Monitoring Chemical and Microbial Changes of Cottage Cheese using a Full-history Time-temperature Indicator


  • The use of manufacture's name and particular models does not imply endorsement. Financial support from the National Dairy Promotion and Research Board and from the California Dairy Foods Research Center is greatly appreciated.


Cottage cheese (4% milkfat) was stored under three isothermal conditions (3, 9, and 15°C) and one varied temperature condition for the length of its useful shelf life–up to 32 days. Attached to each one-half pint carton were two full history, enzymatic based, time-temperature indicators (I-POINT models #4014 and #4021). Throughout the study quality attributes of the cottage cheese, as determined by chemical and microbial means, and the indicator progress were periodically monitored. The cheese spoiled due to growth of acid-forming bacteria under the warmer conditions and due to psychrotrophic bacteria under the coldest condition. Response of the I-POINT model 4014 was significantly related to changes in three of the quality attributes of the cottage cheese, specifically: pH, standard plate count when the cheese was stored at 8.8° C, and titratable acidity when the cheese was stored at 15.1° C.