A critical assessment of four most probable number procedures for routine enumeration of cheese-damaging clostridia in milk

Brändle, J; Fraberger, Vera; Schuller, Kristyn; Zitz, Ulrike; Kneifel, Wolfgang; Domig, Konrad J.

doi:10.1016/j.idairyj.2017.05.011

Cited by 9 publications

(3 citation statements)

References 15 publications

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“…DNA for PCR reactions was extracted using a DNA-extraction kit (peqGOLD Bacterial DNA-Kit, VWR, International GmbH, Germany). Afterwards, 16S rDNA PCR was performed on a Mastercylcer nexus (Eppendorf, Austria) according to Brändle et al [ 14 ].…”

Section: Methodsmentioning

confidence: 99%

Effects of selected lactobacilli on the functional properties and stability of gluten-free sourdough bread

Bender

Fraberger

Szepasvári

et al. 2017

Eur Food Res Technol

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The aim of this investigation was to determine the influence of seven different Lactobacillus spp. (Lb.) strains compared with a commercial starter culture (CS) on the functional properties of gluten-free (GF) sourdough-breads. The sourdough stability of selected strains was also evaluated upon back-slopping. Results showed that the bread properties were greatly affected by the Lb. strains. Millet breads achieved lower specific volumes (1.80-2.19 cm 3 /g), higher crumb firmness (19.01-42.19 N) and lower relative elasticities (21.5-43.4%) than buckwheat breads. Compared with the CS, Lactobacillus pentosus and Lb. hammesii positively influenced the crumb firmness of buckwheat and millet breads, respectively, while Lb. paralimentarius enhanced this property in both breads. Only one of the two Lactobacillus sanfranciscencis strains was able to improve all functional properties in both GF breads. Back-slopping of the sourdoughs revealed stable properties in case of buckwheat, while maturity of the millet sourdough could not be reached. These observations were supported by the microbial count, metabolite production and carbohydrate consumption. Mature sourdough significantly improved the crumb firmness and porosity of the GF breads. These results highlighted the importance of selecting the appropriate lactic acid bacteria strains, to maximize the quality of GF bread.

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Section: Methodsmentioning

confidence: 99%

Effects of selected lactobacilli on the functional properties and stability of gluten-free sourdough bread

Bender

Fraberger

Szepasvári

et al. 2017

Eur Food Res Technol

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“…However, it is noteworthy that reported threshold values of spore concentrations that cause quality defects in cheese are highly variable (from 5 to 1,000 spores/L of cheese milk; Dasgupta and Hull, 1989;Stadhouders, 1990;Klijn et al, 1995;Ingham et al, 1998;Jakob, 2005;Ledenbach and Marshall, 2009;Heyndrickx, 2011;Sheehan, 2011). The variation of threshold values partly can be attributed to the plethora of analytical methods used to enumerate clostridia in milk, a fact that has previously been discussed (Brändle et al, 2016(Brändle et al, , 2017.…”

mentioning

confidence: 98%

“…The advantage of the new approach is the specific enumeration of butyric acid-producing clostridia in a selective growth medium containing an indicator dye. Conversely, conventional MPN protocols rely on a less specific growth medium and the detection of gas production, a property that is not exclusively attributed to clostridia (Brändle et al, 2016(Brändle et al, , 2017(Brändle et al, , 2018b. Moreover, the new approach is easy to use, does not require paraffin or agar, and produces less waste than conventional methods that involve glassware.…”

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confidence: 99%

Short communication: Clostridial spore counts in vat milk of Alpine dairies

Burtscher

Hobl

Kneifel

et al. 2020

Journal of Dairy Science

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One of the most severe quality defects in hard and semi-hard cheese, the late blowing defect, is caused by endospore-forming bacteria of the genus Clostridium. To minimize financial losses and waste of resources due to cheese spoilage, raw milk with elevated clostridial spore counts should not be used for the production of certain cheese types. In this context, threshold values of clostridial spore concentrations that cause quality defects in cheese are still under debate. To improve our understanding about late blowing defects, further information on the correlation between clostridial spore concentrations in milk and cheese quality is indispensable. Thus, the aim of this study was to monitor the microbiological quality of milk used for Alpine cheese production regarding clostridial endospore levels to facilitate the establishment of threshold spore concentrations that guarantee the absence of quality defects in Austrian cheese. For this purpose, we monitored clostridial endospore levels in vat milk of 4 Alpine dairies throughout the summer grazing period in 2018. Surprisingly, we observed almost complete absence of butyric acid-producing clostridia in milk and no blowing defects in cheese. Hence, critical clostridial spore concentrations could not be verified. Moreover, the observed low spore levels reveal that the prohibition of silage feeding and good farming practices effectively minimize clostridial endospore counts in milk and ensure the manufacture of high-quality cheese even if technological possibilities are limited.

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