FAMILY LACTOBACTERIACEAE 



355 



are never fermented. Earl}^ workers 

 (Gigoroff) (Cohendy) noted fermenta- 

 tion of fructose, maltose and sucrose. 

 Later workers (Bertrand and Duchacek) , 

 (Orla-Jensen), (Rahe), (Kulp and Rett- 

 ger), (Sherman and Hodge) noted vari- 

 able or negative results on sucrose, mal- 

 tose and unheated fructose. 



Forms high acidity in milk. The 

 lactic acid is inactive (Grigoroff), (Ber- 

 trand and Duchacek), (White and Avery) 

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

 with small quantities of volatile acid 

 (White and Avery). 



Aerobic or anaerobic (Luerssen and 

 Kiihn). jNIicroaerophilic (White and 

 Avery). Anaerobic in fresh isolation 

 (Sherman and Hodge). 



Optimum temperature 45° to 50°C. 

 Minimum 22°C (Luerssen and Kiihn). 



Distinctive characters: This species 

 at present is regarded as including the 

 high temperature organisms isolated 

 from milk with difficulty. These fer- 

 ment glucose, galactose and lactose but 

 usually do not ferment sucrose, maltose 

 or unheated fructo.«e when freshly iso- 

 lated. 



Source : Originally isolated from yog- 

 hurt. 



Habitat : Probably present in many 

 milk products if held at high tempera- 

 ture. 



7. Lactobacillus thermophilus Ayers 

 and Johnson . (Jour. Bact .,9, 1924, 291 . ) 

 From Greek thermos, heat and philus, 

 loving. 



Description of Ayers and Johnson 

 supplemented by material from Charlton, 

 Jour. Dairy Sci., 15, 1932, 393. 



Rods: 0.5 by 3.0 microns. Stains 

 irregularly. Xon-motile (Charlton). 

 Gram-positive. 



Gelatin stab: Xo liquefaction. 



Agar plate: Small colonies. 



Agar slant: Slight, translucent growth 

 (Charlton). 



Broth: Turbid (Charlton J. 



Litmus milk: Acid. 



Nitrites not produced from nitrates 

 (Charlton). 



Acid from glucose, lactose, sucrose, 

 starch and trace from glycerol. No 

 acid from salicin, mannitol, raffinose or 

 inulin. (Ayers and Johnson). Acid 

 from fructose, galactose, mannose, mal- 

 tose, raffinose and dextrin. No acid 

 from arabinose, xylose, glycerol, rham- 

 nose, salicin, inulin or mannitol. Dextro 

 lactic acid formed. (Charlton). 



This is the thermophilic lactobacillus 

 obtained from pasteurized milk which 

 causes pin-point colonies on agar plates. 



Temperature relations: Optimum tem- 

 perature 50° to 62.8°C. Minimum 30°C. 

 Maximum 6o°C. Thermal death point 

 71°C for 30 minutes or 82°C for 2^ 

 minutes. 



Facultative anaerobe. Grows best 

 aerobically. 



Source: From pasteurized milk. 



Habitat : Known only from pasteurized 

 milk. 



8. Lactobacillus delbrueckii (Leich- 

 mann) Beijerinck. {Bacillus delbruckii 

 Leichmann, Cent. f. Bakt., II Abt., 2, 

 1896, 284; Bacillus acidificans longissi- 

 mus Lafar, Cent. f. Bakt., II Abt., 2, 

 1896, 195; Bacillus (?) acidificans Migula , 

 Syst. d. Bakt., 2, 1900, 801; Beijerinck, 

 Arch, neerl. d. sci. exactes et nat., 

 Hadrlem, Ser. 2, 7, 1901, 212; Thermo- 

 bacterium cereale Orla-Jensen, The Lactic 

 Acid Bacteria, 1919, 164; Bacillus acidi- 

 ficans -longissimus Holland, Jour. Bact., 

 5, 1920, 216; Lactobacillus acidificans- 

 longissimns Holland, ibid., 216; Lacto- 

 bacillus cereale Holland, ibid., 223; 

 Lactobacterium delbrucki (sic) van Steen- 

 berge, Ann. Inst. Past., 34, 1920, 820.) 

 Named for Prof. M. Delbriick, German 

 bacteriologist. 



Description of Leichmann supple- 

 mented 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 

 (Henneberg), occurring singly and in 

 short chains. Non-motile. Gram-posi- 

 tive. 



