M Marija Skrinjar

Real and Perceived Risks for Mycotoxin Contamination in Foods and Feeds: Challenges for Food Safety Control

Mycotoxins are toxic compounds, produced by the secondary metabolism of toxigenic moulds in the Aspergillus, Alternaria, Claviceps, Fusarium, Penicillium and Stachybotrys genera occurring in food and feed commodities both pre- and post-harvest. Adverse human health effects from the consumption of mycotoxins have occurred for many centuries. When ingested, mycotoxins may cause a mycotoxicosis which can result in an acute or chronic disease episode. Chronic conditions have a much greater impact, numerically, on human health in general, and induce diverse and powerful toxic effects in test systems: some are carcinogenic, mutagenic, teratogenic, estrogenic, hemorrhagic, immunotoxic, nephrotoxic, hepatotoxic, dermotoxic and neurotoxic. Although mycotoxin contamination of agricultural products still occurs in the developed world, the application of modern agricultural practices and the presence of a legislatively regulated food processing and marketing system have greatly reduced mycotoxin exposure in these populations. However, in developing countries, where climatic and crop storage conditions are frequently conducive to fungal growth and mycotoxin production, much of the population relies on subsistence farming or on unregulated local markets. Therefore both producers and governmental control authorities are directing their efforts toward the implementation of a correct and reliable evaluation of the real status of contamination of a lot of food commodity and, consequently, of the impact of mycotoxins on human and animal health.

ANTIMICROBIAL EFFECTS OF SPICES AND HERBS ESSENTIAL OILS

Spices and herbs have been used as food additives since ancient times, as flavouring agents but also as natural food preservatives. A number of spices shows antimicrobial activity against different types of microorganisms. This article gives a literature review of recent investigations considering antimicrobial activity of essential oils widely used spices and herbs, such as garlic, mustard, cinnamon, cumin, clove, bay, thyme, basil, oregano, pepper, ginger, sage, rosemary etc., against most common bacteria and fungi that contaminate food (Listeria spp., Staphylococcus spp., Salmonella spp., Escherichia spp., Pseudomonas spp., Aspergillus spp., Cladosporium spp. and many others). Antimicrobial activity depends on the type of spice or herb, type of food and microorganism, as well as on the chemical composition and content of extracts and essential oils. Summarizing results of different investigations, relative antimicrobial effectiveness can be made, and it shows that cinnamon, cloves and mustrad have very strong antimicrobial potential, cumin, oregano, sage, thyme and rosemary show medium inhibitory effect, and spices such as pepper and ginger have weak inhibitory effect.

The Overview on Toxigenic Fungi and Mycotoxins in Serbia and Montenegro

The available literature data indicate that the importance of toxigenic fungi and mycotoxins is much greater for the area of Serbia than for the area Montenegro. The knowledge on the occurrence of moulds (Gibberella saubinetii), as well as on animal and human diseases caused by mouldy food, especially by maize that has been traditionally grown as food and feed in the area of Serbia, dates as far back as the 19th and the beginning of the 20th century (Radic, 1872; Lozanie, 1904; Ranojevie, 1914). However, the largest outbreaks of epidemic moulds, mostly caused by Fusarium species, were registered in maize in 1955, 1968, 1972, 1974 and 1984 and in wheat in the early 1970s (Levic, 2004). The greatest outbreaks of animal diseases, especially diseases of pigs such as oestrogenism, vomiting and feed refusal, dermatoxicity, haemorrhages and others were recorded during the same and/or subsequent years. Alimentary intoxication of horses, described in some cases in 1955, indicates, to a great extent, clinical signs of eleucoencephalomalacia. This type of horse illness could be a result of the use of mouldy feedstuffs, mostly husked maize ears and shelled kernels (Raj ic, 1963), or of the occurrence of F. monilifoorme that prevailed in epidemic ear rot in 1955 (Marie, 1981). Nevertheless, it has never been completely observed nor identified.

Decrease of aflatoxin B1 in yoghurt and acidified milks

Fermentation of yoghurt and acidified milks containing aflatoxin B1 (AB1) were studied. AB1 added to milk before fermentation at concentrations of 600, 1000 and 1400 μg/kg was reduced in yoghurts (pH 4.0) by 97, 91 and 90%, respectively. Coagulation time was approximately the same as in the controls. Streptococci had longer chains than those in the controls. The main decrease of AB1 occurred during the milk fermentation. A decrease of AB1 (conc. 1000 μg/kg) in milks acidified with citric, lactic and acetic acids (pH 4.0) was 90, 84 and 73%, respectively.

Effect of mint (Mentha piperita L.) and caraway (Carum carvi L.) on the growth of some toxigenic aspergillus species and aflatoxin B1 production

An inhibitory effect of various concentrations (0.0, 0.5, 1.0, 1.5 and 2,0%) of mint (Mentha piperita L.) and caraway (Carvum carvi L.) on the growth of A. fumigatus, A. flavus and A. ochraceus was examined during 10 days of cultivation in YES medium at temperature of 25°C. Mint showed stronger inhibitory effect than caraway. Total dry weight (g/l) after 10 days of the growth of A. fumigatus in YES medium with 0.5% of mint decreased by about 95%, A. flavus by 97% and A. ochraceus by about 82%. Addition of higher concentrations of mint (1.0, 1.5 and 2.0%) reduced the growth of all tested species. It was poor and hardly visible. pH values of the media increased with the increase of mint concentrations. A. fumigatus showed the highest sensitivity towards caraway and A. flavus the lowest. Total dry weight (g/l) after 10 days of growth of A. fumigatus in medium with 0.5% of caraway decreased by about 72% in comparison to the control. In media with higher concentrations of caraway, its growth was found to be very poor. Concentration of 1.0% of caraway reduced A. flavus growth by 15% and of 1.5% by 92%, in regard to the control. In medium with 2.0% of caraway the growth of A. flavus was observed as poor and hardly visible. The growth of A. ochraceus in medium with 0.5% of caraway decreased by about 85% comparing with control and further decrease was noticed by the increase of concentrations. In medium with 1.5% of caraway a reduction of about 95% of growth was found and under 2.0% of caraway it was poor. pH of the media also increased with the increase of caraway concentrations. Applied concentrations of mint and caraway inhibited completely the production of AB1 by A. flavus.

Alternaria toxins in wheat from the Autonomous Province of Vojvodina, Serbia: a preliminary survey

Although Fusarium species remain a main source of mycotoxin contamination of wheat, in recent years, due to the evident climatic changes, other mycotoxigenic fungi have been recognised as important wheat contaminants. Alternaria species, especially A. alternata, have been found as contaminants of wheat as well as wheat-based products. Under favourable conditions A. alternata very often produce alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA) and others Alternaria toxins. The aim of the present study was to examine the presence of three Alternaria toxins (AOH, AME and TeA) in wheat samples harvested during three years (2011–13). To this end, 92 samples were collected during wheat harvesting from different growing regions of the Autonomous Province of Vojvodina, which represents the most important wheat-growing area in Serbia. The presence of Alternaria toxins was analysed by HPLC with electrospray ionisation triple quadrupole mass spectrometry (LC-ESI-MS/MS). Among all the analysed wheat samples, 63 (68.5%) were contaminated with TeA, 11 (12.0%) with AOH and 6 (6.5%) with AME. Furthermore, the maximum and mean toxin concentrations were 2676 and 92.4 µg kg−1, 48.9 and 18.6 µg kg−1, and 70.2 and 39.0 µg kg−1 for TeA, AOH and AME, respectively. Co-occurrence of three Alternaria toxins in wheat samples was detected in six samples; a combination of two toxins was found in two samples; and 64 samples contained one toxin. The results showed that among 92 analysed wheat samples, only 20 (21.7%) samples were without Alternaria toxins. The presence of Alternaria toxins was also investigated in terms of weather conditions recorded during the period of investigation, as well as with the sampling region. This study represents the first preliminary report of the natural occurrence of Alternaria toxins in wheat (Triticum aestivum) from Serbia.

Presence of aflatoxins in cereals from Serbia

Aflatoxins (AFs), one of the most toxic and the strongest natural carcinogens can be found in a variety of food commodities, including cereals. For that purpose, the aim of this study was to investigate occurrence of AFs (AFB1, AFG1, AFB2 and AFG2) in 130 cereal samples. AFs content was determined by direct competitive Enzyme Linked Immunosorbent Assay (ELISA) method. Samples with AFs content higher than 1 μg/kg were analyzed again with confirmatory High Performance Liquid Chromatography with fluorescence detection (HPLC-FLD). Analyses showed that none of the analyzed wheat (30), barley (20), oats (20) and rye (20) samples was contaminated with AFs. On the other hand, among 40 analyzed maize samples 24 of them (60%) were contaminated in the following way: 6 (25%) samples had AFs concentration between 1 and 10 μg/kg, 14 (58%) samples between 10 and 50 μg/kg and 4 (17%) between 50 and 70.3 μg/kg. The most predominant aflatoxin was AFB1 which was detected in all contaminated maize samples. AFG1, AFB2 and AFG2 were found in 12, 5 and 1 sample, respectively. This study represents the first investigation of the occurrence of AFs in five different cereals from Serbia.

Effect of Origanum heracleoticum L. essential oil on food-borne Penicillium aurantiogriseum and Penicilium chrysogenum isolates

Molds are ubiquitously distributed in nature and their spores can be found in the atmosphere even at high altitudes. The difficulty of controlling these undesirable molds, as well as the growing interest of the consumers in natural products, have been forcing the industry to find new alternatives for food preservation. The modern trends in nutrition suggest the limitation of synthetic food additives or substitution with natural ones. Aromatic herbs are probably the most important source of natural antimicrobial agents. Origanum heracleoticum L. essential oil has been known as an interesting source of antimicrobial compounds to be applied in food preservation. In the this work, we have investigated the effect of essential oil obtained from O. heracleoticum on growth of six isolates of Penicillium aurantiogriseum and four isolates of Penicillium chrysogenum isolated from meat plant for traditional Petrovacka sausage (Petrovska klobasa) production. The findings reveal that the essential oil of O. heracleoticum provides inhibition of all of fungal isolates tested. O. heracleoticum L. essential oil exhibited higher antifungal activity against the isolates of P. chrysogenum than the isolates of P. aurantiogriseum. O. heracleoticum essential oil showed a MIC value ranging from 25 to 100 μL/mL. The fungi cultivated in the medium with higher concentration of essential oil showed certain morphological changes. The alterations included lack of sporulation and loss of pigmentation.

Antimicrobial properties of indigenous Lactobacillus sakei strain

The strain I 154 of Lactobacillus sakei has been isolated from traditionally fermented sausages in the course of the realization of the international project (INCO PROJECT No ICA4-CT-2002-10037). This strain exhibited the ability for bacteriocin production. Antimicrobial properties of the isolated bacteriocin (sakacine), its sensibility towards proteolytic enzymes, as well as the effect of increased to high temperatures on its stability have been examined in this work. Semi purified bacteriocin (sakacine) has been isolated from bacteriocin - producing strain Lactobacillus sakei I 154 by the method of saturated precipitation with up to 70% ammonium mono-sulphate solution. The activity of isolated sakacine was examined towards Listeria monocytogenes, Staphylococcus aureus and Escherichia coli 0157:H7. Pepsine, Papaine and Proteinase K were used as proteolytic enzymes. The influence of increased and high temperatures on the bacteriocin activity was examined at different temperatures and exposition periods including autoclaving effects.

Mycopopulations of grain and flour of wheat, corn and buckwheat

According to the nutritive characteristics, whole grain flour is a high quality product, due to its high vitamin, mineral, and dietary fiber content. However, the cereal grains are susceptible to the series of contamination during the ripening, harvesting, processing and storage. The aim of this work was to determine mold presence in grains and flour of wheat, corn and buckwheat. The determination of total number and identification of isolated genera and species of molds were the subject of this research. All samples were contaminated with the molds. The total number of molds per 100 cereal grains was between 60 cfu (wheat) and 120 cfu (buckwheat). The total number of molds in the samples of flour ranged from 6.0x10 cfu/g in white wheat flour to 5.0 x10 cfu/g in buckwheat whole grain flour (DG18 medium). Eight fungal genera (Alternaria, Aspergillus, Cladosporium, Chrysonilia, Fusarium, Penicillium, Rhizopus and Scopulariopsis) and fifteen species were isolated. The largest number of species of molds was isolated from the genus Aspergillus. About 66.7% of isolated fungi belonged to potentially toxigenic species. The results pointed out the necessity of grain surface treatment, preceding the milling of grains in wheat, corn and whole grain buckwheat flour production.