Mycotoxin migration in jam samples: a study on natural contamination and experimental inoculation

Fruits, such as apricots, cherries, raspberries, and strawberries, are very often processed into jams to extend their shelf life. Jams are highly appreciated by consumers, and their storage conditions are important for preserving their quality. This study investigates the impact of storage on the microbiological quality and physicochemical parameters of five commercial fruit (apricot, sour cherry, white cherry, raspberry, and strawberry) jams. The pH, titratable acidity, moisture, sugar content, viscosity, and color were evaluated immediately after opening the jam containers and during storage at 2-4 °C and 20 °C. The total number of mesophilic aerobic germs (TMAG) and the total number of yeasts and molds (TYM) were also determined. The samples were analyzed during storage at 14, 42, and 56 days after opening the jam jars. The pH of the fruit jam samples varied from 2.91 (strawberry jam) to 3.47 (sour cherry jam) and decreased during storage, while the titratable acidity (TA) ranged from 0.46 (cherry and raspberry jams) to 0.52% malic acid (apricot jam) and increased during storage, regardless of the storage temperature. The moisture content was between 15.78% (apricot jam) and 21.82% (raspberry jam), and decreased in all the jam samples during storage. The sugar content (30.40-44.59 g per 100 g of jam) was typical for low-sweetened jams and increased during storage. Also, the viscosity of the fruit jam samples increased during storage (more in the samples stored at room temperature). Under the storage conditions, all the jam samples lost their specific color. Immediately after opening the jam jars, no yeasts or molds were found in the apricot and sour cherry jam samples. The highest number of yeasts and molds was detected in the white cherry jam samples (4.25 log10 CFU/g). The TYM increased during storage, as did the TMAG. The time-temperature interaction factor influenced the physicochemical and microbiological properties of the jam samples.

The aim of this study was to evaluate microbiological, physicochemical, instrumental, and sensory parameters of jerky and biltong and to identify potential associations affecting their overall quality and safety. In total, 39 samples of various types of jerky (beef, turkey, venison, pork, and chicken) and 7 samples of beef biltong were analysed. The jerky and biltong samples showed low water activity values (aw < 0.800), which makes them microbially stable products that can be stored at room temperature without the risk of further bacterial growth. Listeria monocytogenes was not detected in any of the 92 analysed samples. From a food safety perspective, the finding of Salmonella Enteritidis in one chicken jerky sample was unacceptable. Total viable count (TVC) values showed high variability, with findings over 8 log CFU/g. These high TVC values indicate heavily contaminated meat used to prepare dried products, or errors in the technological process that allowed bacterial growth. Both are unacceptable from a food quality and safety perspective. This means that more attention needs to be paid to the production process by processors, as well as by competent authorities. The analyses confirmed a high average protein content (>50%) in the final products and a low average fat content (<8%). The average salt content exceeded 3.0% and there was no statistically significant difference between the samples (p > 0.05). Similarly, there was no difference in TBARS values (p > 0.05). Microbial counts (TVC, lactic acid bacteria, and Enterobacteriaceae) were strongly affected by water activity, which was strongly negatively correlated with dry matter and its components such as proteins and ash/NaCl.

Diversification of food is the key factor for enhancing physicochemical properties, nutritional status and consumer satisfaction. Hence, mixed fruits jam was developed from coconut and pineapple pulps in varied ratios (1:1, 3:1 and 1:3). Moisture, lipid, protein, fiber, ash and total carbohydrate contents of different jam samples varied significantly (p≤0.05) and found values in the ranges 26.78-29.15%, 4.12-10.81%, 0.56-1.13%, 1.51- 3.12%, 0.30-0.37% and 62.69-67.91% respectively. Storage stability of the jam samples was analyzed for 6 months keeping under refrigerated (4°C) and room (30°C) temperatures. Physicochemical properties such as total soluble solids, acidity, pH and reducing sugar content were evaluated at 2-months intervals. The parameters were changed variedly due to compositional variances, packaging materials and storage temperatures. Total soluble solids, acidity and reducing sugar content increased gradually while pH declined upon extension of storage period. Sensory properties for color, taste, flavor, texture and overall acceptability of jam samples were tested where sample with pineapple and coconut in the ratio 3:1 showed the best result than others. Samples were also analyzed for yeast and mold count at the end of the storage period and positive result was found in case of samples packed in plastic containers kept under room temperature. The study yields diversified jam samples with better nutritional and sensory properties with satisfactory shelf life.

Diarrhoeal diseases kill an estimated 2.5 million people each year, the majority being children under 5 years (Kosek et al. 2003). An estimated 4 billion cases annually account for 5.7% of the global burden of disease and place diarrhoeal disease as the third highest cause of morbidity and sixth highest cause of mortality (Pruess et al. 2002). Among children under 5 years in developing countries, diarrhoeal disease accounts for 21% of all deaths (Parashar et al. 2003). By inhibiting normal consumption of foods and adsorption of nutrients, diarrhoeal diseases are also an important cause of malnutrition, leading to impaired physical growth and cognitive development (Guerrant et al. 1999), reduced resistance to infection (Baqui et al. 1993) and potentially long-term gastrointestinal disorders (Schneider et al. 1978). Infectious agents associated with diarrhoeal disease are transmitted chiefly through the faecal-oral route (Byers et al. 2001). A wide variety of bacterial, viral and protozoan pathogens excreted in the faeces of humans and animals are known to cause diarrhoea. Many of these are potentially waterborne – transmitted through the ingestion of contaminated water (Leclerc et al. 2002). Accordingly, a number of interventions have been developed to treat water. These include (i) physical removal of pathogens (e.g. filtration, adsorption and sedimentation); (ii) chemical treatment (e.g. assisted sedimentation, chemical disinfection and ion exchange); or (iii) heat and ultra violet (UV) radiation. Because of the risk of recontamination (Clasen & Bastable 2003), interventions to improve water quality also include steps to maintain the microbiological quality of safe drinking water, such as piped distribution, residual disinfection and improved storage. These efforts are expected to receive additional priority as a result of the United Nation’s commitment to reduce by one-half of the 1.5 billion people without sustainable access to improved water, one of the United Nation’s Millennium Development Goals (United Nations 2000), and by the World Health Organization’s steps to accelerate the health gains of safe water to the remaining population by improved treatment and storage of water at the household level (Sobsey 2002). Health authorities generally accept that safe water plays an important role in preventing outbreaks of diarrhoeal disease (Hunter 1997). Accordingly, the most widely accepted standard for water quality allows no detectable level of harmful pathogens at the point of distribution (WHO 1993). However, in those settings in which diarrhoeal disease is endemic, much of the epidemiological evidence for increased health benefits following improvements in the quality of drinking water has been equivocal (Esrey & Habicht 1986; Lindskog et al. 1987; Cairncross 1989). As many of these same waterborne pathogens are also transmitted via ingestion of contaminated food and other beverages, by person-to-person contact, and by direct or indirect contact with infected faeces, improvements in water quality alone may not necessarily interrupt transmission (Briscoe 1984). As a result of this variety of risk factors, interventions for the prevention of diarrhoeal disease not only include enhanced water quality but also steps to (i) improve the proper disposal of human faeces (sanitation), (ii) increase the quantity and improve access to water (water supply), and (iii) promote hand washing and other hygiene practices within domestic and community settings (hygiene). As in the case of studies of water quality, there is a wide range in the reported measure of effect on diarrhoea morbidity of each of these other environmental interventions (Esrey et al. 1985). Even more fundamentally, there are also questions about the methods and validity of studies designed to assess the health impact of such interventions (Briscoe et al. 1986; Imo State Evaluation Team 1989). As part of a larger evaluation of interventions for the control of diarrhoeal disease (Feachem et al. 1983), Esrey et al. (1985) reviewed 67 studies to determine the health impact from improvements in water supplies and excreta disposal facilities (Esrey et al. 1985). The median reduction in diarrhoeal morbidity from improved water quality was 16% (range 0–90%). This compared with 22% for Tropical Medicine and International Health

Like bacteria and plants, fungi produce a remarkable diversity of small molecules with potent activities for human health known as natural products or secondary metabolites. One such example is mycophenolic acid, a powerful immunosuppressant drug that is administered daily to millions of transplant recipients worldwide. Production of mycophenolic acid is restricted to a very limited number of filamentous fungi, and little is known about its biosynthetic modalities. It is therefore a particular challenge to improve our knowledge of the biosynthesis of this valuable natural compound, as this would contribute to a better understanding of the specialized metabolism of fungi and could also lead to the identification of new fungal producers for the supply of immunosuppressants. Here, we were interested in deciphering the origin and evolution of the fungal mycophenolic acid biosynthetic pathway. Large-scale analyses of fungal genomic resources led us to identify several new species that harbor a gene cluster for mycophenolic acid biosynthesis. Phylogenomic analysis suggests that the mycophenolic acid biosynthetic gene cluster originated early in a common ancestor of the fungal family Aspergillaceae but was repeatedly lost and it is now present in a narrow but diverse set of filamentous fungi. Moreover, a comparison of the inosine 5′-monophosphate dehydrogenase protein sequences that are the target of the mycophenolic acid drug as well as analysis of mycophenolic acid production and susceptibility suggest that all mycophenolic acid fungal producers are resistant to this toxic compound, but that this resistance is likely to be based on different molecular mechanisms. Our study provides new insight into the evolution of the biosynthesis of the important secondary metabolite mycophenolic acid in fungi.

This handbook compiles authoritative information about fungal metabolites and their chemistry and biotechnology. The first in the reference work series “Phytochemicals”, and written by a team of international expert authors, this book provides reference information ranging from the description of fungal natural products, over their use e.g. as anticancer agents, to microbial synthesis, even spanning to the production of secondary metabolites on industrial scale. On the other hand it also describes global health issues related to aflatoxin production in foods and agriculture, including perspectives for detoxification. The handbook characterizes different compound classes derived from fungal secondary metabolites, like ergot alkaloids and aflatoxins. The discussion puts a special emphasis on how potentially useful compounds can be obtained and what applications they can find, on the one hand, and how potential dangers can be encountered on the other hand. The comprehensive chapters in this handbook will thus appeal to readers from diverse backgrounds in chemistry, biology, life sciences, and even medicine, who are working or planning to work with fungal (secondary) metabolites and their application. They provide the readers with rich sources of reference information on important topics in this field. The first authoritative summary and reference work on fungal (secondary) metabolites, their chemistry and biotechnological use and applications Covering aspects from beneficial use, to potential health issues of fungal metabolites Reference information for readers from various backgrounds: chemists, biologists, life scientists, medical scienti The biocontrol of plant pathogenic fungi includes two complementary approaches depending on whether the aim is to control soil-borne or air-borne pathogenic fungi. In the first case, natural biotic interactions within the indigenous microflora should be stimulated to regulate inoculum density and the infectious activity of pathogen populations. This strategy can be enhanced by inoculating one or more previously selected biocontrol agents. In the second case, one or more previously selected biocontrol agents can be sprayed on plant foliage to interfere with the development of the targeted pathogen through different mechanisms involving particular enzymes or metabolites. Selecting the most effective biological control agents implies (i) knowing the mechanisms of their interactions with the pathogens and (ii) checking that the environment in which the biocontrol agent is introduced will permit the expression of these mechanisms. The common thread of this chapter is the impressive diversity of metabolites and proteins produced by fungi and involved in interactions between pathogenic and nonpathogenic fungi. Many metabolites and proteins were discovered empirically or by chance a few decades ago, and what we knew about them was they inhibited the growth of pathogenic models on agar medium. Fungi producing these metabolites were not well-known fungal species and were not used as biocon- trol agents. However, the demonstration of their intense metabolic activity paved the way for more investigations in this area and led to deciphering the mechanisms of interactions between fungal strains. Thus, in recent years a large number of enzymes, signal molecules, secondary metabolites, large-size proteins, as well as new metabolic pathways have been revealed by genomics, and it is now possible to understand why some strains can control a given pathogen more than others or stimulate plant defense reactions. To date, the most studied fungi include many strains of the genus Trichoderma but also the species Chlonostachys rosea, Coniothyrium minitans, Verticillium biguttatum, and the oomycete Pythium oligandrum. All of them are successfully used as biocontrol agents. This chapter does not aim to provide a comprehensive catalog, but rather to associate these metabolites and proteins to the modes of action involved in pathogen control. The state of the art presented in this review suggests promising prospects for rational, appropriate, and effective use of the biocontrol potential offered by the huge diversity of fungal metab- olites and proteins.

The filamentous fungus Penicillium roqueforti is widely known as the ripening agent of blue-veined cheeses. Additionally, this fungus is able to produce several secondary metabolites, including the meroterpenoid compound mycophenolic acid (MPA). Cheeses ripened with P. roqueforti are usually contaminated with MPA. On the other hand, MPA is a commercially valuable immunosuppressant. However, to date the molecular basis of the production of MPA by P. roqueforti is still unknown. Using a bioinformatic approach, we have identified a genomic region of approximately 24.4 kbp containing a seven-gene cluster that may be involved in the MPA biosynthesis in P. roqueforti. Gene silencing of each of these seven genes (named mpaA, mpaB, mpaC, mpaDE, mpaF, mpaG and mpaH) resulted in dramatic reductions in MPA production, confirming that all of these genes are involved in the biosynthesis of the compound. Interestingly, the mpaF gene, originally described in P. brevicompactum as a MPA self-resistance gene, also exerts the same function in P. roqueforti, suggesting that this gene has a dual function in MPA metabolism. The knowledge of the biosynthetic pathway of MPA in P. roqueforti will be important for the future control of MPA contamination in cheeses and the improvement of MPA production for commercial purposes.

Effect of certain chemical compounds on secondary metabolites of Penicillium janthinellum and P. duclauxii

Soil-occupant fungi produce a variety of mycotoxins as secondary metabolites, one of which is mycophenolic acid (MPA), an antibiotic and immunosuppressive agent. MPA is mainly produced by several species of Penicillium, especially Penicillium brevicompactum. Here, we present the first report of MPA production by a local strain belonging to Penicillium glabrum species. We screened ascomycete cultures isolated from moldy food and fruits, as well as soils, collected from different parts of Iran. MPA production of one hundred and forty Penicillium isolates was analyzed using HPLC. Three MPA producer isolates were identified, among which the most producer was subjected to further characterization, based on morphological and microscopic analysis, as well as molecular approach (ITS, rDNA and beta-tubulin gene sequences). The results revealed that the best MPA producer belongs to P. glabrum IBRC-M 30518, and can produce 1079 mg/L MPA in Czapek-Dox medium.

Many Fungi have a well-developed secondary metabolism. The diversity of fungal species and the diversification of biosynthetic gene clusters underscores a nearly limitless potential for metabolic variation and an untapped resource for drug discovery and synthetic biology. Much of the ecological success of the filamentous fungi in colonizing the planet is owed to their ability to deploy their secondary metabolites in concert with their penetrative and absorptive mode of life. Fungal secondary metabolites exhibit biological activities that have been developed into life-saving medicines and agrochemicals. Toxic metabolites, known as mycotoxins, contaminate human and livestock food and indoor environments. Secondary metabolites are determinants of fungal diseases of humans, animals, and plants. Secondary metabolites exhibit a staggering variation in chemical structures and biological activities, yet their biosynthetic pathways share a number of key characteristics. The genes encoding cooperative steps of a biosynthetic pathway tend to be located contiguously on the chromosome in coregulated gene clusters. Advances in genome sequencing, computational tools, and analytical chemistry are enabling the rapid connection of gene clusters with their metabolic products. At least three fungal drug precursors, penicillin K and V, mycophenolic acid, and pleuromutilin, have been produced by synthetic reconstruction and expression of respective gene clusters in heterologous hosts. This review summarizes general aspects of fungal secondary metabolism and recent developments in our understanding of how and why fungi make secondary metabolites, how these molecules are produced, and how their biosynthetic genes are distributed across the Fungi. The breadth of fungal secondary metabolite diversity is highlighted by recent information on the biosynthesis of important fungus-derived metabolites that have contributed to human health and agriculture and that have negatively impacted crops, food distribution, and human environments.

Determination of hydroxymethylfurfural in commercial jams and in fruit-based infant foods

Barley genotypes with known field reactions to fusarium head blight (FHB) were evaluated for partial disease resistance (PDR) components using an in vitro detached leaf assay. The detached leaves were inoculated with Fusarium graminearum or F. culmorum and incubated at room (21 ± 2 °C) or low temperature (10 ± 1 °C). Both species were pathogenic and had a shorter incubation period and produced larger lesions at room temperature. Inoculation with F. culmorum produced less well-delineated necrotic lesions compared with those from inoculation using F. graminearum under both temperature regimes. On susceptible genotypes, inoculation with F. graminearum at room temperature resulted in significantly shorter latent and incubation periods, larger lesions and more macroconidial production compared with resistant genotypes. Inoculation with F. culmorum resulted in no significant differences in any PDR components measured. Several PDR components for F. graminearum, including latent period, lesion size and macroconidial production, were found to be significantly correlated. There was a negative correlation between incubation period and field ratings in one of three tests, latent period and field ratings in two of three tests, and a positive correlation between lesion size and field disease severity ratings for FHB only in one of three tests. Few PDR components for F. culmorum were found to be significantly correlated with each other. Overall, the best differentiation between resistant and susceptible barley genotypes resulted from inoculation with F. graminearum at room temperature, including a significant correlation between incubation and latent periods with field ratings. In general, given the variability observed, especially in relation to field ratings for FHB, measurement of PDR components cannot be routinely used to complement field-based ratings. However, the measurement of latent period did show promise as it was correlated to field ratings in two of three tests and as such measurement of latent period may be useful in identifying genotypes highly susceptible or resistant to FHB. Further research is required to evaluate the potential of using a detached leaf assay to complement field screening for FHB resistance.

Mycophenolic acid (MPA) is an immunosuppressive/antibiotic drug, biologically produced by the fermentation of Penicillium brevicompactum as its secondary metabolite using submerged (SmF) and solid-state (SSF) fermentation processes. In this study, the SSF of P. brevicompactum (MTCC 1999) was done in optimised conditions to enhance MPA yield. Substrates including basmati and non-basmati rice, barley, oats, cornflakes, rice bran, and wheat bran were 80% moistened and sterilised. The active-spore suspension was inoculated and incubated for 30 days. Wheat bran has been shown to produce the highest MPA yield in bench-scale studies. Therefore, wheat bran was subjected to large-scale MPA production. The indigenous fermentation bags were used in the large-scale SSF process. The MPA production was increased from 0.02 mg/g in bench-scale SSF to 9.5 mg/g in large-scale SSF in 15 days of incubation. The MPA increase is nearly 9.48 mg/g. This paper presents an improved SSF process for enhanced MPA production.

Ripening of blue-veined cheeses, such as the French Bleu and Roquefort, the Italian Gorgonzola, the English Stilton, the Danish Danablu or the Spanish Cabrales, Picón Bejes-Tresviso, and Valdeón, requires the growth and enzymatic activity of the mold Penicillium roqueforti, which is responsible for the characteristic texture, blue-green spots, and aroma of these types of cheeses. This filamentous fungus is able to synthesize different secondary metabolites, including andrastins, mycophenolic acid, and several mycotoxins, such as roquefortines C and D, PR-toxin and eremofortins, isofumigaclavines A and B, and festuclavine. This review provides a detailed description of the main secondary metabolites produced by P. roqueforti in blue cheese, giving a special emphasis to roquefortine, PR-toxin and mycophenolic acid, and their biosynthetic gene clusters and pathways. The knowledge of these clusters and secondary metabolism pathways, together with the ability of P. roqueforti to produce beneficial secondary metabolites, is of interest for commercial purposes.

Temperature, water, solar radiation, and atmospheric CO2 concentration are the main abiotic factors that are changing in the course of global warming. These abiotic factors govern the synthesis and degradation of primary (sugars, amino acids, organic acids, etc.) and secondary (phenolic and volatile flavor compounds and their precursors) metabolites directly, via the regulation of their biosynthetic pathways, or indirectly, via their effects on vine physiology and phenology. Several hundred secondary metabolites have been identified in the grape berry. Their biosynthesis and degradation have been characterized and have been shown to occur during different developmental stages of the berry. The understanding of how the different abiotic factors modulate secondary metabolism and thus berry quality is of crucial importance for breeders and growers to develop plant material and viticultural practices to maintain high-quality fruit and wine production in the context of global warming. Here, we review the main secondary metabolites of the grape berry, their biosynthesis, and how their accumulation and degradation is influenced by abiotic factors. The first part of the review provides an update on structure, biosynthesis, and degradation of phenolic compounds (flavonoids and non-flavonoids) and major aroma compounds (terpenes, thiols, methoxypyrazines, and C13 norisoprenoids). The second part gives an update on the influence of abiotic factors, such as water availability, temperature, radiation, and CO2 concentration, on berry secondary metabolism. At the end of the paper, we raise some critical questions regarding intracluster berry heterogeneity and dilution effects and how the sampling strategy can impact the outcome of studies on the grapevine berry response to abiotic factors.