Lactobacillus casei

Lactobacillus casei
Lactobacillus casei in a petri dish
Systematics
Department : Firmicutes Class : Bacilli Order : Lactic acid bacteria (Lactobacillales) Family : Lactobacillaceae Genre : Lactobacillus Type : Lactobacillus casei
Scientific name
Lactobacillus casei
( Orla-Jensen 1916) Hansen & Lessel 1971

Lactobacillus casei is a rod-shaped gram - positive bacterium . It belongs to the smaller Lactobacillus species and grows in the form of shorter or longer rods with mostly rounded corners and an average size of 0.9 µm in diameter and 2 µm in length. They are usually found singly or in pairs, less often in short chains.

The optimum growth is around 30 ° C. Different authors state differently whether growth at 15 and 45 ° C is possible. The growth in milk is very slow, the proteolytic activity is high and homofermentative lactic acid fermentation can produce up to 1.5% lactic acid . This creates a mixture of L- and D-lactic acid with a clearly predominant L-shape. You can break down many carbohydrates , including melezitose , but not melibiose and xylose . Gluconate but not glucose can be fermented to lactic acid with gas production.

Medical importance and usage

Lactobacillus casei is one of the bacteria that occurs naturally in the digestive tract of mammals . It has been shown that the consumption of milk products fermented by L. casei can lead to protection against Salmonella typhimurium infections and diarrhea . A positive effect of the uptake of living cultures has not yet been proven. In the vaginal flora plays Lactobacillus casei normally no role and usually occurs only after bacterial vaginosis on at detectable levels.

In cheese production , Lactobacillus casei plays an important role in the production of hard and semi-hard cheeses, but is often not added in a targeted manner, since sufficient bacteria usually get into the milk through contamination during processing. The species can also occasionally occur as a contamination in bottled beverages, where it breaks down the high sucrose concentrations and leads to cloudiness, sediment and loss of quality.

Individual evidence

1. ↑ ^{a b c} Susanne Blüml, Sven Fischer: Manual of filling technology: Basics and practice for filling liquid products . Behr's Verlag, Hamburg 2004, ISBN 978-3-89947-089-5 .
2. ^ ^{A b} Gunther Müller, Herbert Weber: Microbiology of food: Basics . 8th edition. Behr's Verlag, Hamburg 1996, ISBN 978-3-86022-209-6 , pp. 133 .
3. ↑ Bernhard Watzl, Claus Leitzmann: Bioactive substances in food . 3. Edition. Georg Thieme, 2005, ISBN 978-3-8304-5308-6 .
4. ↑ Eiko E. Petersen: Infections in Gynecology and Obstetrics: Textbook and Atlas . 4th edition. Georg Thieme, 2003, ISBN 978-3-13-722904-9 , p. 10 .