1) What is the general storage condition for frozen foods?
Temperature:-18 °C or colder
Relative Humidity: higher RH 90-95%
2) List the various types of frozen foods storage period at -18 °C?
● Packaged chicken, pies, sugared fruits -> Over 12 months
● Beef, veal, lamb, turkey, bakery products -> 10 to 12 months
● Lean fish, shellfish, some fatty fish -> 8 to 10 months
● Fried foods, pork, most dairy products, fatty fish -> 6 or less months
3) What are TTT and their effects?
The degree to which individual products tolerate the time and temperature effects is called the Time-Temperature Tolerance (TTT) and it affects product color, flavor and texture.
4) What is practical storage life of frozen foods?
It means how long certain categories of products can be effectively stored without creating undue quality damage to the products. This storage period is commonly called as “Practical Storage Life (PSL)”.
5) What are the general conclusions pertaining to Practical Storage Life?
a) There is no reason for maintaining freezer storage at -29 °C except unpacked fat fish and some high fat ice cream products
b) The temperature between -23 to -26 °C may be desirable for lean fish and precooked foods to be held over 6 months
c) All other commodities may be stored at -18 °C or colder for more than 1 year
d) Rapid pre-cooling and ultra-rapid freezing are benefits to fruits, vegetables and fat meat and least benefits to lean meats
e) Quality of product entering storage, method of processing and handling, method of packaging are influencing the frozen foods storage life.
6) How to handle the frozen foods?
a) Exposure to elevated temperature (more than storage temperature) is serious for frozen foods causing damage
b) Temperature fluctuations should be avoided will cause migration of moisture from the product or within the package causing formation of ice crystals and partial dehydration of the product
c) Frozen foods are stored at -18 °C or colder, when they are loaded for transport or placed in retail cabinets.
7) What are the effects of thin and thick cases of packaging in cold storage?
If items packed in small thin cases will cool somewhat faster and those in large thick cases will cool somewhat slower time.
● For Concentrated juices and fruit pies (thick cases); if stored at at a temp of -1 °C to -15 °C, it will take 45 hours to freeze
● Other frozen foods (thin cases); if stored at at a temp of -1 °C to -15 °C, it will take 33 hours to freeze
8) What are the steps in taking temperature of frozen foods?
a) Open top of case and remove top corner package
b) Make hole through the case from inside in line with the second layer of product. Use an ice pick or similar tool. Do not use the stem of the thermometer
c) Place the thermometer in the hole from the outside and position of stem 8 cm from the wall
d) Place package back in its normal place and close top of case
e) Place two or more cases on top to assure contact of stem with packages of product
f) Read temperature after 5 minutes
g) Check the accuracy of the thermometer regularly and keep a record of the checks and any re-calibrations.
9) What are the effects of temperature on frozen foods?
a) If the temperature is -3.9 °C or higher – damage to quality is occurring rapidly and immediate steps should be taken to prevent further damage
b) If the temperature is -12 °C or higher, but below -3.9 °C – damage to quality is occurring slowly but at an unacceptable rate and prevent the foods to place at -18 °C condition
c) If the highest temperature is -18 °C – it is satisfactory for most of the products
10) What are the processes in freezing of frozen foods?
a) Pre-freezing-washing, husking, shelling, cutting, boning, trimming, pitting, slicing,inspection and grading
b) Freezing– fluidized bed freezer, IQF freezer
c) Frozen storage – stored at minimum moisture barrier package and particular cold temperature.
11) List the important points to consider inefficient operation of air blast freezing?
a) Air temperature of the freezer should be -23 °C. typically, the temperature is-34 to -40 °C
b) Air velocity should be 1000-2000 ft/min or higher
c) Product should not be transferred to the still-air storage room until the product has attained at -18 °C
d) A stacking arrangement on pallets should be used that enables cold air to contact all cases.
12) What is freezer burn?
It is a term used to describe the surface of frozen poultry, meat, and other products that have dried out because of poor packaging. The surface has a whitish, mottled appearance.
13) List the spoiling organisms cease functioning temperature in frozen foods?
a) Food poisoning organisms and psychotropic organisms cease functioning at just below 0 °C
b) Psychrophilic organisms, which are less common in foods, cease functioning at approximately -10 °C
