Frozen food storage. f

Food Processing Technology
Degree and Diploma

1. Storage of Frozen Food products Y.Bavaneethan . Lecturer Department of Food Technology 8/16/2019 Y.Bavaneethan 1

2. Temperature requirements during frozen storage The quality of frozen foods depends; quality of raw materials maintain product temperature at a suitable low level in any part of the cold chain including; storage , transport, distribution, and display in retail stores . 8/16/2019 Y.Bavaneethan 2

3. Frozen foods deteriorate during storage by different mechanisms and low temperatures are required to maintain the food quality. Deterioration is starting by the fluctuating time–temperature environment during storage. The required temperature conditions need to be maintained; the cold chain from the producer to the consumer assuring a temperature of −18◦C – a limit set by the majority of international regulations . A fter quick freezing, T he product should be maintained at−18◦ C or colder after thermal stabilization. Some frozen foods (broilers, beef, butter ) have a fairly long storage life even at −12◦C W hereas foods such as lean fish require storage temperatures around −28◦ C. 8/16/2019 Y.Bavaneethan 3

4. Storage Period Various types of frozen foods have different stabilities in frozen storage depending on many factors including; quality of raw material and product ingredients, processing, and packaging materials. Storage life can be extended significantly as storage temperatures become colder. For most products, a temperature of 0 °F (-18 °C) or below is required if storage is expected to exceed 6 months T emperature-recording device must be installed in each storage facility to register and store for at least a year the temperature data of air surrounding the perishable food. 8/16/2019 Y.Bavaneethan 4

5. Time & Temperature Tolerance (TTT) The integrated effects of time and temperature on frozen foods affect their color, flavor and texture, commonly referred to as quality. The degree to which individual products tolerate the time & temperature effects is called the Time-Temperature Tolerance (TTT ) . Regulations or company quality-assurance standards must specify and control both the time and temperature factors to guarantee product quality. On the other hand , the extreme importance of frozen food quality to consumers makes imperative efforts of all segments of the frozen food industry to prevent conditions that could lead to; product deterioration in any part of the cold chain and consumer dissatisfaction. 8/16/2019 Y.Bavaneethan 5

6. T he temperature of quick frozen food must be maintained at −18◦C or colder at all points of the product, with possible brief upward fluctuations of no more than 3◦C during transport . Storage temperatures can fluctuate significantly over the complete cold chain. Typically, − 23◦C has been the average for the manufacturer’s cold store with a maximum target of no more than −18◦C during fluctuations Fluctuations in storage temperature significantly affect the shelf-life of the product. The three principal kinds of sensors are thermocouples, platinum resistances and thermistors 8/16/2019 Y.Bavaneethan 6

7. The TTI is an accumulated time–temperature distribution function. The perishable product is subjected from the point of manufacture to display on retail outlet, or even to the consumer. The time–temperature integrators show; a physical or a colour change, and an essential condition that is, energy of activation of this device shall coincide with the energy of activation of the frozen food deterioration that means having the same temperature sensitivity. 8/16/2019 Y.Bavaneethan 7

8. If the highest reading is 25°F (- 3.9°C) or higher Quality d amage is occurring rapidly and immediate steps should be taken to prevent further damage. Product should be placed in a blast freezer or rapid freezer with spacers between cases to permit air circulation and rapid temperature drop. Cases should not removed to storage room until product is at 0°F (-18°C) or lower. Product which has been above 25°F (-3.9°C) should be evaluated after it has been returned to 0°F (-18°C) or below. It may no longer have acceptable quality. Even if quality is still acceptable , but remaining shelf life is shortened . 8/16/2019 Y.Bavaneethan 8

9. If the highest reading is 10°F (-12°C) or higher, but below 25°F (- 3.9°C ) Quality damage occurring slowly but at an unacceptable rate. To prevent further damage , it is necessary to place the product in 0°F (-18°C) or lower temperature within an hour . If not done, quality damage can be expected. If the product has risen above 10°F (-12°C), air circulation should be provided between cases. Even if the quality is still acceptable, the product life significantly reduced. 8/16/2019 Y.Bavaneethan 9

10. If the highest reading is 0°F (- 18°C) This temperature is satisfactory for most, but not all, products. most of the products quality achieved after the initial freezing has been retained ( O o F ). If frozen foods a desired low temperature, to prevent air movement between cases to reduce undesired increase in air temperature . If frozen foods are at an undesired high temperature; that needs without delay to preserve the quality , allow to circulation of colder air between cases Other products should be protected during this procedure warming of product under this treatment . 8/16/2019 Y.Bavaneethan 10

11. Practical Storage Life (PSL ) of Frozen food P roducts can be effectively stored without creating undue quality damage to the products. This storage period is commonly called the Practical Storage Life (PSL), or shelf life. For any specific frozen product, product characteristics (raw materials, ingredients, formulation ) initial quality of the original foodstuff prefreezing treatment freezing process packaging film, and storage temperature. 8/16/2019 Y.Bavaneethan 11

12. The shelf-life of a frozen food can be extended through; ingredient selection, process modification and change of package or storage conditions . High-quality life parameter (HQL) is defined as; t he storage period - initial quality was maintained from the time of freezing up to the point N oticeable difference between the frozen food stored at different temperatures. C orresponding controls stored at −40◦C in a triangular sensory test therefore this parameter is also known as Just Noticeable Difference (JND). 8/16/2019 Y.Bavaneethan 12

13. Raw and pre-cooked lean meat at 5 °F (-15 °C) may be stored between 4 and 20 months, depending on the initial quality, processing method and packaging material. However, at -4 °F (-20 °C) the range increases to between 8 and 33 months. At temperatures of -22 °F (-30 °C) the potential storage period increases to between 20-33 months. 8/16/2019 Y.Bavaneethan 13

14. Raw and pre-cooked fatty meat products have shorter storage ranges than lean meat, The high fat content can result in oxidative rancidity and off flavors, thereby reducing the practical storage life by about half when compared to lean meats. Fat fish products are the most sensitive protein group to quality deterioration during frozen storage. This is due to the high level of unsaturated fatty acids which can easily become rancid or off condition over time in storage. 8/16/2019 Y.Bavaneethan 14

15. The following are general conclusions to Practical Storage Life: There is no reason for maintaining freezer storage at -20 °F (-29 °C) for any commodities except for unpackaged fat fish and some high-fat ice cream products. A temperature of -10 to -15 °F (-23 to -26 °C) may be desirable for lean fish and precooked foods without gravy if they held for well over 6 months in storage. All other commodities may be stored at 0 °F (-18 °C) or colder even if they are to be held for longer than 1 year. Rapid pre-cooling and ultra-rapid freezing are of particular benefit to fruits, vegetables, and fat meats, and of least benefit to lean meats. 8/16/2019 Y.Bavaneethan 15

16. Quality of product entering storage, method of processing and handling, and method of packaging have a profound influence on storage life of the frozen product. should be aware of these pre-storage conditions quality deterioration during storage 8/16/2019 Y.Bavaneethan 16

17. Packaging of frozen food Packaging plays a key role in protecting the frozen product from; contamination by external sources and damage during its passage from the food producer to the consumer. The key functions of food package are: protection, preservation and presentation. Protection is necessary to prevent the following: external biological contamination dehydration caused by moisture loss and freeze burn oxidation of lipids, flavours , colours and vitamins loss or gain of aromas physical damage (abrasion, fracture and compression) 8/16/2019 Y.Bavaneethan 17

18. Frozen food packaging materials must be able to withstand low temperatures of −25◦C to −30◦C and , sometimes high temperatures, such as microwave and boil-in-bag products. The materials must be; chemically inert nontoxic and prevent the transfer of foreign odours or flavours . must be stable, elastic, tear-resistant, and proof against water vapour and volatile substances. 8/16/2019 Y.Bavaneethan 18

19. The alterations and losses in aroma and flavour , enzymatic browning and oxidation of ascorbic acid that take place in the presence of oxygen packaging materials should be used that are impervious to oxygen or permit removal of the oxygen from inside the package either by creating a partial vacuum or by injecting inert gases . They must also offer protection against light, particularly UV rays . Packages should be effective as, thermal insulators to limit possible temperature fluctuations within the product . 8/16/2019 Y.Bavaneethan 19

20. The materials most commonly used for frozen food packaging include paperboard that have poor barrier properties but good structural resistance and provide protection against physical damage plastic materials with excellent moisture, oxygen and aroma barriers semi-rigid plastic containers that have good structural properties aluminium that is a total barrier to moisture, oxygen, and aroma . low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP ): these are excellent moisture barriers but have poor oxygen barrier properties. polyvinylidene chloride (PVDC)/polyvinyl chloride (PVC) copolymer that are excellent moisture , oxygen and aroma barriers . 8/16/2019 Y.Bavaneethan 20

21. ethylene vinyl alcohol (EVOH) copolymer and polyamide (Nylon) with poor moisture barrier properties and excellent oxygen and aroma barrier properties polyethylene terephthalate (PET), with good moisture, oxygen and aroma barrier and good heat resistance; the heat resistance is even greater in crystallised polyethylene terephthalate (CPET ). For packaging frozen fish, PVDC is used in vacuum packaging. This system provides a better alternative to glazing process. It eliminates moisture loss on initial freezing, drip loss on thawing weight loss on glaze. 8/16/2019 Y.Bavaneethan 21

22. The majority of frozen fruits and vegetables are packaged in plastic films, such as deep freeze grades of PE Vegetables are packaged commonly with LDPE as moisture barriers. Ethylene vinyl acetate (EVA ) bags have mechanical resistance for large weights of product with the necessary moisture barrier , have good heat-seal properties, and remain flexible at freezer temperatures 8/16/2019 Y.Bavaneethan 22

23. THANK YOU 8/16/2019 Y.Bavaneethan 23