Co-Contamination of Food and Feed with Mycotoxin and Bacteria and Possible Implications for Health

Food and feed safety is an issue of great concern for both animal and human health, due to the frequent contamination of food and feed with pathogens, such as bacteria, viruses, yeasts, molds, and parasites. The present paper assumes the possibility that a mycotoxin contamination could occur at the same time as a bacterial infection and investigates the effects of such co-contamination, in comparison with the individual effects of bacterial challenge. For this purpose, we have investigated the effects of simultaneous contamination of swine peripheral blood mononuclear cells (PBMCs) with lipopolysaccharide (LPS) (as a model for bacterial contamination) and mycotoxins (ochratoxin or zearalenone) on cell viability, cell cycles, oxydative stress, and inflammation. Our results show important additive/synergistic effects of co-exposure to fungal and bacterial toxins, and that these effects are more important when the cells are co-exposed to LPS and ochratoxin (OTA). The exposure of PBMCs to both OTA and LPS induced an exacerbation of the increase in the inflammation of concentrations of pro-inflamatory cytokines, compared with that of LPS-challenged cells: IL-1β (4.1 times increase), TNF-α (3.2 times increase), IL-6 (3.1 times increase). There was also a decrease in antioxidant defence (i.e., a significant decrease in the total antioxidant capacity and catalase activity) and a significant increase in the percentage of cells undergoing necrosis (24.3% vs. 15.3% in LPS-treated cells). The exposure to zearalenone (ZEA) and LPS led to less important effects and concerned mainly the parameters related to oxidative stress (i.e., a decrease in total antioxidant capacity). The present study provides important data for risk assessment, as the concomitant contamination with bacteria and mycotoxins can lead to a higher toxicity than that which results after an individual infection with Gram-negative bacteria.