Further studies of incubation at 44° C. as a test for ‘faecal coli’

Sherwood, H. P.; Clegg, L. F. L.

doi:10.1017/s0022172400012626

Cited by 15 publications

(5 citation statements)

References 9 publications

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“…From this result it appears that use of the MacConkey agar roll tube would provide a specific test for faecal coli. (Sherwood & Clegg, 1942). Table 6 gives the results of testing 1000 red colonies which grew at 440 from eight samples of mussels, one sample of oysters and one sample of cockles.…”

Section: Special Medium In Roll Tubesmentioning

confidence: 99%

The bacteriological examination of molluscan shellfish

Clegg

Sherwood

1947

Epidemiol. Infect.

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Section IA standard bacteriological test for molluscan shellfish should fulfil certain requirements stated: briefly, the test should show the degree of pollution, be accurate and rapid, and self-sufficient, not requiring subsequent confirmation. Review of the subject leads to recommendations, first, to overcome the technical difficulties of preparing samples for testing; secondly, on the nature of the test. In preparation: external shell sterilization can usually be omitted, shell water should be discarded and replaced by sterile water to make a total volume three times that of the body tissues. Pooling of individual shellfish into one sample is acceptable in routine examinations. In the test: a solid medium is preferable to a liquid medium, giving more accurate results, and review of existing tests leads to the conclusion that the use of roll tubes of MacConkey agar incubated at 44° should meet the requirements of a standard test.Section IIA modification was found necessary in the MacConkey agar: a mixture of 2 % gelatin and 5 % agar is used instead of the normal 2 % agar. Mechanical rolling devices for tubes are described and figured.Among other critical experiments, 1000 roll-tube colonies grown at 44° from shellfish included 969 with + + − − ‘IMViC’ reactions and 979 acid and gas producers at 44°. The coefficient of variation among replicate tests of samples of shellfish and water in roll tubes was not seriously greater than that for colony counts in Petri dishes at 37° with ordinary MacConkey agar.Colonies in roll tubes incubated at 44° can be counted as conveniently and accurately as those on Petri dishes, and, in general it is concluded that the new method is more satisfactory for estimation of faecalcolithan other methods at present in use.Section IIIDirections are given for the preparation of shellfish and inoculation into roll cultures, both for individual and for pooled examination, and the method of determining results is described.The interpretation of results is discussed, and it is suggested that shellfish which in four out of five samples from the same source are free from faecalcoliin 1 ml. quantities of body tissue should be regarded as satisfactory for food. The presence of more than two or three faecalcoliper ml. of body tissue in any one sample calls for appropriate action according to the number present.

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Section: Special Medium In Roll Tubesmentioning

confidence: 99%

The bacteriological examination of molluscan shellfish

Clegg

Sherwood

1947

Epidemiol. Infect.

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“…This is because the foodstuff itself is not inert but may affect the physicobiochemical environment in which the organism-medium reaction occurs; the associated bacterial flora may be of a nature to compete more successfully with the indicator organism; and finally the handling and storage of the foodstuffs may debilitate the indicator organism. MacConkey (1901) and Eijkman (1904) used elevated temperatures for the recovery of coliforms, and indeed the British have had a continuing experience with MacConkey's broth in the approximate range of 44 C (Wilson et al, 1935;Bardsley, 1938;Sherwood and Clegg, 1942;Taylor, 1945;Taylor, Jones, andFranklin, 1951: Thomas et al, 1955).…”

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Comparison of the Recovery of Escherichia coli from Frozen Foods and Nutmeats by Confirmatory Incubation in EC Medium at 44.5 and 45.5 C

Fishbein¹,

Surkiewicz²

1964

Applied Microbiology

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FISHBEIN, MORRIS (Food and Drug Administration, Washington, D.C.), AND BERNARD F. SURKIEWICZ. Comparison of the recovery of Escherichia coli from frozen foods and nutmeats by confirmatory incubation in EC medium at 44.5 and 45.5 C. Appl. Microbiol. 12:127-131. 1964.-The productivity of confirmatory EC broth for the isolation of fecal Escherichia coli was determined at 44.5 and 45.5 C. A variety of frozen precooked foods and an assortment of nutmeats were examined after primary incubation in Lauryl Sulfate Tryptose (LST) broth. In 85.3% of the cases, the parallel tubes of EC broth incubated for 24 hr at 44.5 and 45.5 C gave rise to identical E. coli responses of positive, false positive, and negative. The remaining 14.7% of the reactions represent the qualitative difference between the two temperatures. The EC test at 45.5 C was more specific for E. coli, since twoto threefold fewer false positives were produced at this temperature than at 44.5 C. However, fecal E. coli recoveries were slightly higher (4%Vc) at the lower temperature. Incubating the EC tubes from the interval of 24 to 48 hr gave rise to an additional 4.3% of E. coli recovery, but this was accompanied by an excessive production of false positives (75.9%), representing a 3.5-fold decrease in specificity. It is recommended that, in the confirmatory use of EC broth in the examination of frozen foods and nutmeats for the recovery of fecal E. coli, the test be made at 45.5 C in a water bath and limited to 24 hr of incubation only, to insure optimal specificity. During the study, a "fixed" productivity ratio was noted; E. coli+/LST+ equaled approximately one-fourth or 25%. The significance of this ratio is discussed.

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“…Adesina [11] identified E. fergusonnii from non-clinical samples from patients in a general hospital in Lagos, Nigeria. Similarly, to other Escherichia spp., E. fergusonii grows optimally on routine culture media at 37-40 • C under aerobic conditions but its temperature range of growth extends up to 45 • C [12,13] and according to Ingle et al [14] E. fergusonii cannot replicate at temperatures below 11 • C.…”

Section: Introductionmentioning

confidence: 98%

A Study of the Antimicrobial Activity of Combined Black Pepper and Cinnamon Essential Oils against Escherichia fergusonii in Traditional African Yoghurt

Ogwaro

O’Gara

Hill

et al. 2021

Foods

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The antimicrobial activity of the essential oils of black pepper (BPE) and cinnamon bark (CE) extracts against E. fergusonii was assessed in pasteurized full cream milk during and post-fermentation. The milk was fermented with 1% (v/v) of Lactobacillus delbrueckii subspecies bulgaricus (NCIMB 11778) and Streptococcus thermophilus (NCIMB 10387) (approx. 106 cfu/mL each) and incubated and stored at 25 °C for 5 days (144 h) or at 43 °C for 24 h and then stored at 25 °C for 120 h. The milk was spiked with E. fergusonii at the start of fermentation by the lactic acid bacteria (pre-fermentation contamination) for after fermentation (post fermentation contamination). BPE and CE were applied at concentrations based on their minimum inhibitory concentration of 0.5% and 0.25% respectively as follows: 0.5% BPE alone; 0.125% BPE with 0.1875% CE; 0.25% BPE with 0.125% CE; 0.375% BPE with 0.0625% CE; 0.25% CE alone. Results showed that during fermentation at 25 °C, E. fergusonii grew to a similar level (approx. 109 CFU/mL) in control samples and 108 CFU/mL when BPE or CE were added alone. Whereas, in the samples with the combined essential oils, the bacterium grew to 106–107 CFU/mL only. During the milk fermentation at 43 °C, E. fergusonii grew to approx. 109 CFU/mL in samples without treatment. However, it was not detected in samples containing mixed BPE with CE after 8, 10 and 12 h of fermentation. Subsequent storage at 25 °C resulted in undetectable levels of the bacterium in all the samples treated with BPE or CE after 24 h of storage. These results indicated that BPE in combination with CE reduced growth during fermentation and was bactericidal during storage.

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Further studies of incubation at 44° C. as a test for ‘faecal coli’

Cited by 15 publications

References 9 publications

The bacteriological examination of molluscan shellfish

The bacteriological examination of molluscan shellfish

Comparison of the Recovery of Escherichia coli from Frozen Foods and Nutmeats by Confirmatory Incubation in EC Medium at 44.5 and 45.5 C

A Study of the Antimicrobial Activity of Combined Black Pepper and Cinnamon Essential Oils against Escherichia fergusonii in Traditional African Yoghurt

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