FAMILY X. LACTOBACILLACEAE 



547 



Colonies: Flat, yellowish white, 2 to 3 

 mm in diameter. Old cultures have dark 

 centers. Deep colonies globular (Luerssen 

 and Kiihn). 



Whey agar colonies: Circular to irregular 

 (White and Avery). 



Milk: Coagulation at 37° C. No gas. No 

 decomposition of casein. 



Potato: Yellow-white colonies (Luerssen 

 and Kiihn). No growth (Grigoroff), (Co- 

 hendy), (White and Avery). 



Indole not produced (Grigoroff), (White 

 and Avery). 



Results on acid production from sugars 

 vary. Glucose, lactose and galactose are 

 apparently always fermented while xylose, 

 arabinose, sorbose, rhamnose, dulcitol, 

 mannitol, dextrin, inulin and starch are 

 never fermented. Early workers (GigorofT) 

 (Cohendy) noted fermentation of fructose, 

 maltose and sucrose. Later workers (Ber- 

 trand and Duchacek), (Orla-Jensen), 

 (Rahe), (Kulp and Rettger), (Sherman and 

 Hodge) noted variable or negative results 

 on sucrose, maltose and unheated fructose. 



Forms high acidity in milk. The lactic 

 acid is optically inactive (Grigoroff), (Ber- 

 trand and Duchacek), (White and Avery) 

 or levo rotatory (White and Avery), (Orla- 

 Jensen) with small quantities of volatile 

 acid (White and Avery). 



Nitrites not produced from nitrates. 



Aerobic or anaerobic (Luerssen and 

 Kiihn). Microaerophilic (White and Avery). 

 Anaerobic in fresh isolation (Sherman and 

 Hodge). 



Temperature relations: Optimum, be- 

 tween 45° and 50° C. Minimum, 22° C. (Lu- 

 erssen and Kiihn). 



Distinctive characters: This species at 

 present is regarded as including the high- 

 temperature organisms isolated from milk 

 with difficulty. These ferment glucose, ga- 

 lactose and lactose but usually do not fer- 

 ment sucrose, maltose or unheated fructose 

 when freshly isolated. 



Source: Originally isolated from yogurt. 



Habitat: Probably present in many milk 

 products if held at high temperature. 



7. Lactobacillus iherniophilus Ayers 

 and Johnson, 1924. (Jour. Bact., 9, 1924, 

 291.) 



ther.mo'phi.lus. Gr. noun therme heat; 

 Gr. adj. philus loving; M.L. adj. thermo- 

 philus heat -loving. 



Description of Ayers and Johnson sup- 

 plemented by material from Charlton (Jour. 

 Dairy Sci., 15, 1932, 393). 



Rods 0.5 b}- 3.0 microns. Non-motile 

 (Charlton). Stain irregularly. Gram-posi- 

 tive. 



Gelatin stab: No liquefaction. 



Agar plate: Small colonies. 



Agar slant: Slight, translucent growth 

 (Charlton). 



Broth: Turbid (Charlton). 



Litmus milk: Acid. 



Acid from glucose, lactose, sucrose, starch 

 and trace from glycerol; no acid from sali- 

 cin, mannitol, raffinose or inulin (Ayers and 

 Johnson). Acid from fructose, galactose, 

 mannose, maltose, raffinose and dextrin; 

 no acid from arabinose, xylose, glycerol, 

 rhamnose, salicin, inulin or mannitol. Dex- 

 tro rotatory lactic acid formed (Charlton). 



Nitrites not produced from nitrates 

 (Charlton). 



Facultatively anaerobic. Grows best aer- 

 obically. 



Temperature relations: Optimum, be- 

 tween 50° and 62.8° C. Minimum, 30° C. 

 Maximum, 65° C. Thermal death point, 

 71° C. for 30 minutes or 82° C. for 2^ min- 

 utes. 



This is the thermophilic lactobacillus ob- 

 tained from pasteurized milk which causes 

 pin-point colonies on agar plates. 



Source: Isolated from pasteurized milk. 



Habitat: Known only from pasteurized 

 milk. 



8. Lactobacillus delbrueckii (Leich- 

 mann, 1896) Beijerinck, 1901. {Bacilhis del- 

 hriickii Leichmann, Cent. f. Bakt., II Abt., 

 2, 1896, 284; Beijerinck, Arch, n^erl. d. sci. 

 exact, et nat., Hadrlem, S4r. 2, 7, 1901, 212.) 



del.bruec'ki.i. M.L. gen. noun delbrueckii 

 of Delbriick; named for Prof. M. Delbriick, 

 a German bacteriologist. 



Description of Leichmann supplemented 

 by material from Henneberg (Cent. f. Bakt., 

 II Abt., 11, 1903, 154). 



Rods, 0.5 to 0.8 by 2.0 to 9.0 microns (Hen- 

 neberg), occurring singly and in short 

 chains. Non-motile. Gram-positive. 



