Aflatoxigenic Molds Research Articles

Inhibitory Effects of Bacillus subtilis Isolated from Meju (Fermented Soybean Brick) on the Growth of Aspergillus parasiticus

Background: Meju is a base material for making soy sauce, soybean paste, and red chili pepper paste, which are representative ingredients of Korean cuisine. Objectives: This study aimed to isolate a predominant bacterial strain of B. subtilis from meju and to observe its inhibitory effects on an aflatoxigenic mold. Methods: We used yellow soybeans (Glycine max (L.) Merr.) grown in South Korea, and meju was produced according to the recommended methods of the Korea Food Research Institute. The identification of the strain was conducted based on its morphological and biochemical characteristics and 16S rDNA sequence. Evaluation of the bacterial effect against A. parasiticus ATCC 15517 was done in yeast extract–sucrose broth at 28 °C. Its inhibitory effect was evaluated using two approaches: mycelial weight and aflatoxin production. Aflatoxins were determined using high-performance liquid chromatography. Results: In the meju samples fermented for three months, a B. subtilis strain, K-0924 was identified. At the end of the incubation period of A. parasiticus, dry mycelial weight was significantly reduced by more than 80% (p < 0.01) and total aflatoxin production was inhibited by more than 63% (p < 0.05) in the presence of B. subtilis. Conclusions: These results indicate that B. subtilis K-0924 inhibits the growth and aflatoxin production of toxigenic Aspergillus, which can be contaminated with meju. We could expect more inhibition by other bacteria related to fermentation of meju, and further examination is necessary on species other than B. subtilis.

Evaluation of Lactic Acid Bacteria for the Control of Aflatoxin Contamination in Silage

This study evaluated the effect of lactic acid bacteria (LAB) on fermentation and aflatoxin concentrations of napier grass, whole crop green maize and whole crop dry maize plant silages, infested with aflatoxigenic mold <i>Aspergillus flavus. </i>The forage was chopped into 10kg portions in duplicates and inoculated with 100 ml of 10^6-7CFU/ml, B2 27 <i>Lb. plantarum/pentosus/paraplantarum </i>(LAB1); B410<i>Lb. plantarum/pentosus/paraplantarum</i> (LAB 2); LAB 1 + 100 ml of cultured spores (100 cfu/ml) of mold; LAB 2 + 100 ml of cultured spores (100 cfu/ml) of mold<i>; </i>control 1- no addition; control 2 – mold only; control 3 – LAB 1 only; control 4 – LAB 2 only. The inoculated silage bags were sealed for 90 days and sampling done monthly to evaluate LAB, fungal counts and aflatoxin B1. Dry matter (DM), pH, crude protein (CP), neutral detergent fiber (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) were determined using AOAC methods. Mold population decreased in month one but increased thereafter. Silage type determined LAB (<i>p </i>= 6.2e-08) and mold (<i>p</i>= 3.9e-08) proliferation. Dry maize and napier grass silages favoured LAB and mold growth, respectively. LAB inhibited mold growth and aflatoxin production (<i>p</i>= 2.2e-04). Silage pH in the third month ranged between 4.55 – 5.67 with no smell of butyric acid. Though napier and dry maize plants showed higher nutritional qualities, they favoured mold growth and aflatoxin proliferation. Aflatoxin-inhibiting LAB starters are useful in controlling aflatoxin risk in silage.

The Implication of Aflatoxin B1 Contamination Through Dietary Intake of Farm Products Sold at Selected Markets in Damaturu, Yobe State, Nigeria

A survey was conducted on 100 farm products sold at selected markets in Damaturu to access the levels of AFB1 contamination using enzyme-linked immunosorbent assay (ELISA). The samples collected include; 20 g each of cereals (rice, millet, maize paste 1, maize 2 and wheat flour), legumes (red beans, groundnut 1, soya bean, white beans, groundnut 2), vegetables (spinach, red onions, garlic, egusi, baobab leaves (kuka) hot pepper, sweet pepper, clove 1, clove 2, moringa, locust bean, okra, dried ginger) and tuber (white cassava). A food sample questionnaire was used to determine the frequency of food consumed and consumption rates. Results of the study revealed that one of the Aflatoxigenic moulds (Aspergillus Niger) is associated with cereal/legume products from both open and stored markets except for protein, minerals, and tuber products. A. flavus (66.67%), A parasiticus (66.67%), Fusarium (50%), and A flavus (50) were associated with cereals, legumes, and beverages in stored markets respectively. The cereal products collected from open and stored markets were found to be contaminated with AFB1 at concentrations of 0.9ppb and 4.1ppb respectively. However, Protein and tuber products were found to be free of any contamination. AFB1 was recorded in beverages(0.66ppb), cereals/legumes (0.37ppb), and minerals (0.5ppb) under the stored market, these results are lower than the limits established by NAFDAC of 10ppb on ready-to-eat foods and 20ppb on other food items. Based on the results obtained, cereal-based food recorded the highest consumption (16.98kg – 88kg) rate per day among the different individuals in each age group while beverages recorded the lowest consumption (1.5g-8.0g) rate per day. The estimated daily intake of AFB1 from individual age groups based on the consumption of different types of food ranged from 0.03-1.16 ng kg-1 body weight day-1. These results suggest that the dietary intake of AFB1, in Damaturu has no adverse health effects on the population.

Effect of Hybrid Nanomaterial of Copper-Chitosan against Aflatoxigenic Fungi in Poultry Feed

In the past decades, the application of nanotechnology indicated significant improvements in animal health. In the present work, 60 samples of poultry feeds were examined, including 20 samples for each yellow corn, soya bean, and processed feed. The prevalence of total fungi was reported as 100%, 95%, and 100% in yellow corn, soya bean, and processed feed, respectively. Toxin-producing Aspergillus flavus represented 75% of isolates from yellow corn, 88% from soya bean meal, and 50% from processed feed. Aflatoxins were found in 88%, 60%, and 80% of yellow corn, soya bean, and processed feed with mean levels of 18.5 ± 3.216.0 ± 4.08.3 ± 1.7 ppm, respectively. The copper nanoparticles embedded with chitosan were green synthesized using an eco-friendly method, and their antifungal activity was evaluated against aflatoxigenic mold that recovered from poultry feeds. However, the molecular detection of virulent genes of Aspergillus flavus (aflR gene) after their exposure to high doses of copper-chitosan nanoparticles (CuCh-NPs) 150 µg/ml prevents aflR gene expression. The embedded chitosan with copper nanomaterial helps decrease their suspected toxicity to animals by reducing the used doses. Hence, the use of nanocomposites of nanomaterials with green benefits substances, such as chitosan, was the essential strategy of field application in veterinary.

Determination of Aflatoxin Concentrations in Cereals and Legumes Marketed in Zaria Metropolis, Kaduna State, Nigeria

Aflatoxins are group of secondary fungal metabolites produced by Aspergillus species, such as Aspergillus flavus and Aspergillus parasiticus. The aflatoxin producing moulds can grow on cereals and legumes in the field, poorly dried harvested crops in storage, processed food, and feed products. The study was carried out with the aim to determine the level of aflatoxin contamination of cereals grain and legumes in Zaria metropolis, Kaduna State, Nigeria. Ninety&#x0D; (90) samples were collected, which comprises of 18 samples each of millet, sorghum, maize, beans, and groundnuts respectively. The samples were subjected to proximate analysis. The grains were further subjected to cultural isolation and microscopic identification. The isolates were then screened for aflatoxin production ability with neutral red desiccated coconut agar and viewed under UV light (365nm). The remaining portions of the samples was grounded and extracted with 80% (v/v) methanol. The enzyme-linked Immunosorbent Assay (ELISA) technique was used in quantifying the total aflatoxin content of the samples. The results revealed that all the cereals and legumes analysed contain organic and inorganic nutrients that can support the growth of aflatoxigenic moulds and production of aflatoxins. Some major parameters such as carbohydrate content, crude protein, crude lipid, and ash contents were statistically significant (p &lt; 0.05). Thirty-one (31) isolates from the 90 samples were confirmed to be A. flavus and seventeen (17) were A. Parasiticus, with percentage occurrence of 34.4% and 18.9% respectively. All the isolates were screened and demonstrated ability for aflatoxin production under Ultra- Violent light (390nm). The results also revealed a high concentration of aflatoxin (11.04 µg/kg) in millet and a low concentration in sorghum (1.07 µg/kg). The contamination levels within the grains were found to be statistically significant (p &lt; 0.05). Aflatoxin contaminations also occurred in 48 samples out of the 90 samples analysed. The grains samples analysed were found to be contaminated with varying amounts of aflatoxins, which is harmful to humans and animals. Therefore, steps should be taken to ensure that grains are properly dried prior to storage.

INCIDENCE OF MYCOTOXINS IN MOULDY SMOKED DRIED FISH AND MEAT (KUNDI) MARKETED IN SOUTHWESTERN NIGERIA

The mycotoxicological safety of 85 mouldy dried fish (n=40) and meat (n=45) samples purchased from Ijebu-ode, Ogun State and Aleshinloye, Ibadan, Oyo State markets both in South Western part of Nigeria respectively, was assessed due to heavy consumption of these animal protein sources by many low-income families in Nigeria. The presence of aflatoxigenic moulds and levels of aflatoxins in the samples were determined by the dilution plating technique and high performance thin-layer chromatographic method. The predominant fungal species isolated from the samples was Aspergillus niger-clade (49.65%); other species isolated include Aspergillus section Flavi (36.83%) and (13.52%). All samples analysed for mycotoxin presence were contaminated with aflatoxin B1. Aflatoxin B2, G1 and G2 were below detectable limits. About 13% of the samples had aflatoxin B1 concentration higher than the maximum acceptable level (10 ng/g). Results imply that the consumption of mouldy dried meat can result in serious public health hazard and hence there is need for advocacy programs to enlighten the populace on proper processing and storage of meat products.

Inactivation of aflatoxin producing molds by selected and broadband infrared wavelength treatments, and the effects of the treatments on rice milling quality

This study investigated the impacts of selected and broadband infrared (IR) wavelength treatments with tempering step on inactivation of aflatoxigenic molds and the treatments’ effects on head rice yield (HRY). Rough rice was treated with different IR intensities, product-to-emitter gaps, and heating durations. Afterward, the samples were tempered at 60°C for 4 hr. Selected IR wavelength treatment at intensities of 15.71 and 10.08 kW/m2 for 20 and 30 s resulted in complete aflatoxigenic mold inactivation; broadband IR wavelength treatment with intensity of 10.84 kW/m2 for 30 s resulted in 1.09 log (cfu/g) reduction in aflatoxigenic mold load. Selected IR wavelength treatment (15.71 kW/m2 for 30 s) resulted in 7 percentage points reduction in the mean HRY. Incorporating a tempering step into treatments at IR intensities of 15.71, 10.08, 7.27, and 4.13 kW/m2 resulted in a complete aflatoxigenic mold inactivation. Also, tempering increased the mean HRY of the treated samples. Practical applications After optimizing the IR parameters tested in this study, the selected IR equipment can be scaled up and commercialized. This novel technique can be used to effectively inactivate aflatoxigenic molds and prevent aflatoxin accumulation on rice, while preserving the milling quality of rice.

In vitro Detoxification of Aflatoxin B1 by Calcium Bentonite Clay Supplementation in Aflatoxigenic Mould Contaminated Feeds for Nile Tilapia, Oreochromis niloticus (Linnaeus, 1758)

Aflatoxins are toxic, carcinogenic secondary metabolites mainly produced by Aspergillus flavus fungi that is often detected in food and agricultural commodities. Calcium bentonite clay has been used historically as an anti-caking agent and a feed binder and demonstrated the ability to bind aflatoxins. Feed samples were prepared for Nile tilapia to determineaflatoxin detoxification properties of calcium bentonite clay. 0.5%, 1%, 1.5% and 2% of this clay was incorporated into Aspergillus flavus contaminated feed and labeled as TF1, TF2, TF3, TF4, and TF5 respectively. The determination and quantification of aflatoxins produced by the fungus in the feed samples were carried out by HPTLC method. The RF values of all the feed samples were confirmed to be the presence of aflatoxin B1 and AFB2, G1 and G2 toxins were not found in any of the samples. Results from this study revealed that the calcium bentonite clay at 2% effectively reduced AFB1 toxin by its adsorption properties. Moreover, calcium bentonite clay improved water stability, water absorption rate with minimal disintegration and nutrients leaching of feed samples in water.

Growth Inhibition of Aflatoxigenic Molds and Biodegradation of Aflatoxin B1 by Certain Bacterial Isolates

AFLATOXIN B1 (AFB1) is mutagenic, carcinogenic, and harmful to humans and animals. Different physical and chemical methods have been proposed to reduce mycotoxins but few have been approved for practical application. This study investigated the possible use of certain bacterial species were isolated from different agricultural soils as biological control agents against the growth of toxigenic Aspergillus flavus and Aspergillus parasiticus isolated from sorghum and peanuts as well as biodegradation of aflatoxin B1 (AFB1). Out of these 30 bacterial isolates, 6 isolates showed that have antagonistic effects against the aflatoxigenic fungi but with varying efficiencies. The six different isolates were screened for their ability to degrade AFB1. Out of 6 isolates, one isolate showed high reduction activity of AFB1. Maximum antifungal activities were observed in one isolate was identified as Staphylococcus lentus. S. lentus completely prevented the A. flavus and A. parasiticus growth and completely degraded AFB1 in Liquid Culture. LC-MS/MS analysis revealed that S. lentus resulted in a 96.54% degradation of AFB1, but no products has been detected. In practical application, it was found that S. lentus at concentration of 10 and 25mL kg-1 were completely prevented the growth of A. flavus and A. parasiticus in sorghum and peanuts, respectively, consequently no aflatoxin were produced. According to our information, this is the first study to prove that Staphylococcus lentus has the capability to inhibit the growth of Aspergillus flavus and Aspergillus parasiticus by 100% and degrading AFB1 by 96%.

A REVIEW OF STREET GRILLED MEAT (SUYA) IN BENIN CITY, NIGERIA: A POTENTIAL PUBLIC HEALTH RISK

Suya originated in the northern parts of Nigeria is ready to eat grilled skewered meat products prepared in different forms spiced with locally sourced, commonly produced by the Hausas in Northern Nigeria. It has permeated Nigerian society, being affordable for all and available everywhere. It is produced from boneless meat hung on stick and spiced with peanut cake, salt, vegetable oil and other flavourings followed by roasting around a glowing charcoal fire. It’s generally made with skewered beef, ram, or chicken. Innards such as kidney, liver, and tripe are also used. Suya are of three main forms namely Tsire, Kilishi, and Balangu, and Tsire is the most commonly preferred. In Benin City, which is located in the southern part of Nigeria, Suya has become a very common street food delicacy scattered most major areas and are sold mostly in the evening time, only very few vendors will sell Suya in the day time. Concerns have been raised in many research regarding the public health risk of consuming suya, part of which is food poisoning, as a result microbial contamination such as Bacillus cereus, Staphylococcus aureus, aflatoxigenic molds, Staphylococcus epidermidis, Proteus vulgaris, Klebseilla pneumoniae, Escherichia coli, Candida spp., Salmonella enteritica and Enterobacter spp. Trace metals such as zinc, lead, manganese, iron, and copper have been observed in suya in concentrations exceeding recommended tolerable upper intake levels which can consequently cause serious long term health issues. This study reviews the potential public health risk of consuming street grilled meat (Suya) in Benin City.

The Inhibitory Effect of Wheat Husks Addition on Aflatoxins Production by Aspergillus flavus in Liquid Culture With Various Wheat Compositions as Carbon Sources.

Wheat may be infected by the aflatoxigenic mold Aspergillus flavus during pre- and post-harvest activities. Control strategies reported to manage aflatoxin contamination of wheat are expensive and require extensive testing to verify the absence of toxic secondary metabolites or newly formed compounds. The objective of this study was to develop an in vitro new control strategy based on assessing the influence of wheat husks on aflatoxin production by A. flavus in liquid culture. The results showed that aflatoxin production is significantly influenced by the existence of husks in the wheat forms used as carbon substrates according to the following order: full wheat grains < half-crushed wheat grains < wheat flour 82% < wheat flour 72%. By applying a fractional factorial design and a response surface methodology, maximum aflatoxin production (2.567 ng/mg) was predicted when wheat flour 72% (39 g/l) as a carbon source, yeast extract (5 g/l), and a 75-ml medium volume/250 ml flask were utilized. At this optimized condition, after addition of wheat husk extract, the growth and synthesis of aflatoxins of A. flavus were repressed by 74.85 and 98.72%, respectively. This finding paves the way to examine the antifungal potential of wheat husk constituents and to compare their efficacy with thyme, cinnamon, sweet basil, and coriander essential oils, which possess antimycotic activities. Accordingly, the wheat husk component SiO2 showed the highest growth inhibition (67.04%) and reduction of A. flavus aflatoxins (82.67%). These results are comparable to those obtained from various examined antimycotic essential oils.

Control of Aflatoxigenic Molds by Antagonistic Microorganisms: Inhibitory Behaviors, Bioactive Compounds, Related Mechanisms, and Influencing Factors.

Aflatoxin contamination has been causing great concern worldwide due to the major economic impact on crop production and their toxicological effects to human and animals. Contamination can occur in the field, during transportation, and also in storage. Post-harvest contamination usually derives from the pre-harvest infection of aflatoxigenic molds, especially aflatoxin-producing Aspergilli such as Aspergillus flavus and A. parasiticus. Many strategies preventing aflatoxigenic molds from entering food and feed chains have been reported, among which biological control is becoming one of the most praised strategies. The objective of this article is to review the biocontrol strategy for inhibiting the growth of and aflatoxin production by aflatoxigenic fungi. This review focuses on comparing inhibitory behaviors of different antagonistic microorganisms including various bacteria, fungi and yeasts. We also reviewed the bioactive compounds produced by microorganisms and the mechanisms leading to inhibition. The key factors influencing antifungal activities of antagonists are also discussed in this review.

Retrospective and Prospective Look at Aflatoxin Research and Development from a Practical Standpoint.

Among the array of structurally and toxicologically diverse mycotoxins, aflatoxins have attracted the most interest of scientific research due to their high toxicity and incidence in foods and feeds. Despite the undeniable progress made in various aspects related to aflatoxins, the ultimate goal consisting of reducing the associated public health risks worldwide is far from being reached due to multiplicity of social, political, economic, geographic, climatic, and development factors. However, a reasonable degree of health protection is attained in industrialized countries owing to their scientific, administrative, and financial capacities allowing them to use high-tech agricultural management systems. Less fortunate situations exist in equatorial and sub-equatorial developing countries mainly practicing traditional agriculture managed by smallholders for subsistence, and where the climate is suitable for mould growth and aflatoxin production. This situation worsens due to climatic change producing conditions increasingly suitable for aflatoxigenic mould growth and toxin production. Accordingly, it is difficult to harmonize the regulatory standards of aflatoxins worldwide, which prevents agri-foods of developing countries from accessing the markets of industrialized countries. To tackle the multi-faceted aflatoxin problem, actions should be taken collectively by the international community involving scientific research, technological and social development, environment protection, awareness promotion, etc. International cooperation should foster technology transfer and exchange of pertinent technical information. This review presents the main historical discoveries leading to our present knowledge on aflatoxins and the challenges that should be addressed presently and in the future at various levels to ensure higher health protection for everybody. In short, it aims to elucidate where we come from and where we should go in terms of aflatoxin research/development.

Control of aflatoxigenic mould and aflatoxins in melon seeds using Aframomum danielli indigenous plant

Control of aflatoxigenic mould and aflatoxins in melon seeds using <i>Aframomum danielli</i> indigenous plant

Antifungal Activity of Lactic Acid Bacteria Isolated from Peanuts, Gari, and Orange Fruit Juice against Food Aflatoxigenic Molds

ABSTRACTThis study aims to evaluate the antifungal activity of lactic acid bacteria (LAB) from some Cameroonian food commodities against mycotoxigenic and spoilage molds. Following LAB isolation, the antifungal activity of the isolates was assessed. The organic acids were quantified using high-performance liquid chromatography and the ability of the LAB to reduce mold biomass and aflatoxin production was evaluated. The LAB were identified and the biopreservative potential of strain LO3 was evaluated on tomato paste. Nine percent of the strains isolated showed broad antifungal activity. The activity was due to the effect of organic acids comprising lactic, acetic, 4-hydroxy-3-phenyllactic and 3-phenyllactic acids. Lactobacillus plantarum LO3 exhibiting the highest and broadest antifungal activity was selected and showed the capacity to inhibit fungal growth and aflatoxin production in vitro. Moreover, this strain and its cell-free supernatant showed the ability to prevent aflatoxigenic mold growth in tomato paste without altering its physico-chemical and organoleptic properties.

Inhibitory Effect of PgAFP and Protective Cultures on Aspergillus parasiticus Growth and Aflatoxins Production on Dry-Fermented Sausage and Cheese.

Aflatoxigenic molds can grow and produce aflatoxins on dry-fermented meat and cheese. The small, basic, cysteine-rich antifungal protein PgAFP displays a time-limited inhibitory ability against unwanted molds by increasing reactive oxygen species (ROS), which can lead to increased aflatoxin production. However, calcium abolishes the inhibitory effect of PgAFP on certain Aspergillus spp. To maximize the antifungal effect, this protein may be combined with protective cultures. Yeasts and lactic acid bacteria may counteract the impact of calcium on PgAFP fungal inhibition. The objective of this work was to study the effect of PgAFP and different combined treatments with Debaryomyces hansenii and/or Pediococcus acidilactici against growth of and aflatoxin production by an aflatoxigenic strain of Aspergillus parasiticus in both culture media and dry-fermented foods with low or high calcium levels. Aflatoxins production was increased by PgAFP but dramatically reduced by P. acidilactici in low calcium culture medium, whereas in the Ca-enriched culture medium, all treatments tested led to low aflatoxins levels. To study whether PgAFP and the protective microorganisms interfere with ROS and aflatoxin production, the relative expression of genes foxA, which is involved in peroxisomal β-oxidation, and aflP, which is required for aflatoxin biosynthesis, were evaluated. The aflatoxin overproduction induced by PgAFP seems not to be linked to peroxisomal β-oxidation. The combination of PgAFP and D. hansenii provided a successful inhibitory effect on A. parasiticus growth as well as on aflatoxin production on sliced dry-fermented sausage and cheese ripened up to 15 days, whereas P. acidilactici did not further enhance the protective effect of the two former agents. Therefore, the combined treatment of PgAFP and D. hansenii seems to provide a promising protective mean against aflatoxin-producing A. parasiticus on dry-fermented foods.

Aflatoxin contamination in nuts marketed in Italy: preliminary results.

Aflatoxins (AFs) are one of the main groups of mycotoxins produced by molds. Nuts, although recognized as a food with health benefits, are frequently contaminated by AFs. In this preliminary study we evaluated the contamination by total AFs and AFB1 in different types of nuts from different countries marketed in Apulia. Overall, 124 samples (almonds, apricot kernels, chestnuts, hazelnuts, peanuts, pistachios, walnuts and Brazil nut) were analyzed using an High-Performance Liquid Chromatography system. Twenty samples (16.1%) were contaminated with AFs of which 55% were non-compliant, according to Reg. 165/2010. The median values (µg/kg) of total AFs and AFB1 were 16.6 and 15.1, respectively. Pistachios appeared more susceptible to AF contamination than the other nuts, with levels of total AFs ranging from 8.8 to 387.3 µg/kg and of AFB1 from 8.2 to 354.5 µg/kg. The majority of contaminated samples came from Asia and AF contamination was different in the various Asiatic sub-regions: regardless of the type of nuts, samples from Western Asia were the least contaminated. As geographical origin may influence the risk of contamination, in order to protect human health, customer countries should increase AF monitoring in nuts coming from those countries with favorable environments for the growth of aflatoxigenic molds or with less strict regulations.

The growth and aflatoxin production of Aspergillus flavus strains on a cheese model system are influenced by physicochemical factors

Traditional cheeses may be contaminated by aflatoxin-producing Aspergillus flavus during the ripening process, which has not been sufficiently taken into account. The objectives of this study were to evaluate the influence of water activity (aw), pH, and temperature on the lag phases, growth, and aflatoxin production of 3 A. flavus strains (CQ7, CQ8, and CG103) on a cheese-based medium. The results showed that the behavior of A. flavus strains was influenced by pH, aw, and temperature conditions. The CQ7 strain showed the maximum growth at pH 5.5, 0.99 aw, and 25°C, whereas for CQ8 and CQ103 strains, no differences were obtained at pH 5.5 and 6.0. In general, low pH, aw, and temperature values increased the latency times and decreased the growth rate and colony diameter, although aw and temperature were the most limiting factors. Maximum aflatoxin production on the cheese-based medium occurred at pH 5.0, 0.95 aw, and 25 or 30°C, depending on the strain. This study shows the effect of pH, aw, and temperature factors on growth and aflatoxin production of 3 aflatoxigenic A. flavus strains on a cheese-based medium. The findings may help to design control strategies during the cheesemaking process and storage, to prevent and avoid aflatoxin contamination by aflatoxigenic molds.

Quantitative proteomics reveals new insights into calcium-mediated resistance mechanisms in Aspergillus flavus against the antifungal protein PgAFP in cheese

The ability of Aspergillus flavus to produce aflatoxins in dairy products presents a potential hazard. The antifungal protein PgAFP from Penicillium chrysogenum inhibits various foodborne toxigenic fungi, including Aspergillus flavus. However, PgAFP did not inhibit A. flavus growth in cheese, which was related to the associated cation content. CaCl2 increased A. flavus permeability and prevented PgAFP-mediated inhibition in potato dextrose broth (PDB). PgAFP did not elicit any additional increase in permeability of CaCl2-incubated A. flavus. Furthermore, PgAFP did not alter metabolic capability, chitin deposition, or hyphal viability of A. flavus grown with CaCl2. Comparative proteomic analysis after PgAFP treatment of A. flavus in calcium-enriched PDB revealed increased abundance of 125 proteins, including oxidative stress-related proteins, as determined by label-free mass spectrometry (MS)-based proteomics. Seventy proteins were found at lower abundance, with most involved in metabolic pathways and biosynthesis of secondary metabolites. These changes do not support the blockage of potential PgAFP receptors in A. flavus by calcium as the main cause of the protective role. A. flavus resistance appears to be mediated by calcineurin, G-protein, and γ-glutamyltranspeptidase that combat oxidative stress and impede apoptosis. These findings could serve to design strategies to improve PgAFP activity against aflatoxigenic moulds in dairy products.

Analysis of aflatoxin B1 and aflatoxigenic mold in commercial poultry feeds in Tamil Nadu, India

A total of 48 commercial poultry feed samples collected from different poultry feed manufactures in Tamil Nadu, India were examined for the contamination of aflatoxin B1 (AFB1) and Aspergillus flavus. AFB1 in the samples was estimated by sandwich ELISA and the presence of A. flavus was detected by Real-Time PCR assay. Real-Time PCR analysis using A. flavus- specific omt primers confirmed the presence of A. flavus in all the samples tested. ELISA results indicated that the AFB1 contents in the poultry feeds ranged from 1.0 to18.7 ppb, which were below the permissible safe limits for poultry bird consumption and health. The results suggest adoption of good man-ufacturing practices by the commercial poultry feed manufacturers during procurement of feed ingredients, handling, storage and processing which might have suppressed the growth of A. flavus and aflatoxin contamination.