Detection of selected heavy metals and micronutrients in edible insect and their dependency on the feed using XRF spectrometry

Abstract

Edible insect can be a valuable source of nutrients, but also a potential source of heavy metals. Quick detection of overlimit heavy metals concentration could be a key to processing and quick distribution of edible insect products. The aim of this work was to evaluate the feed-dependent content of heavy metals in the mealworm and superworm using the X-ray fluorescence spectrometry as an easy, cheap and a timeless screening method for evaluating the content of heavy metals and microelements. Using a handheld analyser the content of Cd, Pb, Cu and Zn were detected. Both analysed species proved dependency of metal content on a feed. Detected level of Cu in mealworm was between 571 mg.kg -1 and 1768 mg.kg -1 and in superworm from 571 mg.kg -1 to 1768 mg.kg -1 based on the feed. The content of Zn was similar, between 725 mg.kg -1 and 1437 mg.kg -1 in mealworm and 555-1482 mg.kg -1 in superworm. The level of Pb was below the detection limit in all samples, thus from this point of view this food seems to be safe. On the contrary, the content of Cd in the dry matter samples was above the food limit -147 mg.kg -1 to 230 mg.kg -1 . From this point of view, the samples were evaluated as unsuitable for consuming.

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

“…For instance, feed ingredients such as wheat, rice, mussels, and animal kidney corns were shown to contain a high level of cadmium [102]. Mlček et al [103] reported that the accumulated heavy metal content is dependent on the feed and that the level of Pb in T. molitor larvae was below the detection limit, but the content of Cd in the dry matter of T. molitor larvae (147 to 230 mg/kg) was above the food limit. The accumulation of heavy metals in insects may be toxic to animals and humans.…”

Insect as feed ingredients for pigs

“…In addition, it is necessary to verify the functional effects of insect products (e.g., chitin, bioactive compounds; [ 15 , 49 ]) that can be expected when used in swine diets. Furthermore, there are potential safety issues of insect products for toxic substances [ 50 ], antibiotic resistance gene [ 51 ], contamination by pathogens or mycotoxins [ 52 , 53 ], and heavy metal accumulation [ 54 ].…”

Minerals in edible insects: review of content and potential for sustainable sourcing

“…The levels of selected elements in insects are dependent on food source, species and breeding environment. For example, the content of Cu and Zn in T. molitor was higher when fed with wheat bran than oat bran [13,28]. After eating feed containing Ni, Zn and Pb, the increased heavy metal content in the Spodoptera litura midgut, fat body, epidermis and hemolymph correlated with rising heavy metal concentrations in feed.…”

“…Edible insects are rich in nutritional value and are a potential source of minerals such as Cu, Fe, Mg, Mn, P, Se and Zn [28][29]. The extent of mineral accumulation varies with the element, the species, and the growth phase of the insect [21]; consequently, it is critical to understand the accumulation of essential minerals in edible insects to better utilize them in large-scale industrial production.…”