Mycotoxins in dairy products

Certain fungi produce chemical substances that cause toxic symptoms when food containing them is ingested by man or animals. These compounds are referred to as mycotoxins. Mycotoxins may contaminate dairy products by moulds growing on them, or by the carry-over of mycotoxins occurring in animal feedstuffs ingested by dairy cattle. An example of the first mentioned category is sterigmatocystin, a carcinogenic mycotoxin sometimes occurring on hard cheese. An example of the second category is aflatoxin M₁, a compound strongly suspected to be carcinogenic, which often occurs in milk. Due to the fact that processing of milk does not decrease the aflatoxin M₁ content, aflatoxin M₁ occurs in various dairy products. Sensitive methods of analysis for the determination of mycotoxins in dairy products have been developed in the last 10 years, most of them are based on TLC- or HPLC-separation procedures, followed by fluorimetric measurement.The most fundamental way to tackle the problem of mycotoxin contamination of dairy products is to prevent fungal growth on the dairy products or, in the case of carry-over of mycotoxins, in the crop before, during and after harvest. If measures to prevent fungal growth and mycotoxins production are not taken or fail, one can sometimes resort to physical or chemical methods to eliminate mycotoxins.     

Natural Occurrence of Mycotoxins in Food and Feed: Pakistan Perspective

Fungi are commonly present in the environment and can grow under favorable conditions on an extensive variety of substrates. During harvesting, handling, storage, and distribution, agricultural commodities are subjected to infection by toxigenic molds, which may cause spoilage and produce toxic metabolites called mycotoxins. Fungal contamination of various food commodities with consequent exposure of the community to mycotoxins is a hazard that may exist depending on environmental factors, crop health, and soil conditions. Mycotoxins represent serious consequences due to substantial economic loss and risk to health. The environmental conditions of Pakistan with its mostly warm temperature are conducive to growth of toxigenic fungi resulting in mycotoxin production in different food items. Moreover, the poor conditions of storage and deficiency in regulatory measures in food quality control worsen the situation in the country. This review encompasses mycotoxin contamination of food and feed in Pakistan. High concentrations of mycotoxins are found in some commodities that are used on a daily basis in Pakistan, which may be a concern depending on dietary variety and health conditions of individuals in the population. Therefore, the mycotoxin contamination of foodstuff with exceeding levels represents a serious health hazard for the local population. There is a need to conduct more studies to analyze mycotoxin occurrence in all types of food commodities throughout the country. For consumer safety and the country's economy, the regulatory authorities should take into account this issue of contamination, and control strategies should be implemented and the quality control system of food improved.     

食品中黄曲霉毒素B1污染研究进展

农作物（包括玉米、小麦等）在生长、收获和储存的过程中,容易受到产毒真菌及其代谢毒物（霉菌毒 素）的污染;其加工形成的粮、油等食品及被污染饲料饲养所得的畜产品进入食物链后,易引发人类急、慢性中 毒。黄曲霉毒素B1是众多霉菌毒素中较常见且毒性较高的一种,过量摄入具有致癌、致畸形、免疫抑制等毒性效 应。本文综合国内外研究进展,从食品中黄曲霉毒素B1污染发生的来源及影响因素、黄曲霉毒素B1的分子结构与毒 性、致病机理、限量标准、风险评估及防控等方面对食品中黄曲霉毒素B1污染展开综述。     

The Use and Effects of Lactic Acid Bacteria in Malting and Brewing with Their Relationships to Antifungal Activity,Mycotoxins and Gushing: A Review

Several metabolic properties of lactic acid bacteria (LAB) serve special functions, which directly or indirectly have impact on processes such as improved quality and safety and flavour development in the malting and brewing industry. LAB are widely distributed in nature and in spontaneous fermentations, often they are found to be the dominating microflora resulting in both the inhibition of spoilage bacteria and organisms. This review describes the applications of LAB in malting and brewing. Mycotoxins are naturally occurring toxic secondary metabolites of fungi that may be present in cereals. Several of these mycotoxins have been associated with human and animal diseases and are known to survive the brewing process. LAB have been shown to restrict the growth of the most important toxigenic fungi thereby reducing the formation of these harmful toxins. The occurrence of mycotoxins in cereals is discussed and their effect in beer is reviewed. The main features of this review are: (I) LAB starter cultures in malting and brewing (II) production of acid malt; (III) biological acidification of mash and wort in brewing; (IV) bacteriocins produced by LAB in brewing; (V) LAB and anti‐fungal activity; (VI) mycotoxins in cereals.     

Public Health Significance of Molds and Mycotoxins in Fermented Dairy Products

Mold growth on cheese and other fermented dairy products is a common and recurring problem. Potential mycotoxin contamination is serious since some molds can grow and produce mycotoxins at temperatures as low as ?2 to 10°C. Work can be divided into: 1) incidence, types, and mycotoxin-producing potential of molds in fermented dairy products, 2) experimental mycotoxin production on cheese under conditions of storage and aging of cheese, 3) natural occurrence of mycotoxins in commercial samples of cheese, and 4) potential toxicity of Penicillium roqueforti and its significance in blue veined cheeses.Molds most common on cheese and fermented dairy products are Penicillium species. Mycotoxins produced by these organisms are penicillic acid, patulin, ochratoxin A, and citrinin. Percentages of molds in cheese capable of producing some commonly studied mycotoxins ranged from 1.8% to 12.4%. Cheese is an excellent substrate for mold growth but a poor substrate for mycotoxin production. Several natural occurrences of mycotoxins in cheese include small and variable amounts of patulin, penicillic acid, sterigmatocystin (600 µg/kg), penitrem A, and mycophenolic acid. Penicillium roqueforti is capable of producing toxic alkaloids and other compounds. The significance of these substances for human health is unclear.The decision to trim or to discard moldy cheese can be aided by considering the risk versus benefit based on storage history (temperature), extent of mold growth, appearance of mold (color), and size of cheese.     

Mycotoxins in dairy products: A review

Milk and dairy products continue to raise concerns with regard to contamination with mycotoxins, most of which have a likely or confirmed carcinogenic status. Such concerns are more serious for certain cheeses due to their frequent contamination with high concentrations of mycotoxins from various sources, including the milk used as a raw material and moulds found as contaminants or purposely added for ripening. Different control measures have been suggested to prevent the formation or to remove mycotoxins in dairy products once formed therein. However, these methods either provide an insufficient degree of protection or are onerous to implement. This review surveys the main mycotoxins associated with dairy products and discusses their health significance. Attention is drawn to the lack of knowledge on the emerging and masked mycotoxins with relevance to dairy products. Known control measures are discussed from the perspective of their application while presenting their strengths and weaknesses.     

农产品中真菌毒素检测方法研究进展

真菌毒素是由特定真菌在适宜条件下产生的有毒小分子次级代谢产物,农产品在生长、加工和储运过程中均存在被真菌毒素污染的可能性,被真菌毒素污染的农产品会严重危害动物和人类的健康。因此建立精确、高效的真菌毒素检测方法对于农产品中真菌毒素的防控和监测具有重要意义。本文主要介绍了真菌毒素的产生和危害,综述了近5年农产品中真菌毒素检测方法(仪器分析法、免疫学分析方法和光谱分析法)的研究进展,分析了这些检测方法的优缺点,并展望了农产品中真菌毒素在未来的发展趋势,为农产品中真菌毒素检测的相关研究和安全监管提供参考和启发。     

The Extracellular Protease AprX from Pseudomonas and its Spoilage Potential for UHT Milk: A Review

The negative effects of proteases produced by psychrotrophic bacteria on dairy products, especially ultra‐high‐temperature (UHT) milk, are drawing increasing attention worldwide. These proteases are especially problematic, because it is difficult to control psychrotrophic bacteria during cold storage and to inactivate their heat‐resistant proteases during dairy processing. The predominant psychrotrophic species with spoilage potential in raw milk, Pseudomonas, can produce a thermostable extracellular protease, AprX. A comprehensive understanding of AprX on the aspects of its biological properties, regulation, proteolytic potential, and its impact on UHT milk can contribute to finding effective approaches to minimize, detect, and inactivate AprX. AprX also deserves attention as a representative of all extracellular metalloproteases produced by psychrotrophic bacteria in milk. The progress of current research on AprX is summarized in this review, including a view on the gap in current understanding of this enzyme. Reducing the production and activity of AprX has considerable potential for alleviating the problems that arise from the instability of UHT milk during shelf‐life.     

Integrated management of the risks of stored grain spoilage by seedborne fungi and contamination by storage mould mycotoxins – An update

Fungal spoilage of stored grains may occur when activity of water (aw) in cereal grain exceeds a critical limit enabling mould growth. Because it is not feasible to maintain all parts of large grain bulks below this critical moisture limit during prolonged storage time, an infection by seed-borne fungi is not rare in cereal grain stored under humid temperate or hot climates, inducing irreversible qualitative losses. Additionally, some fungal species produce harmful mycotoxins. The most harmful toxigenic species belong to the group of xerophilic species (genera Aspergillus and Penicillium). Because mycotoxin contamination of cereal grain is a worldwide issue for public health and a permanent concern for cereal-food industries facing the challenge of a permanent monitoring mycotoxin content in their primary matters, tolerable levels of mycotoxins are severely regulated worldwide. Mycotoxin-producing species growth is closely dependent of grain moisture levels enabling biological activity in grain ecosystem. Consequently, mould growth in stored grain bulks can be anticipated through early detection of grain and mould respiration. The prevention of mycotoxigenic fungi spoilage of stored grain can be managed by a preventive strategy. The main objective of the review was to describe the different methods, material and practices combined in such an integrated preventive approach. Some solutions potentially acceptable for the decontamination of moderately contaminated grain are also discussed.Integrated management of mould spoilage risks in stored grain is based on five pillars: i/Prevention of mould development by keeping grain moisture below the critical limit of fungal growth; ii/Accurate monitoring of grain aw and temperature changes during the storage period, associated to the monitoring of early indicators of respiration activity of storage fungi; iii/Reduction of grain bulk moistening trends by physical intervention means; iv/Use of physical treatments (ozone, grain peeling or abrasion) to limit mycotoxin contamination transfer to processed cereal products; v/Possible use of bio-competitive strains of fungi or bacteria to prevent the development of mycotoxigenic fungi in grain bulks. The future research needs on this topic are also evocated.     

Current Immunoassay Methods for the Rapid Detection of Aflatoxin in Milk and Dairy Products

The presence of mycotoxins in foodstuff causes serious health problems to consumers and economically affects the food industry. Among the mycotoxins, aflatoxins are very toxic and highly carcinogenic contaminants which affect the safety of many foods, and therefore endanger human health. Aflatoxin M₁ (AFM₁) found in milk results from the biotransformation of aflatoxin B₁. Many efforts have been made to control the source of AFM₁ from farmers to dairy product companies. However, AFM₁ escapes ordinary methods of food treatment such as cooking, sterilization, and freezing, hence it appears in milk and dairy products. The presence of high levels of AFM₁ constitutes an alarming threat as milk and dairy products contain essential nutrients for human health, especially for infants and children. For this reason, there is a pressing need for developing a fast and reliable screening method for detecting trace aflatoxins in food. Several analytical methods based on high‐performance liquid chromatography (HPLC) and mass spectroscopy have been used for aflatoxin detection; however, they are expensive, time‐consuming, and require many skills. Recently, immunoassay methods, including enzyme‐linked immunosorbent assay (ELISA), immunosensors, and lateral flow immunoassay (LFIA), have been preferred for food analysis because of their improved qualities such as high sensitivity, simplicity, and capability of onsite monitoring. This paper reviews the new developments and applications of immunoassays for the rapid detection of AFM₁ in milk.     

小麦产毒病原菌及其毒素防控的研究进展

小麦是全球第二大粮食作物,每年因病害造成小麦严重减产,品质下降。一些病原菌还能够产生真菌毒素,进一步危害小麦及其制品的质量安全,对人畜健康造成巨大危害。由镰刀菌引起的小麦赤霉病是我国最主要的小麦病害之一,由交链孢引起的小麦黑胚病也备受关注。这2种真菌既能引起小麦病害,又能产生真菌毒素,故称之为产毒病害。镰刀菌产生的脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)、玉米赤霉烯酮(zearalenone,ZEN)、伏马菌素等和交链孢产生的交链孢酚(alternariol,AOH)、交链孢酚单甲醚(alternariol monomethyl ether,AME)和细交链格孢酮酸(tenuazonic acid,Te A)等是2类病原菌产生的主要真菌毒素。本文综述了能引起小麦产毒病害的镰刀菌和交链孢的特点、真菌毒素以及病害和毒素的防控技术,尤其是2类病原菌引起的小麦病害和真菌毒素的防控。这将为后期防治小麦产毒病害及控制毒素产生的研究提供有利参考。     

Recent developments and applications of hyperspectral imaging for rapid detection of mycotoxins and mycotoxigenic fungi in food products

Mycotoxins are the foremost naturally occurring contaminants of food products such as corn, peanuts, tree nuts, and wheat. As the secondary metabolites, mycotoxins are mainly synthesized by many species of the genera Aspergillus, Fusarium and Penicillium, and are considered highly toxic and carcinogenic to humans and animals. Most mycotoxins are detected and quantified by analytical chemistry-based methods. While mycotoxigenic fungi are usually identified and quantified by biological methods. However, these methods are time-consuming, laborious, costly, and inconsistent because of the variability of the grain-sampling process. It is desirable to develop rapid, non-destructive and efficient methods that objectively measure and evaluate mycotoxins and mycotoxigenic fungi in food. In recent years, some spectroscopy-based technologies such as hyperspectral imaging (HSI), Raman spectroscopy, and Fourier transform infrared spectroscopy have been extensively investigated for their potential use as tools for the detection, classification, and sorting of mycotoxins and toxigenic fungal contaminants in food. HSI integrates both spatial and spectral information for every pixel in an image, making it suitable for rapid detection of large quantities of samples and more heterogeneous samples and for in-line sorting in the food industry. In order to track the latest research developments in HSI, this paper gives a brief overview of the theories and fundamentals behind the technology and discusses its applications in the field of rapid detection and sorting of mycotoxins and toxigenic fungi in food products. Additionally, advantages and disadvantages of HSI are compared, and its potential use in commercial applications is reported.     

Occurrence of Aspergillus spp. and aflatoxin B1 in Malaysian foods used for human consumption

Malaysian population widely consumes the cereal-based foods, oilseeds, nuts, and spices in their daily diet. Mycotoxigenic fungi are well known to invade food products under storage conditions and produce mycotoxins that have threat to human and animal health. Therefore, determining toxigenic fungi and aflatoxin B(1) (AFB1) in foods used for human consumption is of prime importance to develop suitable management strategies and to minimize risk. Ninety-five food products marketed in Penang, Malaysia were randomly collected from different supermarkets and were analyzed for presence of Aspergillus spp. by agar plate assay and AFB1 by enzyme-linked immunosorbent assay (ELISA). A. flavus was the dominant fungi in all foods followed by A. niger. Fifty-five A. flavus strains were tested for their ability to produce aflatoxins on rice grain substrate. Thirty-six (65.4%) strains out of 55 produced AFB1 ranging from 1700 to 4400 μg/kg and 17 strains (31%) produced AFB2 ranging from 620 to 1670 μg/kg. Natural occurrence of AFB1 could be detected in 72.6% food products ranging from 0.54 to 15.33 μg/kg with a mean of 1.95 μg/kg. Maximum AFB1 levels were detected in peanut products ranging from 1.47 to 15.33 μg/kg. AFB1 levels detected in all food products were below the Malaysian permissible limits (<35 μg/kg). Aspergillus spp. and AFB1 was not detected in any cookies tested. Although this survey was not comprehensive, it provides valuable information on aflatoxin levels in foods marketed in Malaysia.     

FUSARIUM MOLDS AND THEIR MYCOTOXINS

An overview is presented covering the occurrence of Fusarium species in raw food and feed materials and the mycotoxins produced by these molds. A study of the literature (reported from 1969 until now) revealed the occurrence of over 60 Fusarium species in these raw materials. It appears that the most reported species occur worldwide and in a large variety of raw food products, such as cereals, vegetables and fruits. These Fusarium species occurring in samples are producers of toxigenic secondary metabolites of which more than 100 have been described. Most of them are referred to as mycotoxins of which trichothecencs (e.g., deoxynivalenol, nivalenol, T-2 toxin, diacetoxyscirpenol), fumonisins and zearalenones are most frequently reported .     

Potentially toxigenic fungi from selected grains and grain products

A total of 85 grain and grain product samples (including corn meal, corn muffin mix, popcorn, various types of rice, and self‐rising, all‐purpose unbleached and whole wheat flour) from U.S. retail were tested for fungal contamination levels and profiles using conventional plating as well as molecular methods. The results of this study showed that over 90% of wheat flour and corn product samples and 73% of rice samples tested carried live fungi. Popcorn carried the highest fungal levels reaching 5.45 log₁₀ colony forming units (cfu) per gram followed by corn meal (reaching 5.38 log₁₀ cfu/g). Mold and yeast counts in rice and wheat flour reached 3.30 log₁₀ and 3.28 log₁₀ cfu/g, respectively. The predominant molds in wheat flour were aspergilli and fusaria found in 50 and 46% of samples, respectively; Fusarium spp. were the most frequent contaminants of corn‐based products found in 74% of the samples followed by penicillia (present in 44% of tested samples). Rice, conversely, contained mainly Aspergillus, Fusarium, and yeasts (each found in 21% of the samples).

Practical applications

Toxigenic molds are often contaminating stored grains and grain products and under improper storage conditions could cause spoilage of these commodities accompanied with production of toxic secondary metabolites, mycotoxins. Mycotoxins are known to cause illnesses in humans and animals. Therefore, monitoring the presence and inhibiting the growth of these organisms is critical for achieving and maintaining high quality products, suitable for human and animal consumption, and free of health hazards. Establishing toxigenic mold profiles in stored grains and their derivatives can point to correct storage management and thus reduction/elimination of spoilage and mycotoxin production in these products. In this study we tested several corn, rice, and wheat flour commodities for live potentially toxigenic fungal species. Our findings can help select proper storage management techniques for these commodities.     

Production and stability of patulin, ochratoxin A, citrinin, and cyclopiazonic acid on dry cured ham

Toxinogenic fungal species can be isolated from dry cured meat products, raising the problem of the direct contamination of these foods by mycotoxins known to be carcinogenic or potent carcinogens. Because the contamination of a food by mycotoxins can be considered a balance between production and degradation, the stability of mycotoxins on dry cured meat was also investigated. This study focused on patulin, ochratoxin A, citrinin, and cyclopiazonic acid that can be produced by fungal species previously isolated from dry cured meat products sold on the French market. We demonstrated that neither patulin nor ochratoxin A was produced on dry meat by toxigenic strains, whereas relatively high amounts of citrinin and cyclopiazonic acid were found after a 16-day incubation period at 20 degrees C (87 and 50 mg/kg, respectively). After direct contamination, the initial content of patulin rapidly decreased to become undetectable after only 6 h of incubation at 20 degrees C. For both citrinin and ochratoxin A, the kinetics of decrease at 20 degrees C was less rapid, and the two toxins presented half-lives of 6 and 120 h, respectively. By contrast, more than 80% of the initial contamination in cyclopiazonic acid was still found on ham after a 192-h incubation period. Toxin stability was not affected by storage at 4 degrees C. These results suggest that growth of toxigenic strains of Penicillium has to be avoided on dry meat products.     

国内外水果真菌毒素的限量及检测方法标准分析

水果在采收、运输和贮藏过程中易受到病原微生物污染,产生并积累各种真菌毒素。由于不适宜的加工工艺,这些真菌毒素会迁移至水果加工制品中,进而引起潜在风险。鉴于此,世界各国都积极制定各种标准、法规来控制真菌毒素在水果及其制品中的污染水平。本文综述了近年来我国水果中真菌毒素的现行限量标准及检测方法标准的制修订状况,并与国外相应的标准进行了对比和探讨,分析了在我国建立水果中真菌毒素限量及检测方法标准的紧迫性和重要性,以期为相关检测人员进行水果中真菌毒素检测时选择方法提供依据,同时也为政府部门制定国家标准提供参考。     

Predicting mycotoxins in foods: A review

The need to ensure the microbiological quality and safety of food products has stimulated interest in the use of mathematical models for quantifying and predicting microbial behaviour. For 20 years, predictive microbiology has been developed for predicting the occurrence of food-borne pathogens, although these tools are dedicated to bacteria. Recently, the situation has changed and a growing number of studies are available in the literature dealing with the predictive modelling approach of fungi. To our knowledge the present one is the first review focussed on predictive mycology and food safety, including mycotoxins; existing kinetic and probability models applied to mycotoxigenic fungi germination and growth, and mycotoxin production are reviewed.     

Mycobiota of cocoa: from farm to chocolate

The present work was carried out to study the mycobiota of cocoa beans from farm to chocolate. Four hundred and ninety-four samples were analyzed at various stages of cocoa processing: (i) primary stage at the farm (fermentation, drying, and storage), (ii) secondary stage at processing (testa, nibs, liquor, butter, cake and powder) and (iii) the final chocolate product (dark, milk, white and powdered) collected from retail outlets. Direct plating or dilution plating on Dichloran 18% Glycerol agar were used for cocoa beans and processed product analyses, respectively. Fungi were isolated and identified using different keys of identification. The largest numbers and diversity of fungi were observed in the samples collected at the farm, especially during drying and storage. The species with the highest occurrence among samples were: Absidia corymbifera, Aspergillus sp. nov., A. flavus, Penicillium paneum and yeasts. A total of 1132 potentially toxigenic fungi were isolated from the following species or species groups: A. flavus, Aspergillus parasiticus, Aspergillus nomius, Aspergillus niger group, Aspergillus carbonarius and Aspergillus ochraceus group. The highest percentage of toxigenic fungi was found at the drying and storage stages. The industrial processing reduced the fungal contamination in all fractions and no fungi were found in the final chocolate products. The knowledge of which fungi are dominant at each processing stage of cocoa provides important data about their ecology. This understanding leads to a reduction in fungal spoilage and mycotoxin production in this product.     

超高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速测定乳及乳制品中21种真菌毒素

建立利用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱联用技术同时测定乳及乳制品中21种真菌毒素的方法.乳及乳制品经酸化乙腈提取后,采用Captiva-EMR Lipid净化柱净化,以C18色谱柱进行色谱分离,质谱采用全扫描/数据依赖的二级扫描模式(full scan data-dependent MS/MS acqu...