摘要:

Fumonisins, toxic metabolites of certain Fusarium molds, can be found in corn and corn‐based foods at levels sufficient to cause disease in livestock. Widely used methods of analysis involve organic extraction followed by isolation with either C18or strong anion exchange columns. An affinity column procedure that simultaneously isolated both intact and hydrolyzed fumonisins from corn is reported. The columns were prepared using two monoclonal antibodies with differing specificities, the first (P2A5–3‐F3) bound intact fumonisins, while the second (P2F11–3‐H7) bound their hydrolysis products. Corn samples were extracted with methanol/phosphate buffer (80:20, v:v) and the extract was diluted and applied to the affinity column. The recoveries of FB1from corn spiked with 0.5–8.0 ppm averaged 82%. The recoveries of HFB1over the range 0.25–1.25 ppm averaged 102%. Affinity columns capable of binding both intact and hydrolyzed fumonisins allow for the analysis of both types of toxins simultaneously from a single methanolic extract.

ISSN:0954-0105    

DOI:10.1080/09540109709354929

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Polyclonal antibodies were prepared against the fluoroquinolone sarafloxacin. Sarafloxacin was conjugated directly to cationized bovine serum albumin (BSA) and ovalbumin. Balb/c mice were immunized with the sarafloxacin‐BSA conjugate (cBSA‐saraflox) and sarafloxacin‐reactive sera (1–5) were obtained from these mice. Serum from mouse 1 (Abl) exhibited the lowest IC50for free sarafloxacin using an indirect competitive inhibition ELISA (ci‐ELISA). Other structurally related quinolones, including difloxacin, enrofloxacin, norfloxacin, trovafloxacin and nalidixic acid, demonstrated cross‐reactivity with the sarafloxacin antibodies as determined by ci‐ELISA. In an effort to correlate antibody binding with three‐dimensional properties of the cross‐reactive compounds, all of the fluoroquinolones as well as nalidixic acid were modeled, and global energy minima were determined using molecular mechanical and quantum mechanical methods. The results demonstrate that the three‐dimensional models can yield information that explains observed cross‐reactivity data. These models are particularly helpful when the chemical structure of an analog varies greatly from the immunogen yet the IC50value for the compound is not vastly different. Furthermore, conformational and electronic data from this study can be used to predict whether other fluoroquinolones will exhibit good cross‐reactivity in this ELISA.

ISSN:0954-0105    

DOI:10.1080/09540109709354930

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

An analytical method to detect the illegal application of anabolic steroids in cattle by hair analysis was developed. The time course of incorporation of the orally active xenobiotic steroids ethinyl‐oestradiol (EE2) and methyltestosterone (MT) into growing hair, the duration of their detection by hair analysis and the influence of hair pigmentation on steroid concentrations were investigated in detail. Female veal calves of different coat colour were fed with 3.5 μg of EE2 kg‐1of body weight and 35 μg of MT kg‐1of body weight, twice daily, for 10 days. Before, during and after treatment, hair samples were obtained and analyzed for EE2and MT residues. An appropriate method was developed to extract EE2and MT from hair. The extraction procedure consisted of liquid‐liquid and solid‐phase extraction and was followed by an essential high‐pressure liquid chromatography step for further purification of the extracts. The final quantification was carried out with specific enzyme immunoassays. EE2and MT residues could be detected in hair from day 4 (approximately 1 ng of EE2g‐1of hair and 5 ng of MT g‐1) of the experiment up to day 38 (approximately 0.3 ng of EE2g‐1) and day 94 (approximately 0.5 ng of MT g‐1) respectively. The plasma concentrations of MT during the treatment were about 10‐fold higher than the plasma concentrations of EE2. Steroid accumulation in hair seemed to depend on the plasma levels of the steroids applied because the accumulation of MT in hair was higher (approximately 7 ng g‐1) than the accumulation of EE2(approximately 1 ng g‐1). In addition, the tracking of MT by hair analysis was possible for a much longer duration (up to day 94 of the experiment) than the detection of EE2(day 38). There was no influence of pigmentation on the steroid concentrations in hair. These results suggest that hair analysis is a powerful means with which to detect and track the illegal use of anabolic steroids in animal production, horse‐racing and sports.

ISSN:0954-0105    

DOI:10.1080/09540109709354931

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Polyclonal antisera were raised to conarachin, the 7S globulin of peanut, Arachis hypogea. The antisera were of high titre and were specific for conarachin, showing no significant cross‐reaction with proteins from a range of nuts and legumes, as determined by immunoblotting and ELISA. A dipstick ELISA was developed using these antisera as both the capture and detector elements of the assay. The final steps utilized an avidin‐biotin detection system and tetramethylbenzidine as the substrate. The dipstick assay was highly sensitive, and employed a simple one‐step extraction method. It was able to detect as little as 0.01% (w/w) of peanut in marzipan and 0.1% (w/w) of peanut in chocolate. Roasted nuts were also detected, down to a concentration of 0.1% (w/w) in both foods. The dipstick assay also functioned with a range of foodstuffs, and readily indicated any that contained peanut. This method enables analysts to test, for the first time, for the presence of peanuts in food in a fast and easy‐to‐use manner. The availability of such technology makes the task of monitoring foods for contamination by peanuts readily achievable, providing the industry with an important tool for quality control of raw materials, processes and products. Increased testing will give consumers, particularly those sensitive to this potent allergen, increased assurance as to the safety of the food they eat.

ISSN:0954-0105    

DOI:10.1080/09540109709354932

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

An indirect competitive ELISA was developed for the quantitative analysis of aldrin/dieldrin. This has been used to monitor the levels of these pesticides in water samples collected in Egypt. The detection range of the aldrin/dieldrin assay in water was 5–10 ppm without enhancement. River Nile water samples and tap water samples (n = 25) were collected from 25 stations in 16 different governorates in Egypt. Pesticides were detected in 10 of the 25 Nile water samples (40%) at levels from 10 to 110 ppb. In tap water samples, pesticides were not detected at levels greater than the lower limit of the assay. The technique described provides a rapid, economical, highly sensitive and specific method of analysis that is relatively simple to perform and interpret. It will be extremely useful in monitoring levels of pesticides in water used for human consumption.

ISSN:0954-0105    

DOI:10.1080/09540109709354933

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The growth at — 1.5°C of Lactobacillus delbrueckii, a meat spoilage organism, was evaluated on vacuum‐packaged lamb legs obtained from animals immunized against that organism. Growth was significantly lower than that on similarly treated legs obtained from non‐immunized lambs. These findings suggest that immunization against spoilage organisms may contribute toward increasing the chilled storage life of fresh meat.

ISSN:0954-0105    

DOI:10.1080/09540109709354934

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Crisis Management in the Food and Drinks Industry—A Practical Approach

ISSN:0954-0105    

DOI:10.1080/09540109709354935

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0954-0105    

DOI:10.1080/09540109709354928

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor