Executive Summary
The ice cream industry is a fast-growing and successful industry in many countries. To remain successful, effective cold chain management is needed at every stage of its production and delivery. The main purpose of this research paper is to explore cold chain logistics applicable to ice cream manufacturing. The first section of the project will introduce the readers to the product and briefly describe its origin and main ingredients. After that, an overview of the quality and safety standards in chilled and frozen products will be made. The most important sections will focus on the temperature management, temperature abuse, and shelf-life of ice creams. The role of good packaging will also be discussed in the paper. Finally, Singapore’s legal requirements for the cold chain management of ice cream will be listed at the end of the project.
The main method of data gathering was a literature review. The author reviewed many scholarly articles, websites, and legal documents to find all the necessary information about the cold chain management of ice creams. Research showed that different standards have different requirements for freezing, storing, handling, and transporting this perishable product. However, it is internationally agreed that it should never be allowed to freeze, store, and hold ice cream at a temperature higher than –18°C. The legal requirements for packaging are also similar. Most countries recommend using packages made of safe materials and indicate the most important information on them. However, the shelf life is usually not mentioned in the container because it depends on various factors. The main recommendation for processing, handling, transporting, and storage of ice cream is to provide strict temperature control at each stage and not allow temperature fluctuations.
Introduction
Ice cream is a frozen dairy product produced through freezing milk, condensed milk, or cream with other additives. This perishable product also contains such ingredients as sweeteners, colors, flavors, stabilizers, as well as nuts, chocolate, fruits, candy pieces, and egg products (Deosarkar et al., 2016). Ice cream originates from Europe, but it came later to the United States, where the ice cream industry began (Deosarkar et al., 2016).
Nowadays, the ice cream industry is a growing sector in the food industry. Its success depends on the effective management of the cold chain. If every step, beginning with ice cream production and ending with the delivery to consumers, is under control, the success of this industry will continue. Thus, it is vital to control the cold chain to preserve the quality and safety of such a perishable product as ice cream and comply with all legal requirements. This practical guide will focus on the main recommendations for the production, temperature management, freezing, temperature abuse and monitoring, packaging, and delivery of ice cream.
Quality and Safety in Chilled and Frozen Foods: An Overview
To ensure the quality and guarantee the safety of chilled and frozen foods, an uninterrupted cold chain should be preserved in this industry. In the cold chain, temperature conditions are the key factor impacting the quality and safety of the final product. It is of high importance to preserve low temperature to minimize the risk of foodborne diseases, maintain the quality of a chilled or frozen product, and eliminate the growth of spoilage-causing bacteria (Wu & Hsiao, 2020).
In different countries, the regulations for temperature requirements may be diverse. For example, in the United States, the temperature of chilling must be colder than 4°C, and the temperature of freezing must be lower than –18°C (Wu & Hsiao, 2020). In Japan, these temperatures must be colder than 10°C and –15°C, respectively (Wu & Hsiao, 2020). In any case, all these regulations and requirements are aimed to increase the quality of a chilled or frozen product and guarantee its safety for the consumers.
The cold chain process begins when the supplier provides the raw material for the product and ends when the customer brings the product to their refrigerator. There are several factors that should not be ignored during the cold chain process. Thus, the suppliers, manufacturers, and sellers should preserve hygiene at each stage of the product’s existence. Products should be chilled or frozen rapidly and properly right after their manufacture.
Ice cream is a perishable frozen product, so it should not be chilled. The quality of ice cream depends on production and storage. One of the factors influencing the quality of ice cream is ice crystal size (Buyck et al., 2011). At the beginning of the freezing process, ice crystals appear.
Heat is removed quickly during the freezing process, and the air is incorporated into ice cream to achieve a smooth and soft texture (Buyck et al., 2011). The size of ice crystals depends on the speed of the freezing process: the faster it is, the smaller the ice crystals will be in the product. Consequently, the quality of ice cream will be much better, and the product will be more desirable for the customers since it will be less icy. However, some other factors may influence the size of ice crystals. For example, low freezing point, low solids content of the additives, long storage time, insufficient stabilizer, high draw and storage temperature, and some other factors may result in iciness of the final product.
Temperature Management
Ice crystals will grow when ice cream warms because some crystals will melt and attract water to other crystals, thus creating bigger ice crystals. If the ice cream is stored at –5°C, recrystallization will be inevitable (Buyck et al., 2011). Moreover, if the amount of solid contents increases to 34-38 percent, recrystallization will also occur rapidly (Buyck et al., 2011). Fat has a great impact on the ice cream texture too. It decreases the size of ice crystals and produces a lubricating effect. Ice cream with a higher content of fat seems smoother and less icy than light or fat-free ice cream.
Microbiological Safety
Since ice cream is a milk product, it is also a good place for microbial growth. Moreover, any of the ice cream ingredients may also “contribute microorganisms and affect the quality of the product” (Mohammed et al., 2019, p. 111). Such pathogens like “Listeria monocytogenes, Salmonella species, Staphylococcus aureus, Yersinia enterocolitica and Bacillus cereus” may appear in the ice cream at different stages of its production, delivery, and storage (Saudi et al., 2013, p. 2193). Hazard Analysis and Critical Control Point (HACCP) was created to control the microbiological safety and quality of the ice cream (Saudi et al., 2013).
Hazard analysis is essential for identifying and assessing the ice cream production process and outlining chemical, biological, and physical characters that may affect the product’s quality and safety (Lu et al., 2014). Ice cream production may have quality and safety hazards at each level of its technical process.
The main principles of HACCP involve:
- identifying potential hazards,
- determining the critical control points (CCPs),
- identifying actions needed to control the CCPs.
In the case of ice cream production, it was determined that the main CCPs are pasteurization and freezing (Lu et al., 2014). On the stage of pasteurization, there is a hazard of living pathogens left in the product. Therefore, it is important to keep pasteurization temperature at 80-85°C and maintain it for 15 minutes (Lu et al., 2014). At a freezing stage, there is a risk of pathogen contamination and growth. Thus, processing should be located at “clean operation area, 55-60°C, 3% sodium hydroxide wash, on: pipe entrance and inner wall, vat. 93°C, water wash for 10-15 min.” (Lu et al., 2014, p. 394). If the plant has some problems with any of these issues, they should be modified accordingly to minimize the quality and safety hazards.
Extended Quality Shelf Life
Adhering to the main principles of HACCP may help extend the quality shelf life of the ice cream. However, the ice cream usually does not have a shelf life, so it is important to assess it with the help of accelerated testing (Park et al., 2018). This type of testing allows the assessment of microbiological and sensory conditions of the ice cream and the changes in pH. Research showed that the shelf life of ice cream was “24.27 months at –18°C, 2.29 months at –6°C, 0.39 months at –1°C, and 0.15 months at 4°C” (Park et al., 2018, p. 1222). Although these results cannot be applied to all ice creams, they can be used as basic data to establish the shelf life of ice creams.
Temperature Control and Retention of Nutrients
One can see that proper storage is important for the successful marketing of such a perishable product as ice cream. Moreover, conditions under which it is produced at a factory and held in transit and in sales outlet are also essential for the quality of this frozen product. The International Dairy Foods Association (2021) recommends storing ice cream at –18°C or cooler and not admitting the supermarket’s freezer temperature to be above –12°C. Otherwise, the product will be spoiled, and it should not be sold to the customers. Similarly, if the storage temperature is higher than –28.9°C, the ice cream will be damaged too, and its quality will suffer significantly (Buyck et al., 2011). Thus, it is vital to preserve an optimal temperature at each stage of ice cream production, transportation, and storage.
Temperature control is essential for the retention of nutrients in the ice cream. Moreover, the fortification of ice creams with nutrients has a positive impact on their emulsion stability (Sikdar et al., 2020). Ice cream can be enriched with anti-oxidants, fish proteins, dietary fibers, and other minerals and trace elements. However, with the increase of storage life or errors at any stage of manufacture, the nutrition incorporated in the product might be lost (Sikdar et al., 2020). Therefore, it is highly important to preserve the temperature regime, not extend shelf life, and control every stage of ice cream production to maintain its nutrition value and quality.
Freezing Foods for Optimum Quality
Since ice cream is a frozen product, it cannot be preserved without freezing. The quality of ice cream depends on many factors, including the choice of raw materials, proper pre-freezing processes, choice of a freezer and freezing temperature, storage options, and package choice. The freezing of ice cream is conducted in two stages: dynamic and static. During the dynamic freezing, the mix of ice cream components is frozen quickly while being stirred to saturate with air and minimize the size of ice crystals (Masuda et al., 2020). Static freezing is a rapid method of heat removal, and it occurs without agitation.
Dynamic freezing is more important because it does not change the microstructure of the ice cream, as static freezing does. The ice cream mix is introduced to the freezer at 25°C, and the agitation process begins and continues for 25 minutes without freezing (Masuda et al., 2020). After that, the mixture is cooled below its freezing temperature (–5°C), and the process of aging begins at –4°C and continues from 4 to 24 hours (Giudici et al., 2021). The second freezing step occurs at –25/ –30°C, and during this stage, a harder texture and longer shelf life are achieved (Giudici et al., 2021). If any of these temperature regimes are violated, the ice cream quality and safety will be affected.
Temperature Abuse and Shelf Life of Ice Cream
As is has already been mentioned, temperature control is essential for high-quality ice cream production and storage. The International Dairy Food Association states that if the temperature of ice cream storage is higher than –28.9°C, the product should not be sold at retail due to an incurred heat shock (Buyck et al., 2011). Temperature abuse during storage and delivery affects the chemical and physical characteristics of the ice cream negatively. For example, during storage, temperature fluctuations may be 2-3°C, while during transportation, the temperature may increase by 3-8°C (Leducq et al., 2015). As a result, the size of ice cream crystals increases while their quality and shelf life decreases.
Air cell structure will also change if the storage temperature is abused. Appropriate air cell structure guarantees that the ice cream will have a light texture and proper melting features. The mean diameter of air cells is 40 μm, demonstrating a high-quality product (Park et al., 2015). However, when the temperature is higher than –25°C, these cells will accrete to bigger cells, and the structure of the ice cream will coarsen (Park et al., 2015). As a result, the product’s quality will worsen, and its shelf life will be reduced.
As it was already mentioned, there is no law that regulates the shelf life of ice cream. In the United States and some European countries, it is not mandatory to indicate an expiration date on an ice cream package (Park et al., 2018). However, temperature abuse during pasteurization may lead to the growth of microbes and bacteria, which will continue to grow during improper storage (Park et al., 2018).
For example, Listeria monocytogenes was found in many ice creams in the United States and led to numerous foodborne outbreaks (Park et al., 2018). Accelerated shelf-life tests showed that the physical and chemical characteristics of ice cream samples reached their limit after 24.27 months under –18°C (Park et al., 2018). The higher the storage temperature was, the shorter the shelf life would be. One can see that it is crucial to control the temperature at each stage of the cold chain of ice cream to preserve it fresh, tasty, and healthy.
The Role of Ice Cream Packaging in the Cold Chain
The primary function of packaging is to protect the ice cream from damage and contamination during its storage and transporting. Moreover, a package must contain information about the ingredients, nutritional value, serving suggestions, and other useful data (Deosarkar et al., 2016). A good package preserves the ice cream quality, allowing it to remain the same from the moment of its manufacture to the delivery. Ice cream packages may be subjected to shock, vibration, compression, and heat shock during distribution (Deosarkar et al., 2016). If the quality of a package is good, the ice cream will be protected from short-time temperature changes, dehydration, extraneous odors, and photooxidation (Deosarkar et al., 2016). Thus, a good package protects the ice cream from outer factors and preserves its quality.
In addition, the packaging is important for the ice cream hardening process. During the manufacture, the package is used as a container, in which the ice cream is being hardened to a finished product. Containers are usually made of different materials, but plastic and paper are most frequently used. The role of such containers is to give the ice cream a desired form and size and make it convenient to store and transport. An ideal package will not impact the quality of the ice cream, prevent it from melting, protect it from contamination, and preserve its size and form. Moreover, packaging should be safe and stable over the low-temperature range. Recoverable and reusable packages will attract more customers and create a positive brand image. One can see that packaging plays an important role in the ice cream cold chain.
Real-Time Temperature Monitoring Technology in the Ice Cream Cold Chains
Real-time temperature monitoring technologies are used to control the temperature of food products at different stages of their cold chain. Such tracking systems help preserve safe temperature conditions during the transportation process. Real-time temperature monitoring is more important for highly decaying products, such as meat, poultry, dairy and milk, seafood, as well as non-food products, such as vaccines and other pharmaceuticals. Since ice creams are not a highly decaying product, real-time temperature tacking is not so important. It can be used during the transportation and delivery processes to prevent the product’s melting and wastage and minimize the risk of its quality.
At the same time, real-time temperature monitoring may be used if the production plant has outdated equipment and often experiences temperature fluctuations. In such cases, remote temperature monitoring may help save the manufacture from losses. Nevertheless, even if an ice cream plant is equipped with the most modern freezers and thermometers, real-time temperature monitoring technologies will reduce maintenance costs and ensure the high quality of the product.
Singapore Legal Requirements for the Ice Cream Cold Chain Management
The Singapore standards for cold chain management of chilled and frozen food are aimed to guarantee the safety and high quality of these products. However, these standards do not regulate the cold chain management of ice cream. General legislative requirements related to the cold chain management of frozen products include:
- SS 668: 2020 Cold chain management of chilled and frozen foods:
- sets out the General Requirement and Code of Practice for the management of chilled and frozen food (New Singapore Standards, 2021);
- establishes policies, technical and organizational requirements needed to preserve appropriate cold chain management process.
- The Australia New Zealand Food Standards Code.
- State and Territory Food or Health laws.
- Australian Cold Chain Guidelines:
- Contains the recommendations from the legislative documents mentioned above;
- Is aimed to preserve food quality and safety “as they are handled, transported, and stored” (Australian Cold Chain Guidelines, 2017, p. 5).
Some of these legal regulations will be listed further. Thus, Section 3.2 of the Australian Cold Chain Guidelines 2017 strongly recommend to transport, store, and handle frozen products, including ice cream, at temperature never warmer than –18°C. Section 3.6 reviews the problem of heat transfer on the example of ice cream. According to this section, ice cream should preferably be stored between –22°C and –30°C (Australian Cold Chain, 2017, p. 12). The Guidelines explain why it is important to preserve the temperature not higher than –18°C during the handling and storage processes.
Section 4.2 of the Guidelines strictly recommends that the maximum out of refrigeration time limit must be 60 minutes (Australian Cold Chain, 2017, p. 13). However, this recommendation is only applied when the ice cream is unloaded and dispatched at +5°C to +15°C air-conditioned temperature zone. If the temperature is 0-+5°C, the time limit is extended to 90 minutes (Australian Cold Chain, 2017, p. 13). Finally, the Guidelines recommend to load ice cream last and unload it first direct from and to the freezer. The maximum time limit for unloading or dispatching ice cream in usual conditions is 20 minutes (Australian Cold Chain, 2017, p. 14). Other recommendations are general and can be applied to different frozen products.
References
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