Comparison of Direct Plating Media for the Isolation and Enumeration of Enterococci in Certain Frozen Foods1

Burkwall, Mary K.; Hartman, Paul A.

doi:10.1128/aem.12.1.18-23.1964

Cited by 20 publications

(6 citation statements)

References 12 publications

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“…Evaluation of the efficiency of several media previously proposed for enterococci have shown several problems; the medium suggested by Barnes (1965) required much experience and expertise for distinction between S. fuecium and S. fueculis, and that described by Mead (1963) yielded very low recoveries with freeze injured cultures. KF medium was found most efficient for the recovery of enterococci from frozen foods (Burkwall and Hartman 1964). We found that The relative density of chains comprised of a t least 3 cells in the total cell population of the cultures was determined microscopically ( Fig.…”

Section: Selective Medium For S Faecalissupporting

confidence: 80%

STREPTOCOCCUS FAECALIS AND STREPTOCOCCUS FAECIUM IN FROZEN VEGETABLES. INCIDENCE AND SURVIVAL AFTER TREATMENTS COMMONLY USED AT THE VEGETABLE FREEZING PLANTS

Sadovski

Farber

1980

Journal of Food Safety

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S. faecium predominated in fresh vegetables which were not irrigated with sewage treatment plant water. Vegetables which were irrigated with waste water from a sewage treatment plant contained equal numbers of the two species. S. faecium survived the effect of chlorination better than S. faecalis. The tendency for chain aggregate formation was more prominent in S. faecalis especially during exponential growth. This affected the recoveries after freezing but not after the chlorination treatment. With exponential cultures which were treated for aggregate dispersal and with stationary cultures, S. faecium survived the effect of freezing better. This indicates a higher resistance of this organism and that the vegetable treatments in the freezing plant may result in a relative enrichment in S. faecium. Thus, enterococcal count in frozen vegetables is comprised to a large extent of this group, a fact which reduces the significance of the enterococci as a sanitary indicator. A specific S. faecalis count may be a better indicator of the sanitary quality of frozen vegetables and may be performed with KF agar supplemented with 0.04% K2 Te03.

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Section: Selective Medium For S Faecalissupporting

confidence: 80%

STREPTOCOCCUS FAECALIS AND STREPTOCOCCUS FAECIUM IN FROZEN VEGETABLES. INCIDENCE AND SURVIVAL AFTER TREATMENTS COMMONLY USED AT THE VEGETABLE FREEZING PLANTS

Sadovski

Farber

1980

Journal of Food Safety

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“…The MBA medium of Schaedler et al (11) is a highly selective medium for the isolation of group D enterococci. It may be considered as a high selectivity-low yield type of medium (1). Such a medium is generally of limited value.…”

Section: Discussionmentioning

confidence: 99%

Use of a Methylene Blue Azide Medium for Isolation of Enterococci

Smith¹,

Bodily²

1967

Applied Microbiology

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A methylene blue azide medium (MBA), developed by Schaedler. Dubos, and Costello to isolate enterococci from the gastrointestinal tract of animals, was evaluated. This was done by comparing the isolation of enterococci from feces and saliva on the medium. Fifty-two catalase-negative, gram-positive cocci from human feces isolated from MBA were classified as enterococci. All strains grew in S F, 6.5% NaCl, and streptomycin broths, and all fermented mannitol. The isolates were provisionally subdivided into Streptococcus faecalis and S. faecium groups. S. faecalis-like strains fermented glycerol and pyruvate aerobically and produced acid in Synder's medium (initial pH, 4.8). The S. faecium group fermented raffinose. Among all strains, several tests were variable. These included growth at 45 C, in 0.1 % tellurite and in methylene blue milk. Three methods were employed to isolate and identify enterococci from the oral cavity. Direct streaking of MBA with saliva failed to produce any growth on the medium. Two other methods, with the use of various selective broths to promote the recovery of oral enterococci, failed to produce any bacteria capable of growing on MBA. The MBA-isolated fecal strains and oral viridans streptococci were generally indistinguishable on Mitis-Salivarius and K F agars. In experiments with fecal material, no gram-negative bacilli were found among the isolates selected. The MBA medium was judged as a high selectivity-low yield medium, and may provide a means of separating fecal and nonfecal enterococci. Efforts to develop media for the successful isolation, enumeration, and identification of

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“…(1960) placed such strains in an 'enterococcus biotype ' group andMieth (1960,1961) placed such strains in an 'atypical enterococcus' group. Burkwall and Hartman(1964) also had t o designate an 'atypical enterococcus' group to accommodate many of the strains isolated in their study. (See also F e r r a r o , 1960.)…”

Section: Definition Of T E R M Smentioning

confidence: 99%