ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00082.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Spores ofBacillus subtiliswere subjected to a 24 h exposure (22 d̀C) to vaious commercial and non‐commercial aldehyde formulations Subsequent treatment with sodium hydroxide (15 min, 22 d̀C)enabled the recovery of injured spores as determined by enumeration on nutrient agar. Greatest revival was obtained with spores treated with glyoxal, followed by 2% alkaline glutaraldehyde, Sporicidin and 10% Gigasept. Revival was dependentupon neutralization of residual aldehyde with 2% (w/v) glycine prior to alkali treatment. Two percent alkaline glutaradehyde‐treated spores were also exposed to to proteases, proteinase K and pronase. No revival was observed. The results are discussed in terms of the mechanism of action of the aldehydes used, with particular emphasis on glutarad

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00083.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

During growth in a glucose‐tryptone‐mineral salts broth,B. thuringiensisHD‐1 Produced lactate, pyruvated, acetate, acetoin, and poly‐beta‐hydroxybutyrate (PHB). Based on the type and sequence of products found, all or part of the acetate appears to have been produced via the 2,3‐butanediol cycle. PHB was produced and utilized during spore formation and may have provided energy for t

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00084.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The behaviour of Salmonella enteritidis phage type 4 in home‐made mayonnaise was studied. Samples of mayonnaise were prepared with different pH values using wine vinegar or lemon juice in order to bring down the pH to 5,4.5,4 and 3.6, inoculate and incubated at 4, 24 and 35d̀C for 5 days. The results showed a better bactericidal activity of the vinegar (acetic acid) than the lemon juice (citric acid), both of these acids being more active at higher temperatures. For preventing salmonellosis transmission by home‐made mayonnaise the use of vinegar as an acidulant in order to achieve a pH between 3.6 and 4 and storage in a warm place is recomme

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00085.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A new method of separating bacteria from beef mince has been developed, in which an alkaline protease, Alcalase 0.6 L, was used to degrade the meat proteins, leaving micro‐organisms in suspension. The organisms were then counted, using a membrane filtration‐epifluorescent microscopy technique. A correlation coefficient of 0.9? was obtained between this method and the standard plate count, indicating its suitability for use in quality cont

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00086.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A rapid method for determining the sensitivity ofStaphylococcusaureus to β‐lactarns is described. The method involves the culture of microcolonies of the bacterium on the surface of antibiotic‐containing agar medium on microscope slides. The areas of the microcolonies formed are measured by means of a microscope and image analyzer. The sensitivity of the bacterium can be estimated in 4 h by this technique and the results are comparable to those obtained by overnight incuba

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00087.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The polymerase chain reaction (PCR) was used to identify strains of Escherichia coli which produce heat‐labile toxin type I (LTI). Amplification primers were designed to detect E. coli strains of human as well as porcine origin. This assay was used to test the ATCC 37218 strain, which carries a recombinant plasmid with the genetic information for production of porcine LTI (pLTI). In addition, three clinical E. coli isolates of human and one of porcine origin were tested. All clinical isolates were reported to produce heat‐labile enterotoxin (hLTI and pLTT, respectively) when tested by the Y1 adrenal cell method and/or by the CHO cell method. All strains yielded the expected 275 bp DNA fragment after enzymatic amplification. This fragment was further identified by allele specific oligonucleotide hybridization. Alternatively, the fragment was identified by a Smal restriction enzyme site which is present in the genes of both the E. coli isolated from humans and pigs. The detection limit determined in water with the ATCC 37218 strain was 20 bacteria. The amplified sequence included aCfoIpolymorphism which allowed to distinguish between the genes coding for pLTI and hLTI. All of the strains tested showed this polymorphism as expected. Depending on the identification method chosen,Smaldigestion or oligonucleotide hybridization, pure water can be analysed within 8 h or 12 h, respectively. This method may be adapted to environmental and food samp

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00088.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Samples of dry ‘tatase’ pepper (Capsicum annum L.) stored for sale were purchased from selected markets in Ibadan, Oyo State, between June and October 1988 and subjected to microbial analysis. Mould colony counts ranged from 0.67 times 10′ to 1.6 times 105 within the period of the survey whilst the moisture contents varied between 2.2% and 25.02%. A total of seven mould species were isolated, with Aspergillus niger, Aspergillus fravus and Geotrichum candidum being the dominant

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00089.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Three gastric isolates of Neisseriasubflavanitrosated 2,3‐diaminonaphthalene to a fluorescent triazole product. The bacterial nitrosation rate was optimal at pH 7.5 with glucose as the electron donor for the reduction of nitrite to a nitrosating species. There was a delay period of 6 rnin with nitrite concentrations lower than 20 mmol/l before nitrosation was detecte

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00090.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Fast, intermediate and slow germinatingBacillusspp., isolated from raw milk supplies, were subjected to activation treatments of 80d̀C/10 min, 9d̀C/10 min, 100d̀C/1 min and 100d̀C/10 min. Significant differences were observed between the three spore types at all activation treatments with 80d̀C/10 min giving the highest overall germination rate. The 80d̀C/10 min activation treatment, which is the most commonly used, also favoured germination of the fast germinating spores to a greater extent than the other spore types. The detection of such spores is important because they have the greatest spoilage pote

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1990.tb00091.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY