but there were differences among weights of larvae, pupae, and adults, with weights of larvae reared on mixed fruits and vegetables lower than on other diets. Pupae reared on the mixed diet were heaviest, and also morphometric measurements of adults were highest. Larvae reared on fruit diets had the highest fat content, comprising mostly saturated fatty acids; the highest content of essential n-3 fatty acids was found in vegetable reared larvae and that of n-6 in mixed reared larvae. Larvae reared on the mixed diet had the highest protein content. Calcium contents were high and moderate amounts of iron and zinc were found. H. illucens showed the capability to develop on vegetable and fruits diets displaying different nutrient profiles and biological performances. The best-performing rearing strategy should vary in relation to the final use of H. illucens.