654 
Concentrated  Milk  Products. 
(  Am.  Jour.  Pharm. 
(    September,  1920 
at  a  temperature  of  120°  to  130°  F.  until  the  volume  of  liquid  is 
40  per  cent,  or  less  of  the  original  volume;  if  the  milk  be  overheated, 
the  albumin  will  be  coagulated  and  the  sugar  caramelized.  After 
condensation,  the  milk  is  drawn  off  into  cooling  cans  and  constantly 
stirred  in  a  sanitary  room  and  atmosphere  for  two  or  three  hours 
until  a  temperature  of  70°  F.  is  reached,  when  it  is  quickly  canned 
and  sealed. 
Some  of  the  more  modern  canners  of  milk,  sterilize  the  cans  with 
dry  heat  before  filling  them,  but  the  cans  are  cooled  in  vacuo  before 
being  filled,  otherwise  the  milk  congeals.  If  the  milk  condensed 
be  acid,''a  certain  amount  of  invert  sugar  (dextrose  and  levulose) 
is  formed.  Some  manufacturers  use  invert  sugar  in  place  of  cane 
sugar  (U.  S.  D.  20  Edt.,  1498),  because  invert  sugar  has  a  less  sweet 
taste  than  cane  sugar  and  is  less  liable  to  cause  sugar  of  milk  to 
crystallize  in  the  can. 
According  to  Food  Inspection  Decision  No.  170  (U.  S.  Depart- 
ment of  Agriculture,  March  31,  191 7),  condensed  milk  must  be  the 
product  of  the  evaporation  of  whole,  fresh,  clean  cow's  milk  and 
must  contain  at  least  8  per  cent,  milk  fat  and  not  less  than  28  per 
cent,  total  milk  solids. 
Condensed  milk  is  not  sterile  and  may  contain  pathogenic  organ- 
isms; it  is  preserved  against  decomposition  by  its  high  percentage 
of  sugar,  which  also  prevents  freezing  during  transportation.  So 
long  as  the  can  is  unopened,  condensed  milk  will  keep  under  favora- 
ble conditions  for  a  year  or  two,  but  after  several  months  it  becomes 
darker  in  color  and  thicker;  when  the  can  is  opened,  if  kept  in  a 
cool  and  sanitary  place,  it  will  keep  for  several  days. 
Condensed  milk  was  the  first  form  of  canned  milk  put  on  the 
market.  "The  early  French  inventors  along  this  line,  dating  back 
over  a  hundred  years,  are  said  to  have  been  called  forth  by  Napo- 
leon's efforts  to  obtain  a  milk  that  could  be  transported  for  the  use 
of  his  armies.  It  is  interesting  to  note  that  canning  milk  first  be- 
came a  successful  enterprise  because  of  the  urgency  in  this  country 
of  feeding  the  soldiers  of  the  North  in  the  Civil  War."  ("Condensed 
Milk  and  Milk  Powder:"  Otto  F.  Hunziker.  Pubhshed  by  the 
author,  Lafayette,  Ind.,  1914.) 
During  the  recent  World  War,  the  demand  for  condensed^milk 
was  enormous.  Mr.  Charles  B.  Hires,  of  Philadelphia,  one  of  the 
leading  manufacturers  of  condensed  milk  in  the  country ,f writes 
me  as  follows: 
