A comparison of contact plate and calcium alginaie swab techniques for quantitative assessment of bacteriological contamination of environmental surfaces

Scott, Elizabeth; Bloomfield, Sally F.; Barlow, C. G.

doi:10.1111/j.1365-2672.1984.tb01353.x

Cited by 26 publications

(12 citation statements)

References 4 publications

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“…To determine the number of E. aerogenes cells on the spigots, one of the three spigots was sampled by the alginate swab method, which was reported to be more sensitive than other sampling methods (3,12,18,27). Briefly, an alginate swab (Fisher Scientific Co.) was moistened in 0.8% saline and swabbed over the entire spigot surface (ϳ25 cm 2 ).…”

Section: Preparation Of Culturesmentioning

confidence: 99%

Inoculum Size Influences Bacterial CrossContamination betweenSurfaces

Montville

Schaffner

2003

Appl Environ Microbiol

121

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Many factors have been shown to influence bacterial transfer between surfaces, including surface type, bacterial species, moisture level, pressure, and friction, but the effect of inoculum size on bacterial transfer has not yet been established. Bacterial cross contamination rates during performance of common food service tasks were previously determined in our laboratory using nalidixic acid-resistant Enterobacter aerogenes. Eight different transfer rates were determined, each involving a minimum of 30 volunteers. The influence of source inoculum level on the percentage of bacteria transferred (percent transfer rates) and log 10 CFU per recipient surface was determined using statistical analysis. The effect of inoculum size on transfer rate was highly statistically significant (P < 0.0001) for all transfer rate data combined (352 observations) and for each individual cross contamination rate, except for data on contamination via transfer from chicken to hand through a glove barrier (P ‫؍‬ 0.1643). Where inoculum size on the source was greater, transfer rates were lower, and where inoculum size on the source was less, transfer rates were higher. The negative linear trend was more obvious for activities that had a larger range of inoculum sizes on the source surface. This phenomenon has serious implications for research seeking to determine bacterial cross contamination rates, since the different transfer efficiencies that were previously shown to be associated with certain activities may actually be the result of differing initial inoculum levels. The initial inoculum size on the source and the amount of bacteria transferred must both be considered to accurately determine bacterial transfer rates.Microbial concentration plays an essential role in many microbial systems. It plays an essential role in regulating bioluminescence (8), antibiotic biosynthesis (1), virulence determination (20), catalase activity (6), and initiation of chromosomal replication (29). Bacillus megaterium spores germinate faster when present at higher concentrations (4). The inoculum size of Clostridium botulinum affects time to detection and the fraction of samples that show growth (30). A threshold inoculum size for Listeria monocytogenes to initiate growth at suboptimal conditions has been established (19,23). Whether due to interaction between cells, statistical effects, or sensitivity of microbiological methods, initial inoculum levels can drastically affect experimental results.Many factors that influence the transfer of bacteria from surface to surface have been identified. Type of bacteria (14, 24), source and destination surfaces (5, 10, 24), time postinoculation (26), and moisture level (10, 25) have all been shown to affect cross contamination rates. However, the effect of the initial inoculum level on transfer efficiency has not been established.Research conducted in our laboratory to determine the effectiveness of gloves as a barrier to cross contamination identified inoculum size as a possible factor influencing the percent t...

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Section: Preparation Of Culturesmentioning

confidence: 99%

Inoculum Size Influences Bacterial CrossContamination betweenSurfaces

Montville

Schaffner

2003

Appl Environ Microbiol

121

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“…Therefore, when the number of CFU/cm 2 calculated from colony numbers on the DA-NSF was less than one colony per square centimeter, it was assumed the same result as indicated by zero colonies per square centimeter by the swab method. We approve the view that the agar contact method is the more suitable for extensive environmental survey work and should be the method of choice where lower levels of contamination are expected (SCOTT et al 1984). Considering both recovery and repeatability, the contact plate method was more suitable for a flat and firm surfaces.…”

Section: Resultsmentioning

confidence: 84%

“…These techniques, however, are not so easy to carry out for estimating bacterial contamination on surfaces. Several comparative studies for the swab and agar contact methods (FAVERO et al 1968, NISKANEN and POHJA 1977, SCOTT et al 1984 and for microbiological sampling of poultry carcasses have been reported (FROMM 1959). However, little work has been done on comparing the agar contact plate method and the swab method for usefulness in estimating bacterial contamination in poultry processing plants.…”

mentioning

confidence: 98%

“…The agar contact method (FAVERO et al 1968, GUNDERSON et al 1947, NISKANEN and POHJA 1977, SCOTT et al 1984, WALTER and HUCHER 1941, WALTER and CARD 1962 is the simplest and easiest to do when the plate is ready for using. On the other hand, the swab method (FAVERO et al 1968, NISKANEN and POHJA 1977, RICHARD 1980, SCOTT et al 1984, WALTER and HUCHER 1941, WALTER and CARD 1962 is commonly used for bacterial sampling of surfaces. However, the rinse technique (FAVERO et al 1968), the direct surface agar plating technique (FAVERO et al 1968), the excised tissue sampling (SCHOTHORST 1976), and the quantitative method (GALTON et al 1955) give better recovery rates than the swab method.…”

mentioning

confidence: 98%

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Comparative evaluation of the Desoxycholate Agar Nissui Food Stamp and swab methods for estimating coliform organisms in poultry processing plants after cleaning in Japan

Kodaka

Goto

Umeki³

et al. 2004

J. Basic Microbiol.

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Bacterial control in poultry processing plants is very important, but the swab method for estimating bacterial contamination is somewhat troublesome in routine work. We compared the Desoxycholate Agar Nissui Food Stamp (DA-NFS) based on the agar contact method with the swab method to estimate coliform organisms from various equipments in four poultry processing plants after cleaning. Overall 104 surfaces for coliform organisms were evaluated. The results from 98 (94.2%) surfaces for coliform organisms were equivalent by the DA-NFS and swab methods and there were no significant differences between two methods (P > 0.05). The correlation coefficient between the DA-NFS and swab methods was 0.91. We conclude that the DA-NFS could be useful for routine coliform organisms examination in poultry processing plants after cleaning in Japan.

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“…Previous studies (Scott et al, 1984;Rusin et al, 1998) have shown that dishcloths are a potential health hazard unless they are thoroughly dried after use, which is not often the case. However, most of these studies investigated microbial contamination on dishcloths and sponges in domestic kitchens.…”

Section: Y-m Bae Et Almentioning

confidence: 98%

Survival and Growth of Foodborne Pathogens on Commercial Dishsponges/cloths and Inhibitory Effects of Sanitizers

Bae¹,

Lee²,

Yoo³

et al. 2012

FSTR

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This study was investigated the survival and growth of pathogens on commercial dish sponges and cloths when contaminated with organic materials and the effects of chemical sanitizers and organic acids on inhibiting pathogens contaminating the dish sponges and cloths. When pathogens were inoculated with TSB, none of the four pathogens grew in the cellulose sponge until 12 h of storage; however levels of pathogens on the other samples were significantly increased after 24 h of storage. When chemical sanitizers and organic acids were added to the dish sponges and cloths, treatments with hydrogen peroxidebased sanitizer, lactic and propionic acids were the most effective at reducing levels of E. coli O157:H7 and S. aureus, whereas treatment with a chlorine sanitizer did not significantly reduce pathogen levels.

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A comparison of contact plate and calcium alginaie swab techniques for quantitative assessment of bacteriological contamination of environmental surfaces

Cited by 26 publications

References 4 publications

Inoculum Size Influences Bacterial CrossContamination betweenSurfaces

Inoculum Size Influences Bacterial CrossContamination betweenSurfaces

Comparative evaluation of the Desoxycholate Agar Nissui Food Stamp and swab methods for estimating coliform organisms in poultry processing plants after cleaning in Japan

Survival and Growth of Foodborne Pathogens on Commercial Dishsponges/cloths and Inhibitory Effects of Sanitizers

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