摘要:

An electronic counting system using hydrophobic grid‐membrane filters (HGMF) and the HGMF Interpreter was evaluated for its usefulness in enumerating nalidixic acid resistantSalmonellain frozen chicken caeca.Salmonellarecovery was equivalent on both Hektoen Enteric and EF‐18 agars. However, the color of theSalmonellagrowth on EF‐18 agar was more easily differentiated by the HGMF Interpreter electronic counting system. the study showed that a 4 h resuscitation on a nonselective medium was required in order to maximize the subsequent recovery on Hektoen Enteric agar, though not on EF‐18 agar. Using the EF‐18 agar as theSalmonellaselective medium, a method was established that recorded counts of nalidixic acid resistantSalmonellarapidly and easily in electronic data files, for subsequent retrieval and man

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1992.tb00083.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The speed of ATP bioluminescence assays makes them very useful for assessing product quality and efficiency of sanitation at food plants. the suitability of a new method for evaluating the quality of raw milk was compared with plate count. A good correlation was obtained between the ATP method and plate count for milks with counts above 1 × 104cfu/ml. the combination of ATP bioluminescence with preincubation procedures was investigated for predicting the shelf‐life of pasteurized milk. the best correlations were obtained when milks were preincubated at 15C for 25 h or at 21C for 25 h in the presence of an inhibitor system to prevent Gram‐positive bacterial growth.Hygiene monitoring using bioluminescence gave a better indication of surface cleaniness than conventional swab counts. the reasons for the discrepancies in a small percentage of cases are discu

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1992.tb00084.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Two monoclonal antibodies (AMb) that react only withMycoplasma gallisepticum(MG) and do not cross‐react withMycoplasma synoviae(MS) were established. MAb 76 was IgG1 and reacted with a 66 kDa MG protein. MAb 69 was IgG2b and reacted with a 100 kDa MG protein. Using these MAbs as positive controls in an immunoblotting test, 9 of 12 sera from MG inoculated chickens gave a strong band at 66 kDa, and no bands were found at 66 kDa using either 11 sera from MS inoculated chickens or 10 sera from uninoculated, negative control chickens. These results indicated that the 66 kDa protein is a major species‐specific protein for MG and that the MAb 76 is a major species‐specific monoclonal antibody for MG. the MAb 76 identified 7 of 7M. gallisepticumstrains by a cell‐dot‐blot method. A coagglutination test using MAb 76 bound to protein A positiveStaphylococcus aureuscells was also shown to be a rapid method to identify the seven strains ofM. gall

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1992.tb00085.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

In conventional latex‐particle agglutination tests, latex beads are either coated with antibody and clump if antigen is present in a sample or are coated with antigen and clump if an antibody is present in a sample. Ligands other than antigen and antibody have not been used previously for latex‐particle agglutination tests. We report here a new variation, a sandwich latex‐particle agglutination test in which interactions between GM1 gangliosides, antigen (cholera toxin) and anticholera antibody are used to affect agglutination. the principles that are described can be applied to develop tests for the rapid detection of other small li

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1992.tb00086.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Using an agar overlay technique, we determined that colonies of both Gram‐positive and Gram‐negative bacteria could reduce tellurite. We also observed that under anaerobic conditions, the growth of Gram‐positive bacteria was inhibited if tellurite was present in the plating m

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1992.tb00087.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

A miniaturization of the enrichment serology method for the detection ofSalmonellawas improved in order to make the technique more reliable, cheaper, and faster. the miniaturized method (“Micromethod”) was compared to the Sperber and Deibel's method (“Macromethod”) and with a classical isolation method; 1062 samples including 700 rearing farms environment samples, 247 poultry meat samples, and 115 nonfat dry milk samples were analyzed. Specificity of both enrichment serology methods was about 92–99.4%. Sensitivity of Micromethod was better than that of the Macromethod for the environmental samples (86.8 and 74.1%, respectively) and the poultry meat samples (87.5 and 77.5%, respectively) but was the same for the nonfat dry milk samples (82.5%). the costs of both methods were respectively 0.43 US $ for the Macromethod and 0.20 US $ for the Micromethod. This “Micromethod” could be proposed for the screening ofSalmonellapositive batches in the fo

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1992.tb00088.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The analytical sensitivities of three different enzyme linked immunoassays (ELISA), two competitive and a capture format were assessed. the assay systems employed monoclonal antibodies toSalmonellalipopolysaccharide (LPS) outer core epitopes to detect crude LPS antigens fromSalmonella typhimurium.the most sensitive ELISA was the capture procedure, being capable of detection 1.3 ng/ml of LPS. This technique, however also gave the greatest between‐test variation and as a result, the lowest amount that could be detected with a 95% confidence limit was actually 12.8 ng/ml and it took the longest time to perform (3 h, 30 min). A competitive ELISA using limiting monoclonal antibody to compete between solid phase antigen and soluble antigen in the sample, ranked second in sensitivity, and can detect 2.8 and 3.8 ng/ml of LPS when tested with two different monoclonal antibodies. However, because of the slight between test variation, the actual sensitivities that could be detected with a 95% confidence limit were 3.1 and 4.6 ng/ml, respectively. This test takes approximately 1 h and 30 min to perform.The classical type of competitive assay, employing a labelled antigen, was the least sensitive being capable of detecting 5.8 ng/ml if the LPS was conjugated with horseradish peroxidase and 16.0 ng/ml if alkaline phosphatase was used as a label. to account for the between‐test variation, the sensitivities with a 95% confidence limit were 8.6 and 18.7 ng/ml for the respective assays, which take 2 h and 15 min to perform.These sensitivities compare favorably with those published for similar assays, but all of the procedures were judged insufficiently sensitive for direct use on food samples to be tested for the presence ofSalmonellaspecies. However, the assays would be quite suitable for demonstration ofSalmonellasp. after an enrichment proced

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1992.tb00089.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The importance ofSalmonellaandListeria monocytogenesin food safety is well‐known. Recovery of these organisms is usually done in different types of enrichment broths. Recently Bailey and Cox (1992) reported the development of a “Universal Preenrichment Medium” capable of recovering bothSalmonellaandListeria monocytogenes, thus eliminating the need of using two broths to enrich these important foodborne pathogens. In our laboratory we have ascertained that Oxyrase, an oxygen scavenger, is able to allow the rapid growth ofListeria monocytogenesand otherListeriaspp. (Yu and Fung 1991a) as well as other facultative anaerobic foodborne pathogens (Yu and Fung 1991b). It seems reasonable that Oxyrase will be able to stimulate growth ofSalmonellaspp. andListeria monocytogenesin the “Universal Preenrichment Medium.” the purpose of this investigation was to ascertain the stimulatory capability of Oxyrase onSalmonellaspp. andListeria monocytogenesin the “Universal Preenrichm

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1992.tb00090.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1992.tb00082.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY