摘要:

Organic dyes were incorporated in potato dextrose agar individually at various concentrations (1:1000, 1:1,000, and 1:10,000) to test their effects on growth of 43 food‐related molds (e.g., Aspergillus spp. Botrytis spp., Fusarium spp., Penicillium spp., and Rhizopus spp.). Of 43 dyes tested, basic dyes were more inhibitory than acid or nonionic dyes at a given concentration. Basic violet 3 and Basic violet 4 showed potential application for selective isolation of specific food‐mold genera (Aspergillus spp. and/or Penicillium spp). Some dyes (e.g., Acid red 266 and Basic violet 14) contributed their characteristic color to nonpigmented colonies, which helps colony count

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1995.tb00102.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Universal Preenrichment (UP) medium was used successfully for the simultaneous recovery of two strains each of Escherichia coli O157:H7 and Yersinia enterocolitica in the presence of Listeria monocytogenes and Salmonella typhimurium. E. coli O157:H7 and Y. enterocolitica populations reached ca. 108CFU/ml in UP medium in 18 h from an initial level ofca. 102CFU/ml. Addition of OxyraseTMenhanced the growth of both E. coli O157:H7 strains and one strain of Y. enterocolitica. These three strains were able to recover from heat injury by 6 h when 24‐h cultures were tested, but not when 18‐h cultures were used. Injured and noninjured E. coli O157:H7 could be recovered from artificially inoculated food samples (shredded cheddar cheese, turkey ham, hot dogs, mayonnaise, and ground beef) in UP medium supplemented with OxyraseTM(UPO) by 18 h using immunoblotting. Y. enterocolitica could be recovered from turkey ham, hog dogs, and mayonnaise by direct plating on CIN agar from UPO medium. However, recovery of Y. enterocolitica from shredded cheddar cheese and ground beef required subsequent selective enrichment in sorbitol bile broth and isolation on Cefsulodin Irgasan Novobiocin agar (CIN). UPO medium can be used for simultaneous detection of E. coli O157:H7 and Y. enterocolitica from foods. However, subsequent selective enrichment and isolation on selective plating media are required for isolation of Y. enterocolitca from raw foods containing high population levels of background microfl

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1995.tb00103.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A method has been developed to detect thermophilic species of Campylobacter in shellfish, marine and tributary waters, sediment and farm runoff by‐products such as manure and silage. The method consists of a 48 h enrichment incubation and subcultured to selective agars. Presumptive colonies confirmed with a latex agglutination (antibodies) to common flagellar antigens of C. jejuni, C. coli and C. lardi. Over an 8 year period, West Coast estuaries (Washington, Oregon, and California) were sampled, resulting in analysis of a total of 512 samples. Results suggest that Campylobacter spp. are well distributed in the marine environment. Two enrichment broths were compared for the recovery of campylobacters from environmental samples. The method described in the Food and Drug Administration Bacteriological Analytical Manual (FDA/BAM) (1984), was compared to a modified method. Use of the modified method described here resulted in higher recovery rates of Campylobacter spp. Recoveries of campylobacters from sediment, shellfish, and water were 10,13, and 28% higher for the modified method, respectivel

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1995.tb00104.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Bioluminescence has gained acceptance as a rapid technique for quickly assessing the cleanliness of food contact surfaces, and a variety of commercial systems are available. However, with advances in reagents and instrumentation and knowledge of the genetics of the light reaction, the potential of bioluminescence as a tool in food microbiology is only now beginning to be realized. This short review outlines the areas where this technology may have application in the future.

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1995.tb00105.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The present study was designed to evaluate cycloheximide as a potential media amendment to prevent fungal overgrowth on selective media for salmonellae enumeration. The objectives were to determine the effect of cycloheximide on Salmonella spp growth rates and to determine the effect of cycloheximide addition on Salmonella enumeration in selective media. The bacteria tested included two strains of Salmonella typhimurium (NO/NA and LT2) and one strain of Salmonella arizonae. All strains were grown in tryptic soy broth containing cycloheximide to determine the effect of cycloheximide on bacterial specific growth rates. The growth rate of all strains grown in tryptic soy broth were not significantly influenced by addition of cycloheximide at concentrations up to 1,000 mg/L. Growth rates of S. typhimurium NO/NA in minimal media were significantly decreased by addition of cycloheximide aerobically (300 mg/L) and anaerobically (600 mg/L). However, S. typhimurium NO/NA populations on brilliant green agar, MacConkey agar, and from selenite cysteine broth and tetrathionate broth were not affected by cycloheximide additions at concentrations up to 1,000 mg/L. Cycloheximide has potential as a fungistat additive for salmonellae selective media.

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1995.tb00106.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:1060-3999    

DOI:10.1111/j.1745-4581.1995.tb00101.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY