Production and migration of ochratoxin A and citrinin in Comté cheese by an isolate of Penicillium verrucosum selected among Penicillium spp. mycotoxin producers in YES medium

Mechanism of Mycotoxin Contamination of Medicinal Herbs

Mycotoxin contamination in medicinal plants can lead to toxicity, reduced therapeutic efficacy, and economic losses. This contamination has emerged as a significant issue, drawing attention from researchers and research centers worldwide. Over recent decades, numerous analytical studies have addressed mycotoxin contamination in these herbs, evaluating various methods to determine their presence quantitatively and qualitatively. While several reviews have summarized these studies, they often overlook a comprehensive exploration of the mechanisms and influencing factors of mycotoxin contamination in medicinal herbs. Therefore, this review aims to delve into the mechanisms of aflatoxin and ochratoxin contamination in some of the most widespread medicinal herbs, including jujube fruits, lotus seeds, and licorice roots. The factors influencing these mechanisms were also examined, including the physical composition and maturity stages of the herbs. This review concluded that aflatoxin and ochratoxin A contamination of medicinal herbs involves complex interactions between the herbs' natural defenses, fungal pathogenicity, chemical composition, physical characteristics, and individual plant differences at various maturity stages. Understanding these mechanisms of contamination, and their association with maturity, nutrient profile, and physical development, advances our comprehension of mycotoxin contamination in medicinal herbs.

Mycotoxins in Cheese: Assessing Risks, Fungal Contaminants, and Control Strategies for Food Safety

According to the scientific information reviewed, cheese is highly susceptible to contamination by mycotoxin-producing fungi, primarily species from the genera Aspergillus (A. niger, A. flavus) and Penicillium (P. commune, P. solitum, P. palitans, and P. crustosum). Studies on various types of cheese made from cow's milk report an average concentration of Aflatoxin M1 (AFM1) at 13,000 ng kg-1, which is alarming since the regulatory limits for AFM1 in cheese range from 250 to 500 ng kg-1. For instance, limits set by Codex Alimentarius, the European Commission (EC), Turkey, and Iran are 250 ng kg-1. In the Netherlands, the limit is 200 ng kg-1, and in Italy, it is 450 ng kg-1. However, the concentration of mycotoxins frequently exceeds these regulatory limits, including critical mycotoxins such as ochratoxin A, citrinin, and cyclopiazonic acid, which pose significant global health concerns. Therefore, this study aims to review the mycobiota responsible for producing key mycotoxins in cheese and to assess the influence of physicochemical factors on fungal growth and mycotoxin production. By incorporating control strategies such as hygiene practices, pasteurization, and the use of preservatives, this study seeks to improve methodologies in the cheese production chain and mitigate contamination by fungi and mycotoxins.

Ochratoxin A and AFM1 in Cheese and Cheese Substitutes: LC-MS/MS Method Validation, Natural Occurrence, and Risk Assessment

Cheese is vulnerable to contamination with mycotoxins, particularly ochratoxin A (OTA) and aflatoxin M1 (AFM1). This study aims to develop and validate an analytical method for the detection and quantification of OTA and AFM1 in cheese and to assess their prevalence and associated risks. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was validated for detecting these mycotoxins in 41 cheese samples, including firm-ripened, spreadable, and plant-based alternatives. The results showed that OTA was detected exclusively in grated Parmigiano Reggiano cheese, while AFM1 was found in both Parmigiano Reggiano and Pecorino cheeses. This study goes beyond analytical method development by providing a preliminary exposure assessment and risk characterization for OTA and AFM1 in cheese, bridging the gap between analytical chemistry and public health implications. This study identified potential health risks associated with OTA, particularly for children and adolescents categorized as high consumers of Parmigiano Reggiano cheese. The findings underscore the need for monitoring of OTA and AFM1 in cheese and further research to establish regulatory limits for these contaminants.

Prevalence and concentration of aflatoxin M1 and ochratoxin A in cheese: a global systematic review and meta-analysis and probabilistic risk assessment

Exposure to mycotoxins such as aflatoxins can endanger human health, especially infants and children. In this study, an attempt was made to retrieved studies related to the concentration of aflatoxin M1 (AFM1) and ochratoxin A (OTA). Search was performed in international databases such as Embase, PubMed, Scopus, and Web of Science for the period 1 January 2010 to 20 February 2023. Then, the pooled concentration in the defined subgroups was calculated using meta-analysis and the health risk assessment was conducted by margin of exposure (MOEs). Thirty-one scientific papers with 34 data reports (Sample size=2,277) were included in our study. The lowest and highest prevalence of AFM1 in cheese was related to El Salvador (12.18 %) and Serbia (100.00 %). The pooled prevalence of AFM1 was 49.85 %, 95 %CI (37.93-61.78 %). The lowest and highest prevalence of OTA in cheese was related to Türkiye (6.67 %) and Italy (44.21 %). The pooled prevalence of OTA was 35.64 %, 95 %CI (17.16-56.44 %). Health risk of AFM1 revealed that except Pakistan and Iran, MOE in the other countries was lower than 10,000 for adults and also except Pakistan, MOE for other countries was lower than 10,000 for children. Health risk of OTA revealed that except Greece, MOE in the other countries was higher than 10,000 for adults and also except Germany and Greece, MOE for other countries was higher than 10,000 for children. Therefore, it is recommended to conduct control plans to reduce the concentration of mycotoxins in cheese, especially AFM1.

Effect of Major Mycotoxins on Public Health Through the Consumption of Cheese Products

Food safety is a key priority for public health. However, consumer demand for cheese products may expose the population to the risk of mycotoxicosis and cancer, among others. Acute mycotoxicosis and cancer are examples of linked disorders. Among the most frequent toxic agents that enter the human body through food consumption are mycotoxins. This review study highlights the significance of the impact of the most important mycotoxins on public health through the consumption of cheese products. Despite being a poor substrate for mycotoxin development, cheese products have been found to contain harmful toxins. Aflatoxin M1 (AFM1) and ochratoxin A (OTA) are the main mycotoxins in cheese products, and they are very harmful to human health. Adherence to legislative limits and the implementation of appropriate control measures by food business operators (FBOs) are considered necessary to protect consumers' health.

Exploring a Cheese Ripening Process That Hinders Ochratoxin A Production by Penicillium nordicum and Penicillium verrucosum

A lack of control of the technological abiotic parameters apparent during cheese manufacture, including temperature and relative humidity, results in this dairy product being prone to mold contamination. Sometimes, inoculant molds are used to obtain the characteristic sensory properties of this type of product. However, during the maturation process, some unwanted molds can colonize the ripening cheese and produce mycotoxins. Mycotoxigenic molds such as Penicillium nordicum and Penicillium verrucosum can colonize ripened cheeses, contaminating them with ochratoxin A (OTA), a nephrotoxic 2B toxin. Thus, the presence of OTA in cheeses could represent a hazard to consumers' health. This study has evaluated the growth and OTA production of P. nordicum and P. verrucosum on a cheese analogue under simulated ripening conditions of 10 and 15 °C and 0.96 water activity (aw). Ecophysiological, molecular, and analytical tools assessed the mold growth, gene expression, and OTA production under these environmental conditions. Both species were able to effectively colonize the cheese under these ripening conditions. However, neither species expressed the otapks and otanps biosynthetic genes or produced phenotypic OTA. Therefore, these results suggest a relatively low risk of exposure to OTA for consumers of this type of cheese product. The conditions used were thus appropriate for cheese ripening to minimize the potential for contamination with such mycotoxins. An appropriate adjustment of the technological ripening parameters during such cheese manufacture could contribute to OTA-free cheeses.

Occurrence, Risk Implications, Prevention and Control of CIT in Monascus Cheese: A Review

Monascus is a filamentous fungus that has been used in the food and pharmaceutical industries. When used as an auxiliary fermenting agent in the manufacturing of cheese, Monascus cheese is obtained. Citrinin (CIT) is a well-known hepatorenal toxin produced by Monascus that can harm the kidneys structurally and functionally and is frequently found in foods. However, CIT contamination in Monascus cheese is exacerbated by the metabolic ability of Monascus to product CIT, which is not lost during fermentation, and by the threat of contamination by Penicillium spp. that may be introduced during production and processing. Considering the safety of consumption and subsequent industrial development, the CIT contamination of Monascus cheese products needs to be addressed. This review aimed to examine its occurrence in Monascus cheese, risk implications, traditional control strategies, and new research advances in prevention and control to guide the application of biotechnology in the control of CIT contamination, providing more possibilities for the application of Monascus in the cheese industry.

Neoteric Biofilms Applied to Enhance the Safety Characteristics of Ras Cheese during Ripening

The milk's natural flora, or the starter, can preserve cheesemaking and allow for microbial competition. This investigation aimed to improve cheese safety and assess its characteristics using probiotic cell pellets (LCP) or cell-free extracts (CFS). Cheese samples were collected from different areas to investigate the current contamination situation. Six CFSs of probiotics were assessed as antifungal against toxigenic fungi using liquid and solid media and their aflatoxin reduction impact. The most effective CFS was chosen for cheese coating in nanoemulsion. Coated cheese with CFS, LCP, and LCP-CFS was assessed against control for changes in chemical composition, ripening indications, rheological properties, and microbiology. Results showed significant contamination levels in the collected samples, and toxic fungi were present. Lactobacillus rhamnosus CFS has aflatoxins reducibility in liquid media. During cheese ripening, uncoated cheese showed higher fat, protein, salt content, soluble nitrogen, total volatile fatty acids, tyrosine, and tryptophan contents than coated samples, except for LCP-coating treatment. Cheese rheology indicated that coating treatments had the lowest hardness, cohesiveness, gumminess, chewiness, and springiness compared to uncoated cheese. Uncoated cheese had the highest yeast and mold counts compared to the treated ones. The LCP-CFS-coated cheese showed no Aspergillus cells for up to 40 days. Uncoated Ras cheese recorded slightly lower flavor, body, texture, and appearance scores than coated cheeses. In conclusion, coating cheese with L. rhamnosus nanoemulsion has antifungal and antiaflatoxigenic properties, even for LCP, CFS, and CFS-LCP, which could extend cheese shelf life.

Domestication in dry-cured meat Penicillium fungi: Convergent specific phenotypes and horizontal gene transfers without strong genetic subdivision

Some fungi have been domesticated for food production, with genetic differentiation between populations from food and wild environments, and food populations often acquiring beneficial traits through horizontal gene transfers (HGTs). Studying their adaptation to human-made substrates is of fundamental and applied importance for understanding adaptation processes and for further strain improvement. We studied here the population structures and phenotypes of two distantly related Penicillium species used for dry-cured meat production, P. nalgiovense, the most common species in the dry-cured meat food industry, and P. salamii, used locally by farms. Both species displayed low genetic diversity, lacking differentiation between strains isolated from dry-cured meat and those from other environments. Nevertheless, the strains collected from dry-cured meat within each species displayed slower proteolysis and lipolysis than their wild conspecifics, and those of P. nalgiovense were whiter. Phenotypically, the non-dry-cured meat strains were more similar to their sister species than to their conspecific dry-cured meat strains, indicating an evolution of specific phenotypes in dry-cured meat strains. A comparison of available Penicillium genomes from various environments revealed HGTs, particularly between P. nalgiovense and P. salamii (representing almost 1.5 Mb of cumulative length). HGTs additionally involved P. biforme, also found in dry-cured meat products. We further detected positive selection based on amino acid changes. Our findings suggest that selection by humans has shaped the P. salamii and P. nalgiovense populations used for dry-cured meat production, which constitutes domestication. Several genetic and phenotypic changes were similar in P. salamii, P. nalgiovense and P. biforme, indicating convergent adaptation to the same human-made environment. Our findings have implications for fundamental knowledge on adaptation and for the food industry: the discovery of different phenotypes and of two mating types paves the way for strain improvement by conventional breeding, to elucidate the genomic bases of beneficial phenotypes and to generate diversity.

Biocontrol of Pathogen Microorganisms in Ripened Foods of Animal Origin

Ripened foods of animal origin comprise meat products and dairy products, being transformed by the wild microbiota which populates the raw materials, generating highly appreciated products over the world. Together with this beneficial microbiota, both pathogenic and toxigenic microorganisms such as Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus, Clostridium botulinum, Escherichia coli, Candida spp., Penicillium spp. and Aspergillus spp., can contaminate these products and pose a risk for the consumers. Thus, effective strategies to hamper these hazards are required. Additionally, consumer demand for clean label products is increasing. Therefore, the manufacturing sector is seeking new efficient, natural, low-environmental impact and easy to apply strategies to counteract these microorganisms. This review gathers different approaches to maximize food safety and discusses the possibility of their being applied or the necessity of new evidence, mainly for validation in the manufacturing product and its sensory impact, before being implemented as preventative measures in the Hazard Analysis and Critical Control Point programs.

Filamentous fungi in artisanal cheeses: A problem to be avoided or a market opportunity?

The microbial diversity of artisanal cheeses has been ever more extensively explored over recent years. Many new studies have been particularly focused on the detection and identification of fungi associated with cheese rinds. This is not surprising given that the composition and abundance of fungi on the cheese surface can significantly contribute to desirable sensory qualities, while also contributing to defects, particularly during ripening, and risks associated with the production of mycotoxins. Here we critically review the impact of fungi on the quality of artisanal cheeses, as well as the risks associated with the presence of particular species or strains with specific phenotypes. Ultimately, we address the question; should fungi be predominantly considered villains when it comes to artisanal cheese safety or could their presence be better exploited by producers in order to generate innovative products with greater added value? Such discussions will be increasingly important from the perspective of the future commercialization and regulation of artisanal cheeses that frequently contain a high abundance of moulds.

The Mechanism of Ochratoxin Contamination of Artificially Inoculated Licorice Roots

Ochratoxin (OT) contamination of medicinal herbs is a serious threat to human health. This study was performed to investigate the mechanism of OT contamination of licorice (Glycyrrhiza sp.) root. Licorice root samples were cut into eight parts, which were placed separately on sucrose-free Czapek Dox agar medium, inoculated with the spores of ochratoxigenic Aspergillus westerdijkiae. After incubation for 10 and 20 days, the OT contents of the samples were determined by high-performance liquid chromatography, and microtome sections prepared from the samples were analyzed by desorption electrospray ionization tandem mass spectrometry, to visualize OT localization. The same sections were further examined by light microscopy and scanning electron microscopy, to investigate the path of fungal mycelial penetration of the inner roots. OT concentrations tended to increase from the upper- to the middle-root parts. OTs were located in cut areas and areas of cork layer damage; they were not present in the undamaged cork layer, indicating that the structure of this layer prevents OT contamination of the licorice root.

Occurrence of Aflatoxins and Ochratoxin A during Merkén Pepper Powder Production in Chile

Berry fruits of Capsicum annuum L. cv. "Cacho de Cabra" are used for the manufacture of a traditional pepper powder known as Merkén. In the present study, aflatoxins (AFs) and ochratoxin A (OTA) contamination in berry fruits of C. annuum was determined at harvest, drying, and smoking stages of Merkén production, in cumin and coriander seeds used as Merkén ingredients, and in the final packaged Merkén produced by local farmers. Additionally, Merkén samples from local markets in the region of La Araucanía (Chile) were also evaluated. Chromatographic analysis was based on a qualitative method. AFs and OTA were not detected on pepper pods and seeds. There was no detection of AFs and OTA on cultured Aspergillus and Penicillium strains isolated from pepper pods, cumin and coriander seeds and Merkén. The lack of AFs/OTA-producers among the isolated fungal species can explain and support the absence of contamination in pepper pods. In contrast, the AFB₁ was detected in 75% of Merkén obtained from farmers and 46% of Merkén samples purchased from local markets; while OTA was detected in 100% of Merkén samples obtained from farmers and local markets. In the Merkén production chain, the harvest and post-harvest are key stages for fungal growth while the commercialization stage is highly susceptible to AFs and OTA contamination.

Ochratoxin A and Sterigmatocystin in Long-Ripened Grana Cheese: Occurrence, Wheel Rind Contamination and Effectiveness of Cleaning Techniques on Grated Products

A survey on the occurrence of ochratoxin A (OTA) and sterigmatocystin (STC) in grated cheese products obtained from hard grana-type cheeses was carried out, where 107 grated products were collected in retail outlets and analysed. OTA and STC were found in 48.6% and 94.4% of the samples, in a range from <LOD to 25.05 µg kg−1 and from <LOD to 6.87 µg kg−1, respectively. STC was detected in all the OTA-contaminated samples. The OTA and STC occurrence in cheese is due to environmental contamination during ripening, leading to fungal growth and mycotoxin production on the cheese surface. This statement was confirmed by analysing the surface of 16 hard grana cheese rinds, which resulted contaminated by both OTA and STC, with concentration ranging from 3 to 370 µg kg−1. This finding demonstrates that rind inclusion increases the mycotoxin concentration in grated cheeses. The mycotoxin level significantly decreased from the surface (0−1.5 mm) to inner parts of cheese rinds (1.5−4.5 mm). Industrial wheel-cleaning techniques can represent a useful treatment to reduce both toxins in grated cheese products.

Microbial Ecology of French Dry Fermented Sausages and Mycotoxin Risk Evaluation During Storage

Dry fermented sausages are produced worldwide by well-controlled fermentation processes involving complex microbiota including many bacterial and fungal species with key technological roles. However, to date, fungal diversity on sausage casings during storage has not been fully described. In this context, we studied the microbial communities from dry fermented sausages naturally colonized or voluntarily surface inoculated with molds during storage using both culture-dependent and metabarcoding methods. Staphylococci and lactic acid bacteria largely dominated in samples, although some halotolerant genera (e.g., Halomonas, Tetragenococcus, and Celerinatantimonas spp.) were also frequently observed. Fungal populations varied from 7.2 to 9.8 log TFU/cm² sausage casing during storage, suggesting relatively low count variability among products. Fungal diversity identified on voluntarily inoculated casings was lower (dominated by Penicillium nalgiovense and Debaryomyces hansenii) than naturally environment-inoculated fermented sausages (colonized by P. nalgiovense, Penicillium nordicum, and other Penicillium spp. and sporadically by Scopulariopsis sp., D. hansenii, and Candida zeylanoïdes). P. nalgiovense and D. hansenii were systematically identified, highlighting their key technological role. The mycotoxin risk was then evaluated, and in situ mycotoxin production of selected mold isolates was determined during pilot-scale sausage productions. Among the identified fungal species, P. nalgiovense was confirmed not to produce mycotoxins. However, some P. nordicum, Penicillium chrysogenum, Penicillium bialowienzense, Penicillium brevicompactum, and Penicillium citreonigrum isolates produced one or more mycotoxins in vitro. P. nordicum also produced ochratoxin A during pilot-scale sausage productions using “worst-case” conditions in the absence of biotic competition. These data provide new knowledge on fermented sausage microbiota and the potential mycotoxin risk during storage.

Mycotoxigenic and phylogenetic perspective to the yeasts and filamentous moulds in mould-matured Turkish cheese

This study was conducted to determine the diversity of yeasts and filamentous moulds in mould-matured cheese (MMC) consumed in Turkey. Overall, 120 samples were collected from 12 different geographical locations between March 2016 and April 2017. The morphological observation was applied in combination with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and molecular analyses to determine yeasts and filamentous moulds in the cheeses. High-performance liquid chromatography (HPLC) technique was used to evaluate the ability of mycotoxins production of fungal isolates and the presence of mycotoxins in cheese samples. A total of 241 fungi (81 filamentous moulds and 160 yeast) were recovered, and Penicillium roqueforti and Debaryomyces hansenii were the most frequently isolated species in all cheese samples. The rep-PCR results indicated a high level of genetic diversity among fungal isolates, regardless of isolation source or geographical origin. Filamentous mould strains isolated from MMC were found to synthesize at least one mycotoxin (Aflatoxin B₁, B₂, G₁ and G₂, citrinine, cyclopiazonic acid, mycophenolic acid, ochratoxin A, penicillic acid and roquefortine C). Although mycotoxin producing ability was observed from all isolates, none of the cheese samples were found positive for these mycotoxins. AFM₁ was detected in 8 (6.6%) MMC samples from which 2 (1.6%) were above the legal limits (0.05 μg/kg) set by the Turkish Food Codex (TFC) and European Commission (EC). In conclusion, Turkish MMCs were found to be contaminated with toxigenic fungi, so a potential public health risk, while low, exists. Therefore, the selection of nontoxigenic filamentous mould strains for cheese manufacturing and control of the ripening conditions is a critical need to ensure the quality and safety of Turkish MMC.

Knowledge and Behavioral Habits to Reduce Mycotoxin Dietary Exposure at Household Level in a Cohort of German University Students

Mycotoxins pose a health concern for humans. Therefore, strategies at pre- and post-harvest and maximum levels for food have been implemented, aimed to minimize the risk of dietary exposure. Yet, consumers’ dietary habits and life style play a substantial role in overall exposure. The aim of this study was to investigate knowledge of mycotoxins and accordance to behavioral practices or habits that may affect the risk of mycotoxin dietary exposure at the household level or when food commodities are obtained from non-regulated trade markets. For this purpose, an online survey was applied to a university student cohort (n = 186). The survey consisted of 23 questions grouped in five categories: Socio-demographic and income data, general life style and habits, knowledge about mycotoxins, compliance with the “17 golden rules to prevent mycotoxin contamination” of the German Federal Institute for Risk Assessment (BfR), and measures towards reducing health risks. We paid particular attention to knowledge and compliance of a group acquiring food items in markets outside regulation and surveillance, namely, adherents of food movements such as food sharing or dumpster diving. The results of our study indicate a generally rather low level of knowledge about mycotoxins in the investigated cohort, as well as a weak perception of their associated risks compared to similar studies; around half of the cohort was unfamiliar with the term “mycotoxin” and the health risks of mycotoxins were considered comparable to those of pesticides, heavy metals, microplastics and food additives. We observed, in general, a relatively high degree of compliance with the proposed golden rules. The rules with the highest compliance related to deteriorated foods with visible signs of fungal infestation, probably because these are already considered as food waste. Rules that were less followed included those that require a specific knowledge of food storage and early fungal contamination stages, namely preventive measures related to storage of bread. Adherents of food movements did not differ significantly with the control group in terms of knowledge, risk perception and compliance with the 17 golden rules. This may be due to the homogeneity of the cohort in terms of demography, age and educational level. However, significant low compliance in the food movements group was observed with the rules “Buy fruit and vegetables that are as intact as possible, i.e., without injuries and bruises” and “Rotten fruit should neither be eaten nor further processed into compote or jam”, possibly because of ideological convictions around reducing food waste. In conclusion, mycotoxin prevention strategies should not end at the retail level; in particular, clarification and information regarding health risk from mycotoxins are suggested in order to reduce the risk of exposure in private households or in informal trade markets. The results of this study should, however, be interpreted with caution due to the specific characteristics of the cohort in terms of age and educational level and the disparity in size between the control and the food movement group. This study is a starting point for evaluating and understanding the consumer perspective on mycotoxins.

Microbiological quality and safety of Brazilian artisanal cheeses

The establishment of norms that regulates the production and trade of Brazilian Artisanal Cheeses (BAC) has been stimulating many small farmers for this activity. The predominance of lactic acid bacteria (LAB) is a typical characteristic of BAC, which confers desirable attributes to artisanal cheeses. However, these products can be contaminated by other microbial groups, including those that indicate hygienic failures during production and may cause spoilage, or even microorganisms that pose risks to consumers' health. A systematic review of the literature published from January 1996 to November 2020 was carried out to identify scientific data about production characteristics and microbiological aspects of BAC, with a major focus on quality and safety status of these traditional products. Studies that fulfilled the inclusion criteria indicated that artisanal chesses produced in Brazil still do not satisfactorily meet the microbiological criteria established by the national laws, mainly due to the high counts of coagulase-positive Staphylococcus and coliforms. Despite low prevalence, pathogens such as Salmonella and Listeria monocytogenes were isolated in some BAC. This review contributed to better understanding microbiological aspects of BAC, the data compiled by the authors highlight the need to improve hygiene practices along the production chain of these traditional cheeses.

The Influence of NaCl and Glucose Content on Growth and Ochratoxin A Production by Aspergillus ochraceus, Aspergillus carbonarius and Penicillium nordicum

Ochratoxin A (OTA) is a nephrotoxic mycotoxin, which deserves particular attention for its widespread contamination of a variety of food and feed. Aspergillus ochraceus, Aspergillus carbonarius, and Penicillium nordicum are an important source of OTA in three different kinds of food commodities, including cereals, grape and dried fruit products, and dry-cured meat products. Deeper knowledge of OTA production and mycelium growth related to the high-sugar or NaCl-rich environments was gained in this manuscript. A. ochraceus and P. nordicum were likely to have greater growth rates in medium supplied with certain concentrations of NaCl (0–80 g/L), and the colony diameter was the largest at the salt content of 40 g/L. P. nordicum was more suitable to grow in NaCl-riched medium, the OTA production was increased to 316 ppb from 77 ppb when 20 g/L NaCl was added. The capability of OTA production was inhibited when salt content was 40 g/L and 60 g/L in A. ochraceus and P. nordicum, respectively. As the glucose content increased to 250 g/L, the capacity of mycelium growth and sporulation was increased significantly in A. ochraceus and A. carbonarius. A. carbonarius was more suitable to grow in high-sugar grape products. OTA production was significantly promoted with an added 100 g/L glucose in A. carbonarius. OTA production was inhibited when glucose content was 150 g/L and in 200 g/L in A. ochraceus and A. carbonarius, respectively. NaCl and glucose have an effect on fungal growth and OTA production, and the activation of biosynthetic genes of OtaA. These results would allow designing new strategies to prevent OTA accumulation on sugar or NaCl-riched foodstuffs and achieve the objective to manufacture cereals, dried vine fruits and dry-cured ham, free of OTA.

Risk assessment of ochratoxin A in food

The European Commission asked EFSA to update their 2006 opinion on ochratoxin A (OTA) in food. OTA is produced by fungi of the genus Aspergillus and Penicillium and found as a contaminant in various foods. OTA causes kidney toxicity in different animal species and kidney tumours in rodents. OTA is genotoxic both in vitro and in vivo; however, the mechanisms of genotoxicity are unclear. Direct and indirect genotoxic and non-genotoxic modes of action might each contribute to tumour formation. Since recent studies have raised uncertainty regarding the mode of action for kidney carcinogenicity, it is inappropriate to establish a health-based guidance value (HBGV) and a margin of exposure (MOE) approach was applied. For the characterisation of non-neoplastic effects, a BMDL 10 of 4.73 μg/kg body weight (bw) per day was calculated from kidney lesions observed in pigs. For characterisation of neoplastic effects, a BMDL 10 of 14.5 μg/kg bw per day was calculated from kidney tumours seen in rats. The estimation of chronic dietary exposure resulted in mean and 95th percentile levels ranging from 0.6 to 17.8 and from 2.4 to 51.7 ng/kg bw per day, respectively. Median OTA exposures in breastfed infants ranged from 1.7 to 2.6 ng/kg bw per day, 95th percentile exposures from 5.6 to 8.5 ng/kg bw per day in average/high breast milk consuming infants, respectively. Comparison of exposures with the BMDL 10 based on the non-neoplastic endpoint resulted in MOEs of more than 200 in most consumer groups, indicating a low health concern with the exception of MOEs for high consumers in the younger age groups, indicating a possible health concern. When compared with the BMDL 10 based on the neoplastic endpoint, MOEs were lower than 10,000 for almost all exposure scenarios, including breastfed infants. This would indicate a possible health concern if genotoxicity is direct. Uncertainty in this assessment is high and risk may be overestimated.

Modelling Fungal Growth, Mycotoxin Production and Release in Grana Cheese

No information is available in the literature about the influence of temperature (T) on Penicillium and Aspergillus spp. growth and mycotoxin production on cheese rinds. The aim of this work was to: (i) study fungal ecology on cheese in terms of T requirements, focusing on the partitioning of mycotoxins between the rind and mycelium; and (ii) validate predictive models previously developed by in vitro trials. Grana cheese rind blocks were inoculated with A. versicolor, P. crustosum, P. nordicum, P. roqueforti, and P. verrucosum, incubated at different T regimes (10–30 °C, step 5 °C) and after 14 days the production of mycotoxins (ochratoxin A (OTA); sterigmatocystin (STC); roquefortine C (ROQ-C), mycophenolic acid (MPA), Pr toxin (PR-Tox), citrinin (CIT), cyclopiazonic acid (CPA)) was quantified. All the fungi grew optimally around 15–25 °C and produced the expected mycotoxins (except MPA, Pr-Tox, and CIT). The majority of the mycotoxins produced remained in the mycelium (~90%) in three out of five fungal species (P. crustosum, P. nordicum, and P. roqueforti); the opposite occurred for A. versicolor and P. verrucosum with 71% and 58% of STC and OTA detected in cheese rind, respectively. Available predictive models fitted fungal growth on the cheese rind well, but validation was not possible for mycotoxins because they were produced in a very narrow T range.

Polyphasic identification of Penicillium spp. isolated from Spanish semi-hard ripened cheeses

Fifteen samples of semi-hard ripened cheeses, both spoiled (10) and unspoiled (5), and obtained from cheese factories located in Northwest of Spain, were analysed by a dilution plating technique and direct sampling. A total of 32 isolates were identified at species level by a polyphasic approach (phenotypic characterization, partial extrolite analysis and molecular identification). Most isolates (65.6%) belonged to the species P. commune; other species found were P. solitum, P. chrysogenum, P. nordicum, P. expansum and P. cvjetkovicii. All of the P. commune isolates were able to produce cyclopiazonic acid, while the P. nordicum and the P. expansum isolates were producers of ochratoxin A and patulin respectively. Despite this, the role of P. commune as beneficial fungi in cheese ripening should be investigated. Molecular identification based on BenA sequence analysis was able to identify the majority of isolates. The three mycotoxins investigated can be considered key for identification. The polyphasic approach seems to be a very valuable tool for identification of isolates of this complex genus.