Mycotoxins are a potential health threat in cereals including wheat. In the European Union (EU), mycotoxin maximum levels are laid down for cereal raw materials and final food products. For wheat and wheat‐based products, the EU maximum levels apply to deoxynivalenol (DON), zearalenone, aflatoxins, and ochratoxin A. This review provides a comprehensive overview on the different mycotoxins and their legal limits and on how processing of wheat can affect such contaminants, from raw material to highly processed final products, based on relevant scientific studies published in the literature. The potential compliance with EU maximum levels is discussed. Of the four mycotoxins regulated in wheat‐based foods in the EU, most data are available for DON, whereas aflatoxins were rarely studied in the processing of wheat. Furthermore, available data on the effect of processing are outlined for mycotoxins not regulated by EU law—including modified and emerging mycotoxins—and which cover DON derivatives (DON‐3‐glucoside, mono‐acetyl‐DONs, norDONs, deepoxy‐DON), nivalenol, T‐2 and HT‐2 toxins, enniatins, beauvericin, moniliformin, and fumonisins. The processing steps addressed in this review cover primary processing (premilling and milling operations) and secondary processing procedures (such as fermentation and thermal treatments). A special focus is on the production of baked goods, and processing factors for DON in wheat bread production were estimated. For wheat milling products derived from the endosperm and for white bread, compliance with legal requirements seems to be mostly achievable when applying good practices. In the case of wholemeal products, bran‐enriched products, or high‐cereal low‐moisture bakery products, this appears to be challenging and improved technology and/or selection of high‐quality raw materials would be required.

Tortillas are a traditional staple food in Mesoamerican cuisine, which have also become popular on a global level, e.g., for wraps or as snacks (tortilla chips). Traditional tortilla production includes alkaline cooking (nixtamalization) of maize kernels. This article summarizes the current knowledge on mycotoxin changes during the nixtamalization of maize and tortilla production. Upon nixtamalization, mycotoxins can be affected in different ways. On the one hand, the toxins can be physically removed during steeping and washing. On the other hand, mycotoxins might be degraded, modified, or released/bound in the matrix by high pH and/or high temperature. This also applies to the subsequent baking of tortillas. Many studies have shown reduced mycotoxin levels in alkali-cooked maize and in tortillas. Most of the available data relate to aflatoxins and fumonisins. The reduction (and detoxification) of aflatoxins during nixtamalization might, however, be partially reversed in acidic conditions. The loss of fumonisin concentrations is to some extent accompanied by hydrolyzation and by lower toxicity. However, some studies have indicated the potential formation of toxicologically relevant modified forms and matrix-associated fumonisins. More data are required to assess the influence of alkaline cooking regarding such modified forms, as well as mycotoxins other than aflatoxins/fumonisins.

Mycotoxins are naturally occurring fungal metabolites that are associated with health hazards and are widespread in cereals including maize. The most common mycotoxins in maize that occur at relatively high levels are fumonisins (FBs), zearalenone, and aflatoxins; furthermore, other mycotoxins such as deoxynivalenol and ochratoxin A are frequently present in maize. For these toxins, maximum levels are laid down in the European Union (EU) for maize raw materials and maize‐based foods. The current review article gives a comprehensive overview on the different mycotoxins (including mycotoxins not regulated by EU law) and their fate during secondary processing of maize, based on the data published in the scientific literature. Furthermore, potential compliance with the EU maximum levels is discussed where appropriate. In general, secondary processing can impact mycotoxins in various ways. Besides changes in mycotoxin levels due to fractionation, dilution, and/or concentration, mycotoxins can be affected in their chemical structure (causing degradation or modification) or be released from or bound to matrix components. In the current review, a special focus is set on the effect on mycotoxins caused by different heat treatments, namely, baking, roasting, frying, (pressure) cooking, and extrusion cooking. Production processes involving multiple heat treatments are exemplified with the cornflakes production. For that, potential compliance with FB maximum levels was assessed. Moreover, effects of fermentation of maize matrices and production of maize germ oil are covered by this review.

Mycotoxins are naturally present in cereal-based feed materials; however, due to adverse effects on animal health, their presence in derived animal feed should be minimized. A systematic literature search was conducted to obtain an overview of all factors from harvest onwards influencing the presence and concentration of mycotoxins in cereal-based feeds. The feed production processes covered included the harvest time, post-harvest practices (drying, cleaning, storage), and processing (milling, mixing with mycotoxin binders, extrusion cooking, ensiling). Delayed harvest supports the production of multiple mycotoxins. The way feed materials are dried after harvest influences the concentration of mycotoxins therein. Applying fungicides on the feed materials after harvest as well as cleaning and sorting can lower the concentration of mycotoxins. During milling, mycotoxins might be redistributed in cereal feed materials and fractions thereof. It is important to know which parts of the cereals are used for feed production and whether or not mycotoxins predominantly accumulate in these fractions. For feed production, mostly the milling fractions with outer parts of cereals, such as bran and shorts, are used, in which mycotoxins concentrate during processing. Wet-milling of grains can lower the mycotoxin content in these parts of the grain. However, this is typically accompanied by translocation of mycotoxins to the liquid fractions, which might be added to by-products used as feed. Mycotoxin binders can be added during mixing of feed materials. Although binders do not remove mycotoxins from the feed, the mycotoxins become less bioavailable to the animal and, in the case of food-producing animals, to the consumer, lowering the adverse effects of mycotoxins. The effect of extruding cereal feed materials is dependent on several factors, but in principle, mycotoxin contents are decreased after extrusion cooking. The results on ensiling are not uniform; however, most of the data show that mycotoxin production is supported during ensiling when oxygen can enter this process. Overall, the results of the literature review suggest that factors preventing mycotoxin production have greater impact than factors lowering the mycotoxin contents already present in feed materials.

Staphylococcus aureus is an important opportunistic pathogen of both humans and animals. It can cause several diseases, including mastitis, as well as food poisoning by production of heat-stable enterotoxins in food. The aim of this study was to determine the prevalence of S. aureus and the diversity of strains circulating in the Zambian dairy value chain, which have not been studied in detail before. Three provinces were covered by the study (Lusaka, Southern, and Western) and almost 2000 samples along the dairy value chain, covering both the informal and formal market sectors, were taken at two time points (dry and wet season), with a special focus on raw milk. Nearly 300 presumptive S. aureus isolates were confirmed by MALDI-TOF MS and real-time PCR. Raw milk from traditional and smallholder farms was widely contaminated with S. aureus; prevalence was 33-46% depending on the study province. Raw milk from milk collection centres, informal traders, traditional market sellers, and processors were also frequently contaminated with S. aureus. In addition, S. aureus was detected in several milk bucket swabs and nasal and hand swabs of milkers. From industrially processed (heat-treated) milk and dairy products, no S. aureus was isolated. Methicillin-resistant S. aureus (MRSA) were not detected, but around 10% of the S. aureus isolates carried lukS-PV, a marker gene for the virulence factor Pantone-Valentine leucocidin (PVL), which has been associated with severe diseases in human. Molecular typing identified a total of 44 spa types including 13 novel types: t18396, t18397, t18398, t18399, t18400, t18402, t18416, t20459, t20460, t20461, t20462, t20463, and t20464. Furthermore, 12 novel multi-locus sequence types were identified: ST7012, ST7100, ST7101, ST7177, ST7291, ST7304, ST7305, ST7344, ST7596, ST7597, ST7598, and ST7599, of which ST7012, ST7177, and ST7596 fall into the bovine-associated clonal linage CC97. The spa types t084, t267, t355, and the novel type t20464 were common in all three study provinces. The predominant spa type varied depending on the province. Whole genome sequencing (WGS) and core genome multi-locus sequence typing (cgMLST) indicates transmission of strains along the Zambian dairy chain with possible persistence in the chain over time. cgMLST also revealed a very close relatedness between some isolates from milkers and from raw milk or milk buckets. The high prevalence and wide spa type diversity of S. aureus, as well as possible direct or indirect transmission of (potentially highly virulent) S. aureus to humans along the Zambian dairy value chain, are of public health concern, particularly as milk and milk products are often consumed raw by the Zambian population.