Purpose: Consumer confidence in the European food industry has been shaken by a number of recent scandals due to food fraud and accidental contamination, reminding the authors that deliberate incidents can occur. Food defence methods aim to prevent or mitigate deliberate attacks on the food supply chain but are not a legal requirement. The purpose of this paper is to discuss how proactive and reactive food defence practices can help prevent or mitigate malicious attacks on the food chain and also food fraud, food crime and food safety. The authors look at how food defence differs from food safety and how it contributes to food supply chain integrity. Design/methodology/approach: Food defence has been the focus of two different EU FP7 security projects, EDEN and SNIFFER. Food industry stakeholders participated in workshops and demonstrations on food defence and relevant technology was tested in different food production scenarios. Findings: Food industry end-users reported a lack of knowledge regarding food defence practices. They wished for further guidelines and training on risk assessment as well as access to validated test methods. Novel detection tools and methods showed promise with authentication, identification, measurement, assessment and control at multiple levels of the food supply chain prior to distribution and retail. Practical implications: The prevention of a contamination incident, prior to retail, costs less than dealing with a large foodborne disease outbreak. Food defence should therefore be integral to food supply chain integrity and not just an afterthought in the wake of an incident. Originality/value: It is argued that food defence practices have a vital role to play across the board in unintentional and intentional food contamination incidents. The application of these methods can help ensure food supply chain integrity.

Leishmaniasis is a parasitic disease caused by different species of Leishmania and transmitted through the bite of sand flies vector. Macrophages (MΦ), the target cells of Leishmania parasites, are phagocytes that play a crucial role in the innate immune microbial defense and are antigen-presenting cells driving the activation of the acquired immune response. Exploring parasite–host communication may be key in restraining parasite dissemination in the host. Extracellular vesicles (EVs) constitute a group of heterogenous cell-derived membranous structures, naturally produced by all cells and with immunomodulatory potential over target cells. This study examined the immunogenic potential of EVs shed by L. shawi and L. guyanensis in MΦ activation by analyzing the dynamics of major histocompatibility complex (MHC), innate immune receptors, and cytokine generation. L. shawi and L. guyanensis EVs were incorporated by MΦ and modulated innate immune receptors, indicating that EVs cargo can be recognized by MΦ sensors. Moreover, EVs induced MΦ to generate a mix of pro- and anti-inflammatory cytokines and favored the expression of MHCI molecules, suggesting that EVs antigens can be present to T cells, activating the acquired immune response of the host. Since nano-sized vesicles can be used as vehicles of immune mediators or immunomodulatory drugs, parasitic EVs can be exploited by bioengineering approaches for the development of efficient prophylactic or therapeutic tools for leishmaniasis.

Dendritic cells (DCs) capture pathogens and process antigens, playing a crucial role in activating naïve T cells, bridging the gap between innate and acquired immunity. However, little is known about DC activation when facing Leishmania parasites. Thus, this study investigates in vitro activity of canine peripheral blood-derived DCs (moDCs) exposed to L. infantum and L. amazonensis parasites and their extracellular vesicles (EVs). L. infantum increased toll-like receptor 4 gene expression in synergy with nuclear factor κB activation and the generation of pro-inflammatory cytokines. This parasite also induced the expression of class II molecules of major histocompatibility complex (MHC) and upregulated co-stimulatory molecule CD86, which, together with the release of chemokine CXCL16, can attract and help in T lymphocyte activation. In contrast, L. amazonensis induced moDCs to generate a mix of pro- and anti-inflammatory cytokines, indicating that this parasite can establish a different immune relationship with DCs. EVs promoted moDCs to express class I MHC associated with the upregulation of co-stimulatory molecules and the release of CXCL16, suggesting that EVs can modulate moDCs to attract cytotoxic CD8⁺ T cells. Thus, these parasites and their EVs can shape DC activation. A detailed understanding of DC activation may open new avenues for the development of advanced leishmaniasis control strategies.

African trypanosomiasis or sleeping sickness is a zoonotic disease caused by Trypanosoma brucei, a protozoan parasite transmitted by Glossina spp. (tsetse fly). Parasite introduction into mammal hosts triggers a succession of events, involving both innate and adaptive immunity. Macrophages (MΦ) have a key role in innate defence since they are antigen-presenting cells and have a microbicidal function essential for trypanosome clearance. Adaptive immune defence is carried out by lymphocytes, especially by T cells that promote an integrated immune response. Like mammal cells, T. b. brucei parasites release extracellular vesicles (TbEVs), which carry macromolecules that can be transferred to host cells, transmitting biological information able to manipulate cell immune response. However, the exact role of TbEVs in host immune response remains poorly understood. Thus, the current study examined the effect elicited by TbEVs on MΦ and T lymphocytes. A combined approach of microscopy, nanoparticle tracking analysis, multiparametric flow cytometry, colourimetric assays and detailed statistical analyses were used to evaluate the influence of TbEVs in mouse mononuclear cells. It was shown that TbEVs can establish direct communication with cells of innate and adaptative immunity. TbEVs induce the differentiation of both M1- and M2-MΦ and elicit the expansion of MHCI⁺, MHCII⁺ and MHCI⁺MHCII⁺ MΦ subpopulations. In T lymphocytes, TbEVs drive the overexpression of cell-surface CD3 and the nuclear factor FoxP3, which lead to the differentiation of regulatory CD4⁺ and CD8⁺ T cells. Moreover, this study indicates that T. b. brucei and TbEVs seem to display opposite but complementary effects in the host, establishing a balance between parasite growth and controlled immune response, at least during the early phase of infection.

We report the development of new chemical probes for cereulide, a toxic metabolite produced by specific strains of Bacillus cereus, through displacement of potassium cations from a preformed specific complex and a subsequent change in the fluorescence emission. For this purpose, we designed fluorescent probes for potassium cations that were suitable for displacement assays with cereulide from organic extracts. The fluorescence detection of natural cereulide in rice samples was achieved by using synthetic cereulide as a reference and a potassium fluorescent reporter, and this was found to be useful as a portable and fast method for the in situ detection of cereulide in food extracts. To study the fate of cereulide in live cells, we designed a procedure that was suitable for live‐cell microscopy imaging of HeLa cells by comparing the cellular location of the potassium fluorogenic probe, which stained intracellular endolysosomes, in the absence and presence of cereulide; we concluded that in the presence of cereulide, the fluorescence of the probe was decreased because of complexation of the potassium ions by cereulide.