Effect of yearly conditions and management practices on ochratoxin A production in Sultana Seedless vineyards.

Sun drying of seedless grapes (Vitis vinifera cv. Sultanina) is widely practised in the western Aegean Region providing Turkey with a significant share in the world trade of sultanas. Research was initiated in 1998 to determine the incidence of ochratoxin A (OTA), to identify the major factors resulting in contamination and to develop techniques to reduce or prevent contamination. This paper assesses OTA formation in five experimental vineyards located in Manisa province of Turkey between 1998 and 2003. The cultural practices recorded were tillage (type and timing), fertilisation, plant protection, irrigation, trellising, pruning, GA(3) application, harvest maturity and date, and drying practices (type of drying yard, dipping into alkaline solution, length of drying period). In the experimental vineyards, no OTA was found at veraison. OTA levels in grapes harvested at fresh maturity ranged between

Phosphate uptake performance of bacteria isolated from a full-scale Izmir municipal wastewater treatment plant.

This study investigated the phosphate uptake capacities of bacteria isolated from aerobic and anaerobic phosphate removal tanks at a municipal wastewater treatment plant in Izmir, Turkey, removing chemical oxygen demand to nitrogen (COD-N) and phosphorus (P) on a full-scale basis. Conventional plating techniques and an enrichment culture method were used to isolate the colonies, with a total of 91 monoculture isolates from the sludge samples being subjected to phosphate uptake studies. A total of 64 of these isolates had high phosphate uptake capacities ranging from 3.7 x 10(10) to 1.0 x 10(-12) mg PO4(3-) cell(-1), and only 11 of the strains with high phosphate uptake were Gram-negative. The highest phosphorus uptake value was 3.7 x 10(-10) mg PO4(-3) cell(-1), which was achieved by Gram-positive bacteria. Gram-negative strains were identified as Acinetobacter baumannii with a 99% probability and as Pseudomonas aeruginosa with a 96-98% probability (API 20 NE).

Five-year survey of ochratoxin A in processed sultanas from Turkey.

The results of surveillance for ochratoxin A (OTA) in 1885 samples of sultanas taken during five crop years between 1999 and 2003 are reported. The analytical method was based on extraction with methanol + sodium bicarbonate and clean-up by immunoaffinity column chromatography followed by high-performance liquid chromatography with fluorescence detection. The limit of detection for OTA was 0.3 microg kg(-1). The results show that 9.3% of the samples contained no detectable levels of OTA, whereas 0.6% had concentrations exceeding 10 microg kg(-1); the remaining 90.3% had levels within the range 0.3-10 microg kg(-1). The overall mean OTA concentration in the total number of 1885 samples taken was 1.36 +/- 2.91 microg kg(-1); the overall median was calculated as 0.90 microg kg(-1).

Ochratoxin A in sultanas from Turkey I: Survey of unprocessed sultanas from vineyards and packing-houses.

A method for the determination of ochratoxin A (OTA) in sultanas from Turkey using extraction with a sodium bicarbonate solution (2% NaHCO3) followed by immunoaffinity clean-up and liquid chromatography with fluorescence detection was used to assess the frequency of occurrence and level of OTA. In-house validation was carried out with spiked samples at levels of 0.15, 1.5, 5.0 and 10 microg kg-1 and average recoveries were 91, 93, 87 and 89%, respectively. The limits of detection and limit of quantification in Turkish sultanas were 0.026 and 0.09 microg kg-1, respectively. A survey for the presence of OTA was carried out on 264 unprocessed sultana samples during the production seasons between 1998 and 2000 collected annually from vineyards and from packing-houses. The analyses of unprocessed sultanas showed that 32.2% of the total number of samples contained no detectable OTA, whereas 9.8% of sultana samples had OTA concentrations above 10 microg kg-1, and the remaining 58% had levels within the range 0.026-10 microg kg-1. There were big differences in median concentrations between years. Considering the year of production, it appears that sultanas produced in 1998 and 2000 showed the lowest incidence of OTA contamination (median<0.02 microg kg-1), whereas 2002 showed the highest incidence (median=4.3 microg kg-1). The overall mean OTA concentration was calculated as 3.4 microg kg-1, and the overall median as 0.9 microg kg-1. Among the samples analysed, the highest detected level of OTA was 54 microg kg-1.

Growth and aflatoxin B1 production on olives and olive paste by moulds isolated from 'Turkish-style' natural black olives in brine.

The growth and aflatoxin production of five Aspergillus flavus and two Aspergillus parasiticus strains isolated from natural black olives in brine for table consumption, fresh whole black olives, fresh damaged black olives and fresh black olive paste were examined. Aspergillus flavus NRRL 6555 and A. parasiticus NRRL 2999 strains were also studied for comparison. All aflatoxigenic strains inoculated onto fresh damaged black olives and fresh black olive paste grew extensively but on fresh whole black olives they grew weakly. Strong aflatoxigenic strains produced low levels of aflatoxins on fresh whole black olives, fresh damaged black olives and fresh black olive paste. Weak aflatoxigenic strains did not produce detectable amounts of aflatoxin.

Permeability of protective gloves used in dental practice.

Two brands of latex rubber gloves and one brand of polyvinyl chloride glove were examined for their permeability. New and used gloves were included. All of the gloves were examined visually and then subjected to an air leakage test, an electrical test, and a microbiologic test. Permeability was evaluated independently by two researchers in a blind manner. Statistical analysis showed that there were no significant differences among the three brands of gloves or with respect to the usage periods, according to visual inspection and the air leakage test. Conversely, there were significant differences among each of the three brands of gloves and with respect to usage periods, according to the electrical and microbiologic tests.