Nigella sativa oil: A promising prospective antifungal agent in the manufacture of low-salt soft cheese

The current work studied the in-vivo antifungal activity of Nigella sativa oil (NSO) in ultrafiltered low-salt soft cheese as a proposed replacement for the synthetic preservatives which become unacceptable by consumers. Four different concentrations of NSO were examined during the manufacture of the cheese (0.3, 0.5, 1, and 3 % w/w). The effect of NSO supplementation was examined in 3 parallel lines; a ninepoint hedonic scale was used in the sensorial evaluation of soft cheese free of the fungal inoculum, the physicochemical properties of soft cheese were determined during storage as well as anti-fungal effects of different concentrations of NSO on inoculated cheese with different species of fungi: Candida albicans (104 cfu/ml) and Aspergillus parasiticus (102 cfu/ml) before coagulation. The Nigella sativa oil expressed an antifungal activity by using different levels of NSO which significantly reduced and inhibited the growth of the fungal counts (1.4 log cfu/g for Candida albicans and 2.30 log cfu/g for Aspergillus parasiticus) started from 0.5% concentration of NSO on the 14th day of the storage. In addition, it exhibited different physicochemical properties of soft cheese depending on the level of used NSO. However, the Sensory evaluation of cheese samples revealed the acceptance of soft cheese samples with 0.3% and 0.5% of NSO.

Advances in the Total Synthesis of Aflatoxins

Aflatoxins, which are produced by Aspergillus flavus, Aspergillus nomius, and Aspergillus parasiticus, are a group of pentacyclic natural products with difuran and coumarin skeletons. They mainly include aflatoxin B1, B2, G1, G2, M1, and M2. Biologically, aflatoxins are of concern to human health as they can be present as contaminants in food products. The unique skeletons of aflatoxins and their risk to human health have led to the publication of nine remarkable total syntheses (including three asymmetric syntheses) and ten formal total syntheses (including four asymmetric formal syntheses) of aflatoxins in the past 55 years. To better understand the mechanism of the biological activity of aflatoxins and their presence in samples from the food industry, this review summarizes progress in the total synthesis of aflatoxins.

Toxigenic Species Aspergillus parasiticus Originating from Maize Kernels Grown in Serbia

In Serbia, aspergillus ear rot caused by the disease pathogen Aspergillus parasiticus (A. parasiticus) was first detected in 2012 under both field and storage conditions. Global climate shifts, primarily warming, favour the contamination of maize with aflatoxins in temperate climates, including Serbia. A five-year study (2012–2016) comprising of 46 A. parasiticus strains isolated from maize kernels was performed to observe the morphological, molecular, pathogenic, and toxigenic traits of this pathogen. The HPLC method was applied to evaluate mycotoxin concentrations in this causal agent. The A. parasiticus isolates synthesised mainly aflatoxin AFB1 (84.78%). The percentage of isolates synthesising aflatoxin AFG1 (15.22%) was considerably lower. Furthermore, the concentration of AFG1 was higher than that of AFB1 in eight isolates. The polyphase approach, used to characterise isolates, showed that they were A. parasiticus species. This identification was verified by the multiplex RLFP-PCR detection method with the use of restriction enzymes. These results form an excellent baseline for further studies with the aim of application in the production, processing, and storage of cereal grains and seeds, and in technological processes to ensure the safe production of food and feed.

Chemical composition and antifungal activity of oil extracted from leaves turmeric (Curcuma longa)

Turmeric rhizomes are commonly used in the culinary, pharmaceutical, herbal medicine, and beverage industries. On the contrary, turmeric leaves are underutilized. The aims of this study were to extract the essential oil from turmeric leaves, characterize the chemical composition of the oil, and determine its antifungal activities against aflatoxin-producing fungi. Steam distillation was used to extract the essential oil from turmeric leaves. The properties of the oil were identified using GC-MS. Antimicrobial activities against Aspergillus flavus and Aspergillus parasiticus were determined. Spores of the fungi were inoculated into potato dextrose agar plates supplemented with various quantities of turmeric leaves essential oil and incubated at 30°C for 7 days. The oil's primary constituents were α-phelandrene(46.70 %), followed by α-terpinolene (17.39 %), 1,8-cineole (8.78 %), benzene (4.24 %), and 2-β pinene (3.64 %). At low (<1%) concentrations, the oil delayed mycelia formation and at high concentrations it significantly inhibit fungal growth (at 1%) and completely inhibit colony formation (at 2%) Additionally, the result show that turmeric leaves oil can inhibited fungus growth at the lowest concentration (0.25 %) when compared to the control over a seven-day incubation period.

Combinational inhibitory action of essential oils and gamma irradiation for controlling Aspergillus flavus and Aspergillus parasiticus growth and their aflatoxins biosynthesis in vitro and in situ conditions

The purpose of this study was to investigate the effects of certain essential oils (star anise, lemon leaves, marjoram, fennel, and lavender) on the fungal growth of Aspergillus flavus and Aspergillus parasiticus and their production of aflatoxin B1 (AFB1). The degree of suppression of the aflatoxigenic strains’ growth and their production of AFB1 is mainly affected by the kind and the concentration of the tested essential oils (EOs). Star anise essential oil had the lowest minimum inhibitory concentration (0.5 and 1.0 μL/mL) against A. flavus and A. parasiticus, respectively, so it was the best among the five different oils. The study of liquid chromatography with tandem mass spectrometry revealed that star anise EO resulted in a 98% reduction in AFB1 without a breakdown of AFB1 products after treatment thus the complete removal of AFB1 was done without any toxic residues. The combination showed a synergistic effect, the combinational treatment between γ-irradiation at a low dose (2 kGy) and star anise EO at concentrate 0.5 μL/g destroyed A. flavus and A. parasiticus inoculated (individually) in sorghum and peanut, respectively throughout the storage period (8 weeks).

Identification and Characterisation of Seed-Borne Fungal Pathogens Associated with Maize (Zea mays L.)

A research study was conducted to identify and characterise seed-borne fungal pathogens associated with maize (Zea mays L.) in storage. Seed-borne fungal pathogenic infections of maize were studied using seed samples collected from Gokwe South District in Zimbabwe. The agar plating method using PDA medium was used to detect fungal pathogens on the maize seeds. A total of 150 treatments were used for this experiment, which were replicated three times in a randomised complete block design (RCBD). Analysis of the grain showed the presence of Fusarium moniliforme, Rhizopus stolonifer, Penicillium citrinum, and mostly Aspergillus species, namely, Aspergillus flavus, Aspergillus parasiticus, Aspergillus niger, and Aspergillus tamarii. Significant differences ( p < 0.05) between treatments were detected for the pathogens. A total of ten samples were used for mycotoxin determination, and all of them were 100% positive with aflatoxin total, zearalenone, fumonisin, and deoxynivalenol (DON) having an average of 0.255 ppb, 2.425 ppb, 2.65 ppb, and 0.07 ppb, respectively. The present study showed that most grain samples are contaminated with different species of fungi with mycotoxigenic potential. The data on the diversity and magnitude of pathogen infection by fungal species will have a significant effect even at the regional level for predicting the extent of pre- and postinfections. Measures to reduce mycotoxin contamination are needed for maize grains.

Prevalence of mould in chicken meat-cuts, giblets and products with immunoaffinity detection of aflatoxin residues

Mould contamination and aflatoxin residues are considered big problems in the food chain, therefore 140 random samples of frozen chicken breast, thigh, gizzard, heart, liver, chicken burger, and chicken luncheon (twenty of each) were examined for detection of mould contamination level there proteolytic and lipolytic activity and aflatoxin residues in examined products. Mould colonies were detected in 100% and 30% of samples with mean values of 3.42±0.71 and 1.29±0.30 log10CFU/g in the chicken burger and chicken luncheon, respectively. The identified species were Aspergillus 76/140 (54.3%), Penicillium 39/140 (27.9%), Alternaria 35/140 (25%), Cladosporium 30/140 (21.4%), Rhizopus13/140 (9.3%), Acremonium 10/140 (7.1%), Mucor 9/140 (6.4%), Fusarium 7/140 (5%) and Sporotricum 7/140 (5%). Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Aspergillus parasiticus, Aspergillus ochraceus and Aspergillus terrus were identified with total percentages of 53(37.9%), 25(17.9%), 21(15%), 5(3.5%), 5(3.5%) and 8(5.7%), respectively. The proteolytic and lipolytic activity detected in all species ranged between high, moderate and weak degrees except A. parasiticus shows only lipolytic activity. The examined samples had variable incidence and concentrations of aflatoxin residues as (20%) 1.49±0.53, (15%) 1.89±0.89, (55%) 8.79±14, (25%) 1.64±0.38, (20%) 2.3±0.72, (65%) 9.21±1.12 and (35%) 4.12±0.68 µg/ kg in frozen chicken breast, thigh, gizzard, heart, liver, chicken burger and chicken luncheon, respectively. Thus, strict hygienic measures during the production of chicken products must be adopted to minimize the deviation in their nutritional quality due to the growth of proteolytic and lipolytic mould, in addition, to protecting human health from the hazards of aflatoxin residues.