Edible insects have emerged as an alternative and sustainable source of high-quality, animal-derived protein and fat for livestock production or direct human nutrition. During the production of insects, substrate quality is a key parameter to assure optimal insect biomass gain as well as the safety of feed and food derived from commercially reared insects. Therefore, the influence of a realistic substrate contamination scenario on growth performance and accumulation behaviour of black soldier fly larvae (BSFL; Hermetia illucens L.) was investigated. Newly hatched larvae were fed on a corn-based substrate spiked with heavy metals (As, Cd, Cr, Hg, Ni, Pb), mycotoxins (aflatoxins B1/B2/G2, deoxynivalenol, ochratoxin A, zearalenone) and pesticides (chlorpyrifos, chlorpyrifos-methyl, pirimiphos-methyl) under defined breeding conditions (10 days, 28°C, 67% relative humidity). The extent of contaminants' bioaccumulation in the larval tissue as well as the effect on growing determinants were examined. The applied heavy metal substrate contamination was shown to impair larval growing indicated by significantly lower post-trial larval mass and feed conversion ratio (FCR). Cd and Pb accumulation factors of 9 and 2, respectively, were determined, while the concentrations of other heavy metals in the larvae remained below the initial substrate concentration. In contrast, mycotoxins and pesticides have neither been accumulated in the larval tissue nor significantly affected the growing determinants in comparison with the control. The use of BSFL as livestock feed requires contaminant monitoring - especially for Cd and Pb - in the substrates as well as in feedstuff containing BSFL to ensure feed and food safety along the value chain.

Since June 2013 the total feed ban of processed animal proteins (PAPs) was partially lifted. Now it is possible to mix fish feed with PAPs from non-ruminants (pig and poultry). To guarantee that fish feed, which contains non-ruminant PAPs, is free of ruminant PAPs, it has to be analysed with a ruminant PCR assay to comply with the total ban of feeding PAPs from ruminants. However, PCR analysis cannot distinguish between ruminant DNA, which originates from proteins such as muscle and bones, and ruminant DNA, which comes from feed materials of animal origin such as milk products or fat. Thus, there is the risk of obtaining positive ruminant PCR signals based on these materials. The paper describes the development of the combination of two analysis methods, micro-dissection and PCR, to eliminate the problem of 'false-positive' PCR signals. With micro-dissection, single particles can be isolated and subsequently analysed with PCR.

Salmonella can enter animal stocks via feedstuffs, thus posing not only an infection risk for animals, but also threatening to contaminate food of animal origin and finally humans. Salmonella contamination in feedstuffs is still a recurring and serious issue in animal production (especially for the poultry sector), and is regularly detected upon self-monitoring by feed companies (self-checks) and official inspections authorities. Operators within the feed chain in certain cases need to use hygienic condition enhancers, such as organic acids, to improve the quality of feed for animal nutrition, providing additional guarantees for the protection of animal and public health. The present study investigated the efficiencies of five organic acid preparations. The acid products were added to three different feed materials contaminated with Salmonella (contamination occurred by recontamination in the course of the production process) at seven different inclusion rates (1-7%) and analysed after 1, 2, and 7 days' exposure time using culture method (tenfold analysis). A reliable standard was established for defining a successful decontamination under the prevailing test conditions: 10 Salmonella-negative results out of 10 tested samples (0/10: i.e. 0 positive samples and 10 negative samples). The results demonstrated that the tested preparations showed significant differences with regard to the reduction in Salmonella contamination. At an inclusion rate of 7% of the feed materials, two out of five acid preparations showed an insufficient, very small, decontamination effect, whereas two others had a relatively large partial effect. Reliable decontamination was demonstrated only for one acid preparation, however, subject to the use of the highest acid concentration.

The aim of this study was to investigate the effects of garlic oil, cinnamaldehyde, carvacrol, thymol, and thyme oil on growth and biofilm formation of Escherichia coli and Salmonella serotypes, including field isolates from livestock animals. Minimum inhibitory concentrations (MIC) were determined using broth micro-dilution method. Biofilm biomass was assessed by measuring the attached biomass with microtiter plate assay and crystal violet (CV) staining. The strongest antimicrobial effects on E. coli serotypes were observed for thymol at 150 ppm, followed by carvacrol and cinnamaldehyde at 300 ppm and thyme oil at 600 ppm. Similar results were obtained with Salmonella serotypes except for carvacrol (MIC value at 150 ppm). Garlic oil showed no growth inhibition on serotypes of E. coli and Salmonella up to 10000 ppm. Cinnamaldehyde proved to be the most effective substance in reducing E. coli CV-biofilm formation at sub-MIC level with a threshold concentration of 5 ppm, followed by carvacrol, thymol, and thyme oil at 40 ppm and garlic oil at 10000 ppm. CV-biofilm formation of Salmonella serotypes at sub-MIC level was clearly reduced with 40 ppm cinnamaldehyde and 80 ppm carvacrol, thymol, and thyme oil. No reduction of CV-biofilm formation was observed with garlic oil. The present study demonstrates a strong antibacterial activity of cinnamaldehyde, carvacrol, thymol, and thyme oil. Similar response of field isolates and type strains to these phytogenics suggests a general effect within the bacterial species tested. All four substances were also able to reduce CV-biofilm formation at sub-MIC level. Investigating phytogenics with bacterial field isolates contributes to the development of feed additives as alternatives to antibiotics in animal feed to increase productivity and animal welfare in modern livestock production.