The Impact of Farm and Industrial Feed Waste on the Safety Parameters of Tenebrio molitor Larvae

Abstract

The rising global demand for animal-based food has an increasingly detrimental ecological impact, exacerbated by significant food waste (approximately one-third of all food). This research aimed to analyze the possibility of changing the usually balanced feed with sustainable alternatives that remain as a by-product of the production of farms, grain processing, and breweries, thus promoting the sustainability of agriculture. The mealworm larvae were reared on different substrates: (1) agar-agar gels, wheat bran, and brewer’s yeast, (2) carrots, wheat bran, and brewer’s yeast, (3) sprouted potatoes, wheat bran, and brewer’s yeast, and (4) carrots, brewers’ spent grain and brewer’s yeast. For analysis, the frozen larvae were lyophilized and tested for chemical safety in three accredited laboratories. The results have shown that all tested samples had lower levels of pesticides than the detection limit. In scientific literature, we didn’t find studies on polycyclic aromatic hydrocarbons (PAH). In our study, we found PAH in the substrate and these toxins, as our study shows, can also enter the larvae, but no significant accumulation was observed (sum of benzo(a)pyrene, benz(a)anthracene, benzo(b)fluoranthene and chrysene was 0.0007 mg/kg). Furthermore, the total content of PAH, benzo(a)pyrene and histamine did not exceed recommended levels. We have noticed that the highest concentration of heavy metals (e.g., chromium—1.45 ± 0.02) was found in the sample with the brewer’s by-products. While numerous studies utilize plant-derived by-products, the accumulation of glycoalkaloids has not been explored. Among the all glycoalkaloids (tomatidin, tomatine, α-solanine, α-chaconine and solanidin), amounts of α-solanine and α-chaconine were the highest, detected in the sample with sprouted potatoes (175.12 ± 0.21 and 139.32 ± 0.32 mg/kg, respectively). The amount of total putrescine, tyramine, spermine, and spermidine in mealworm larvae was statistically higher compared to the amount detected in the substrate, and histamine level-on the contrary, was statistically significantly lower compared to the amount detected in the substrate. Considering the amount of toxic substances found in the substrate from the by-products, we can assume that mealworms did not accumulate high levels of toxins, which would violate regulations.

Innovative Applications of Tenebrio molitor Larvae in the Production of Sustainable Meat Sausages: Quality and Safety Aspects

“…In all samples, except for spermine, the content of cadaverine, putrescine, tyramine, and spermidine increased proportionally with the concentration of mealworms (p < 0.05). In a previously published article, we identified notably elevated levels of biogenic amines in mealworm larvae, hypothesizing a potential influence from microorganisms residing within the larvae's bodies [45]. Thus, in summary, it can be concluded that the amount of biogenic amines formed after the introduction of mealworms into sausages increased in all cases, except for spermine, but this does not have a significant impact on the overall safety of sausages.…”

“…Safety Parameters 2.5.1. Biogenic Amines Biogenic amines were determined analogously to Jankauskien ė et al's previously published article [45].…”

Nutritional Composition and Safety Parameters of Mealworms (Tenebrio molitor) Reared on Substrates Derived from By-Products

“…However, regardless of the nutritional value, it is equally important to monitor the formation of chemical toxins that can have a negative impact on human health [20]. Although the majority of chemical toxins, including biogenic amines, polycyclic aromatic hydrocarbons, heavy metals, glycoalkaloids, pesticides, etc., have already been examined and the results were published by the authors, it is necessary to pay attention to peroxides and volatile fatty acids, which have not been studied yet using these by-products [21]. The larvae primarily consume organic materials, which are converted into energy and other substances during digestion [22].…”

“…In this research, we addressed a research gap by investigating the peroxide and volatile fatty acid content of mealworms, which had not been widely examined, and by analyzing potential factors influencing their formation. Additionally, we expanded upon the chemical safety and nutritional value analyses conducted in a previous study [21]. Furthermore, we explored the use of sprouted potatoes as a substrate, which is particularly relevant for our region but has not been tested by other researchers.…”