RED COLORATION IN MILK. 14 r 



between the lines D and E and a third in the blue. A species of 

 fission fungus allied to B. lactis erythrogenes has been isolated from 

 red milk by A. BAGINSKY (I.). 



Of the sarcina group two species are known to be endowed 

 with the faculty of reddening milk. One of these was discovered 

 by K. MENGE (II.), viz. Sarcina rosea Menge; and the second 

 was isolated from red milk by L. ADAMETZ (II.), and was identified 

 with the Sarcina rosea Schroeter, very frequently met with in the 

 air. Apart from the red coloration, Menge's sarcina produces no 

 noteworthy changes in milk, but Schroeter's sarcina, on the other 

 hand, first precipitates the casein which is subsequently gradually 

 re-dissolved. Consequently a milk-culture (growing dark brown 

 in colour) kept at 25 C. for four to five weeks no longer exhibits 

 any deposit beyond a sediment consisting of sarcina packets. 



Red coloration in cheese may arise from various causes, those 

 of a purely chemical nature being merely referred to here for the 

 purpose of differentiation. According to the researches of H. 

 BURSTERT and F. J. HERZ (I.), a number of rhodanate (thiocyanate) 

 compounds develop in ripening curd, and when the ripe cheese is 

 cut the iron compounds therein oxidise and combine with the 

 thiocyanates, the resulting ferric thiocyanate being in sufficient 

 quantity to impart a red or reddish tinge to the cut surface. A 

 sample of cheese thus reddened is decolorised by immersion in 

 a solution of oxalic acid, so that this reagent should be employed 

 in doubtful cases. If, on the other hand, micro-organisms are at 

 work, the result is different. This disagreeable phenomenon is 

 more rarely encountered in hard than in soft cheeses. Red spots 

 gradually form on the surface and spread by degrees, but do not 

 penetrate more than a few millimetres into the substance of the 

 cheese. The spots may be composed of red Ewnycetes or of 

 pigment bacteria. ADAMETZ (III.) isolated two species of micro- 

 coccus from red cheese, both of which develop a red colouring 

 matter in milk and cheese; but more frequently Eumycetes, i.e. 

 higher fungi, are the cause of this phenomenon in cheese. These 

 will be discussed in a subsequent section. 



The cause of the reddening of dried codfish (stock-fish) was 

 investigated by LE DANTEC (L). About one- third of this article 

 put on the market is said to be affected by this evil, and is 

 thereby rendered unsaleable, not only by reason of its salmon 

 colour, but also because of a popular belief that reddened stock- 

 fish is poisonous. The annual loss thus entailed is estimated at 

 ten millions of francs (,400,000). Le Dantec isolated three 

 organisms from such spoiled fish ; the first being a sporogenic red- 

 producing bacillus, morphologically similar to tetanus bacillus, and 

 liquefying gelatin ; secondly, a coccus of 3-5 ^ diameter, develop- 

 ing on gelatin to solid red colonies, but not producing a red 

 colouring matter in the fish unless accompanied by a second 

 species of coccus, which, by itself, is incapable of developing 



