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A new reliable, fast, and simple method for the detection of aflatoxigenic Aspergillus strains, consisting of the addition of a cyclodextrin (a methylated ␤-cyclodextrin derivative) to common media used for testing mycotoxin production ability, was developed. We propose the use of this compound as an additive for fungal culture media to enhance the natural fluorescence of aflatoxins. The production of aflatoxins coincided with the presence of a bright blue or blue-green fluorescent area surrounding colonies when observed under longwavelength (365-nm) UV light after 3 days of incubation at 28°C. The presence of aflatoxins was confirmed by extracting the medium with chloroform and examining the extracts by high-pressure liquid chromatography with fluorescence detection.Aflatoxins are mycotoxins with highly toxic and carcinogenic properties produced by some strains of Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius. These fungi are frequently found in foodstuffs and animal feeds. However, not all strains are able to produce aflatoxins, and this has encouraged the use of screening for their aflatoxin production abilities. The methodology commonly used for this survey involves the culture of strains in a suitable liquid or solid medium and their later extraction and analysis for the presence of aflatoxins by chromatographic techniques. Yeast extract-sucrose (YES) medium (3) and natural media with wheat, rice, or peanut (9) have been used for this purpose. Testing large numbers of isolates on a variety of substrates with this procedure is tedious and time-consuming. For this reason, several screening methods for direct visual determination of aflatoxin production have been developed. These methods use more or less complicated culture media containing additives to enhance the production of aflatoxins in order to achieve direct visual determination of a bright blue or blue-green fluorescent area surrounding colonies under UV radiation. Thus, a complex agar medium containing sucrose, various salts, and an aqueous extract of aflatoxin-free peanuts (5); a modified Czapek agar medium containing corn steep liquor, named aflatoxin-producing ability (APA) medium (9); media containing coconut, named coconut agar medium (4, 13), coconut extract agar (11,12), and coconut cream agar (6); the synthetic liquid medium of Adye and Mateles (1); and a silica gel medium (15) are currently in use.The natural fluorescence of aflatoxins arises from their oxygenated pentaheterocyclic structure. The cyclodextrins (cyd) are molecules formed by the action of the enzyme cyd-transglycolase on dextrans and have different sizes [they contain from six to eight units of glucose in an ␣(1-4) configuration, according to which they are called ␣-, ␤-, or ␥-cyd]. They are available commercially, and their physical and chemical properties have been described in the literature (14). These oligomers are able to include a large number of organic and inorganic species in their cavities, and in this work, excitation of the natural fluorescen...

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A modified beef hamburger patty enriched in polyunsaturated n−3 fatty acids and α-tocopherol was developed using technological procedures. Raw meat was obtained from low-cost parts of beef carcasses (brisket and flank) to which visible fat and connective tissue was manually eliminated and substituted by a mixture of preemulsified olive, corn, and deodorized fish oil. The developed product was analyzed and compared to conventional beef hamburger patties for their proximate composition, fatty acid profile, and consumer acceptability. The effects of cooking on the fat content and fatty acid profile of the developed product were investigated. Additionally, the lipid oxidation and surface color stability of modified and conventional hamburgers were investigated during 8 days of refrigerated storage while packaged in a modified atmosphere (20%/80% CO 2 /O 2 ) and subsequently cooking. The developed product showed significantly lower total fat, cholesterol, sodium, and calorie content than beef hamburger patties manufactured using conventional procedures. In addition, the polyunsaturated fatty acids/saturated fatty acids and n−6/n−3 ratios matched nutritional recommendations more closely. No evidence of lipid oxidation was found for the modified hamburger patties during 8-day storage period, and surface color, especially redness, was more stable than in conventional ones. Additionally, consumer acceptability of the developed patty after it was cooked was acceptable and similar to that of conventional products. The modified hamburger patty developed by technological methods is viable and can be considered a useful food to preclude nutritional disorders or to assist in nutritional regimens.

The aim of this study was to determine the effect of different cooking processes (microwaving, roasting, boiling, grilling and frying) on naturally incurred enrofloxacin residues in chicken muscle. Enrofloxacin and its metabolite, ciprofloxacin, were analysed using a validated LC-MS method with limits of detection (LOD) and quantification (LOQ), respectively, of 2 and 5 ng g-1 quinolones in muscle samples. The method was shown to be linear over the range 5-500 ng g-1. Mean intra-day relative standard deviation (RSD) at a concentration of 50 ng g-1 (n = 6) was 6%; inter-day RSD was 12%. A recovery study demonstrated that 65-101%, of the drug and metabolite could be recovered from the tissue. The RSD with naturally incurred roasted chicken breast was 9.18% at a concentration of 11 +/- 1.01 ng g-1 (n = 6). In water, enrofloxacin remained stable for 3 h when heated at 100 degrees C. It was concluded that residue data from raw tissue are valid for estimation of consumer exposure to this drug, as well as the ADI calculations because cooking procedures did not affect enrofloxacin residues, which remained stable during heating. However, there was an apparent decrease in quinolone concentration in tissue because some was lost by exudation into the liquid used for cooking. Conversely, for a cooking procedure with water loss, there was an apparent increase in residue concentration.

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