The waxing step plays an important role in production of ripening cheese, the aim of this research is to introduce different concentration of propolis with bee wax to waxing of Gouda cheese, according to a good charac...The waxing step plays an important role in production of ripening cheese, the aim of this research is to introduce different concentration of propolis with bee wax to waxing of Gouda cheese, according to a good characteristic of propolis as antimicrobial. A prospective study carried on samples of Gouda cheese waxed by local bee wax with different percentage of local propolis, then cheese was ripened for three months at l0℃. It was found that addition （10%, 20% and 30%） of propolis effects of total bacterial count, coliform count, molds and yeasts count, 30% of propolis had a higher incidence during the period of Gouda cheese which was ripened for three months, then the 20%, but the 10% of propolis had a few microbial effects, compared with control treatments that had a high count of bacterial, coliform, molds and yeasts. This study shows that difference was observed between the total bacterial count of control treatment （0% propolis） with other treatments （10%, 20% and 30% of propolis） after three months of Gouda cheese ripened as well as difference was observed between the total bacterial count of treatment （30% propolis） and other treatments. However, there was no difference between the treatments 10% and 20%, the study shows that the coliform count decrease by increase of propolis percent compared with the control treatment which had increase of coliform count during ripened period, and it had a high significant difference in the count of coilform to different treatments, but a considerable difference was not observed between coliform count in the second treatment （20% propolis） and that the third treatment （30%） propolis after three months of ripening, the third treatment had a high difference in growth inhibition of molds and yeasts counts compared with the other treatments after three months of ripened Gouda cheese. It could be observed in general that effects of propolis especially the third treatment was a great on the mold and yeasts which is usually growth on the surface of the cheese.展开更多
A protein conjugate of streptomycin （streptomycin-bovine serum albumin （BSA） conjugate） was prepared and used as immunogen to produce monoclonal antibodies （MAb）. One hybridoma secreting anti-streptomycin MAb wa...A protein conjugate of streptomycin （streptomycin-bovine serum albumin （BSA） conjugate） was prepared and used as immunogen to produce monoclonal antibodies （MAb）. One hybridoma secreting anti-streptomycin MAb was obtained and then used to produce MAb. The MAb named 13H5 showed the 50% maximal inhibitory concentra- tion （IC50） value of 4.65 ng/ml and the IC20value of 0.21 ng/ml in phosphate buffered saline （PBS）. At optimum con- ditions, an indirect competitive enzyme-linked immunosorbent assay （ELISA） and a colloidal gold-based immuno- chromatographic assay （CGIA） were developed and applied to detect streptomycin residues in milk and swine urine samples. The developed ELISA showed that the minimum detection limit was 2.0 and 1.9 ng/ml for milk and swine urine samples, respectively, without obvious cross-reactivity to other tested antibiotics except dihydrostreptomycin which gave a 118.32% cross reaction value. Milk and swine urine samples spiked with streptomycin at 10, 50, 100 and 200 ng/rnl were analyzed by the established ELISA. The mean recovery of streptomycin was from 81.9% to 105.5% and from 84.3% to 92.2% for milk and swine urine, respectively. The optimized CGIA showed that the minimum de- tection limit was 20.0 ng/ml for milk and swine urine samples. The results of spiked analysis and specific analysis demonstrate that the CGIA could be applicable for screening milk and swine urine samples for the presence of streptomycin residues on-site. The established ELISA and CGIA allow the rapid, low-cost, and sensitive determination of streptomycin residues in food samples.展开更多
文摘The waxing step plays an important role in production of ripening cheese, the aim of this research is to introduce different concentration of propolis with bee wax to waxing of Gouda cheese, according to a good characteristic of propolis as antimicrobial. A prospective study carried on samples of Gouda cheese waxed by local bee wax with different percentage of local propolis, then cheese was ripened for three months at l0℃. It was found that addition （10%, 20% and 30%） of propolis effects of total bacterial count, coliform count, molds and yeasts count, 30% of propolis had a higher incidence during the period of Gouda cheese which was ripened for three months, then the 20%, but the 10% of propolis had a few microbial effects, compared with control treatments that had a high count of bacterial, coliform, molds and yeasts. This study shows that difference was observed between the total bacterial count of control treatment （0% propolis） with other treatments （10%, 20% and 30% of propolis） after three months of Gouda cheese ripened as well as difference was observed between the total bacterial count of treatment （30% propolis） and other treatments. However, there was no difference between the treatments 10% and 20%, the study shows that the coliform count decrease by increase of propolis percent compared with the control treatment which had increase of coliform count during ripened period, and it had a high significant difference in the count of coilform to different treatments, but a considerable difference was not observed between coliform count in the second treatment （20% propolis） and that the third treatment （30%） propolis after three months of ripening, the third treatment had a high difference in growth inhibition of molds and yeasts counts compared with the other treatments after three months of ripened Gouda cheese. It could be observed in general that effects of propolis especially the third treatment was a great on the mold and yeasts which is usually growth on the surface of the cheese.
基金Project (No.2007C22047) supported by the Program of Science and Technology of Zhejiang Province,China
文摘A protein conjugate of streptomycin （streptomycin-bovine serum albumin （BSA） conjugate） was prepared and used as immunogen to produce monoclonal antibodies （MAb）. One hybridoma secreting anti-streptomycin MAb was obtained and then used to produce MAb. The MAb named 13H5 showed the 50% maximal inhibitory concentra- tion （IC50） value of 4.65 ng/ml and the IC20value of 0.21 ng/ml in phosphate buffered saline （PBS）. At optimum con- ditions, an indirect competitive enzyme-linked immunosorbent assay （ELISA） and a colloidal gold-based immuno- chromatographic assay （CGIA） were developed and applied to detect streptomycin residues in milk and swine urine samples. The developed ELISA showed that the minimum detection limit was 2.0 and 1.9 ng/ml for milk and swine urine samples, respectively, without obvious cross-reactivity to other tested antibiotics except dihydrostreptomycin which gave a 118.32% cross reaction value. Milk and swine urine samples spiked with streptomycin at 10, 50, 100 and 200 ng/rnl were analyzed by the established ELISA. The mean recovery of streptomycin was from 81.9% to 105.5% and from 84.3% to 92.2% for milk and swine urine, respectively. The optimized CGIA showed that the minimum de- tection limit was 20.0 ng/ml for milk and swine urine samples. The results of spiked analysis and specific analysis demonstrate that the CGIA could be applicable for screening milk and swine urine samples for the presence of streptomycin residues on-site. The established ELISA and CGIA allow the rapid, low-cost, and sensitive determination of streptomycin residues in food samples.
