Effect of Agitation on Bacterial Aggregates in Pure Cultures and Raw Milk

O'Connor, Robyn E.; Ewings, K. N.; Hollywood, N.

doi:10.4315/0362-028x-46.8.681

Cited by 9 publications

(7 citation statements)

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“…To break up and scatter the clumps of Map , the suspension was drawn up and expelled 15–20 times by a syringe (O'Connor et al . ). Homogeny of the cell dispersion and also the approximate quantity of Map in the suspension was estimated by direct microscopic observation using Thoma slide.…”

Section: Methodsmentioning

confidence: 97%

“…The culture tube was centrifuged at 4000 g for 20 min and resuspended in 2Á5-ml phosphate-buffered saline (PBS) containing 0Á05% (w/v) Tween 20 (PBS-T) (Merck, Darmstadt, Germany) at pH 7Á4. To break up and scatter the clumps of Map, the suspension was drawn up and expelled 15-20 times by a syringe (O'Connor et al 1983). Homogeny of the cell dispersion and also the approximate quantity of Map in the suspension was estimated by direct microscopic observation using Thoma slide.…”

Section: Preparation Of Map Inoculamentioning

confidence: 99%

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Survival ofMycobacterium aviumsubsp.paratuberculosisin ultra-filtered white cheese

Hanifian

2014

Lett Appl Microbiol

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Significance and Impact of the Study: This study was conducted to investigate the factors that influence the survival of Mycobacterium avium subsp. paratuberculosis (Map) during the storage period of ultrafiltered white (UFW) cheese which represents a step forward to meet a critical industry need. Results revealed that the addition of starter culture could restrict the persistence of Map, while Map survival was not affected by higher salt concentration. In addition, persistence of Map was found dose-dependent. It was concluded that in UFW cheese, Map could survive the 60 days of storage period. Abstract Mycobacterium avium subsp. paratuberculosis (Map) is considered as a potential public health threat due to its possible association with Crohn's disease in humans. This study aimed to investigate the survival of Map in ultra-filtered white (UFW) cheese, with special reference to the effect of initial inoculum level, addition of starter culture and salt concentration. Behaviour of Map was monitored during the storage of UFW cheese using F57-quantitative real-time PCR and culture assay. According to the results, higher inoculum level prolongs Map persistence in UFW cheese. Furthermore, the addition of starter culture was found as the main restrictive parameter affecting the survival of Map in UFW cheese. Meanwhile, salt concentration did not accelerate Map inactivation. It was concluded that UFW cheese has potential to support the survival of Map.

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Section: Methodsmentioning

confidence: 97%

Section: Preparation Of Map Inoculamentioning

confidence: 99%

Survival ofMycobacterium aviumsubsp.paratuberculosisin ultra-filtered white cheese

Hanifian

2014

Lett Appl Microbiol

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“…Both strains were grown at 37°C for 4 months in Middlebrook 7H9 broth (BD Biosciences, Erembodegem, Belgium), supplemented with oleic acid‐albumin‐dextrose‐catalase (OADC, 10%; BD Biosciences) and mycobactin J (2 μg ml −1 ; Allied Laboratories Inc., Synbiotics Europe SAS, Lyon, France). Prior to use, liquid cultures were syringed 20 times to disrupt large clumps, as described by O’Connor et al. (1983): the suspensions were drawn up by a syringe and expelled through a 0·8 × 40 mm needle (BD Biosciences).…”

Section: Methodsmentioning

confidence: 99%

Survival of Mycobacterium avium ssp. paratuberculosis in yoghurt and in commercial fermented milk products containing probiotic cultures

Brandt¹,

Coudijzer²,

Herman³

et al. 2011

Journal of Applied Microbiology

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Aims: To assess the survival of Mycobacterium avium ssp. paratuberculosis (MAP) in yoghurt and commercial fermented milk products containing probiotic strains. Methods and Results: Whole and skimmed UHT milk artificially inoculated with MAP were used to manufacture yoghurt, using two different yoghurt starter cultures. Five commercial fermented milk products were inoculated with MAP. Two different MAP strains were studied. The survival of MAP in all products was monitored by culture over a 6‐week storage period at 6°C. In yoghurt, MAP counts did not change appreciably during the storage period. Fat content and type of yoghurt starter culture had no consistent effect on the survival of MAP. In the fermented milk products, survival patterns varied but resulted in a 1·5 to ≥3·8 log reduction for the Niebüll strain and a 1·2–2·2 log reduction for the NIZO strain after 6 weeks, depending on the probiotic starters present in the product. Conclusions: MAP easily survived in yoghurt but MAP numbers decreased in fermented milk products containing probiotic cultures. Significance and Impact of the Study: The results contribute to the lack of knowledge on the behaviour of MAP in yoghurt and fermented milk products containing probiotic cultures. This knowledge is valuable in the context of the risk of MAP transmission to humans via yoghurt and the possible contribution of probiotic fermented milk products to the elimination of MAP.

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“…The arrival of a new committed supplier resulted in the development of more purpose-built equipment such that the DEFT is easier to carry out. This has renewed interest and confidence in the technique such that its wider application is being investigated worldwide (Boisen, 1983;O'Connor et al, 1983;Qvist & Jakobsen, 1985;Suhren and Heeschen, 1985;Pettipher, 1987).…”

Section: Discussionmentioning

confidence: 99%

Observations on the introduction of the DEFT for the routine assessment of bacteriological quality

Easter

Kroll²,

Farr³

et al. 1987

Int J of Dairy Tech

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In the light of experiences gained and observations made in the dairy industry, the critical control points and factors that affect the operation of the DEFT (Direct Epifluorescent Filter Technique) in a routine laboratory were determined. Recommendations are made for the optimization of both the test protocol and the instrumentation, and the need for adequate operator training is strongly emphasized.

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Effect of Agitation on Bacterial Aggregates in Pure Cultures and Raw Milk

Cited by 9 publications

References 0 publications

Survival ofMycobacterium aviumsubsp.paratuberculosisin ultra-filtered white cheese

Survival ofMycobacterium aviumsubsp.paratuberculosisin ultra-filtered white cheese

Survival of Mycobacterium avium ssp. paratuberculosis in yoghurt and in commercial fermented milk products containing probiotic cultures

Observations on the introduction of the DEFT for the routine assessment of bacteriological quality

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