INCIDENCE OF TOXIGENIC MOULDS IN FOOD SPICES SOLD IN OPEN MARKETS IN BENIN CITY, NIGERIA

Spices are parts of plants or plant substances primarily used for flavouring and preservation of food. Spices can be exposed to microbial contamination and toxic substances such as mycotoxins during processing storage and distribution. The aim of the study was to determine the incidence of toxigenic moulds in food spices sold in open markets in Benin City. A total of 35 samples were obtained from three markets. Potato dextrose agar (PDA) and Aspergillus flavus and parasiticus agar (AFPA) were employed for the isolation, characterization and identification of fungal isolates using standard microbiological procedures. The pH was determined using an electronic pH meter, titratable acidity and moisture content were also determined using appropriate methods. Fungi isolated in this study included; Fusarium sp., Alternaria sp., Rhizopus sp., Geotrichum sp., Cladosporium sp., Aspergillus niger and Penicillium sp. The most occurring fungus was Fusarium sp. (26%) while Alternaria sp. (2%) was the least occurring fungus. The fungal load ranged from 0.33 - 28.67 x 103 sfu/g and the pH values of samples ranged from 4.83 – 5.67. The titratable acidity ranged from 0.037 – 0.521 mg/l, while the moisture content ranged from 2.0 – 28.0%. The study revealed the presence of toxigenic moulds such as Fusarium and Penicillium species in food spices sold in open markets. This may have resulted from improper storage, handling and poor sanitary conditions in the open markets.

Development of a Methodology for Estimating the Ergosterol in Meat Product-Borne Toxigenic Moulds to Evaluate Antifungal Agents

Antifungal agents are commonly used in the meat industry to prevent the growth of unwanted moulds, such as toxigenic ones, on dry-cured meat products. For enhancing the application of antifungals, their mode of action must be evaluated. Their effect on the mould ergosterol content is one of the most studied ones, since it is the target site of some commercialised antifungals or of those that are in development. The aim of this study was to develop a methodology for determining how the antifungal agents used in the meat industry work. A method for analysing ergosterol was firstly developed using high-performance liquid chromatography with fluorescence detection coupled to a diode array detector (HPLC-FLD/DAD). The chromatographically optimised conditions (gradient and mobile phases) allowed us to reduce the time per analysis with respect to previously published methods up to 22 min. Withing the six checked extraction methods, method 5, showing the best mean recovery values (99.51%), the shortest retention time (15.8 min), and the lowest standard deviation values (9.92) and working temperature (60 °C), was selected. The limit of detection and limit of quantification were 0.03 and 0.1 µg/mL, respectively. All the validation parameters corroborated the method’s suitability. Finally, its feasibility for evaluating the effect of a commercial antifungal preparation (AP) and different herbs that are frequently added to meat products on the ergosterol content of several toxigenic moulds was studied. Differences at the strain level were obtained in the presence of AP. Moreover, the addition of herbs significantly reduced the ergosterol content in Penicillium nordicum up to 83.91%. The developed methodology is thus suitable for screening the antifungals’ role in altering mould ergosterol biosynthesis before their application in real meat products.

Selection and Evaluation of Staphylococcus xylosus as a Biocontrol Agent against Toxigenic Moulds in a Dry-Cured Ham Model System

Toxigenic moulds can develop on the surface of dry-cured meat products during ripening due to their ecological conditions, which constitutes a risk for consumers. A promising strategy to control this hazard is the use of antifungal microorganisms usually found in these foods. However, to date, the effectiveness of gram-positive catalase-positive cocci (GCC+) has not been explored. The aim of this work was to select GCC+ isolates with antifungal activity to study its effectiveness in a dry-cured ham model system at the environmental conditions reached during the ripening. Forty-five strains of GCC+ were evaluated and the isolate Staphylococcus xylosus Sx8 was selected to assess its efficacy at two different concentrations (106 and 104 cfu/mL) against Penicillium nordicum, Aspergillus flavus, Aspergillus parasiticus, and Penicillium griseofulvum at 15, 20, and 25 °C. The results showed that the inoculation of 106 cfu/mL of S. xylosus completely inhibited the growth of most fungi. In addition, in the presence of this strain at 104 cfu/mL, a significant reduction in fungal growth and mycotoxins production was observed at the three temperatures studied. In conclusion, S. xylosus Sx8 possesses great potential as a biological agent to control toxigenic moulds in dry-cured meat products.

Influence of ecophysiological factors on the presence of ochratoxin A in dried vine fruits: A review

Grapes derived products, especially dried vine fruits (raisins, sultanas, currants), are very often used in human nutrition, and along with wine, are of significant economic importance in Mediterranean countries, especially in Spain, Greece, Turkey and Italy. The diversity of climate in the areas where grape is grown, indicate that moulds, potential producers of ochratoxin A (OTA), are ubiquitously distributed. Considering this fact, OTA itself is commonly isolated from these products. Great efforts are taken to eliminate ochratoxigenic moulds and preform detoxification of the products, but efficient methods have not been found so far. Because of that, the inhibition of mould growth is of great importance. It is well known that the ecophysiological factors highly influence the presence of toxigenic moulds in different food products, including production of OTA. The aim of this work was therefore to summarize results obtained so far on the presence of OTA in dried vine fruit, and to outline the influence of ecophysiological factors on mould and OTA presence in this commodity.

Mycological and mycotoxicological analysis of a herb (oregano) used in meat industry

Raw materials used in meat industry can be contaminated with toxigenic moulds and mycotoxins. Such raw materials present a source of contamination of final products with these compounds. This paper gives a review of the presence of aflatoxin B1, ochratoxin A and zearalenon and moulds in five different samples of oregano.