The Ultimate Guide to Modern Dairy Storage: From Farm to Table

India is the largest milk producer in the world and contributed about 24% to global milk production in 2021—22. In the last eight years, milk production has increased by over 51%, indicating the need for significant infrastructure in chilling, processing, and logistics. Undoubtedly, modern dairy storage has been a complex process that ensures the quality and safety of dairy products. It involves various stages, including collection, processing, packaging, transportation, and distribution. In this comprehensive guide, we will explore all these aspects involved in getting the milk from the farm to the table. 

Dairy Industry in India: Status and Schemes 

The dairy market is expected to reach $314 billion by 2026, opening gates for new opportunities and investments. The following are some important growth drivers for the industry in India. 

• Rapid Urbanization: The increasing rate of urbanization, from 34% to 37% by 2025 will have a significant impact on consumer habits. There is an inclination towards convenience and packaged products including dairy products.  
• Higher Disposable Income: The increase in per capita disposable income from $1381 in FY 16 to $1981 in FY 20 at a CAGR of 7.5% has increased demand. Higher disposable income allows consumers to spend more on premium and value-added dairy products.
• Supportive Government Policies: Investor-friendly government schemes like Animal Husbandry Infrastructure Development Fund (AHIDF), and Dairy Infrastructure Development Fund (DIDF) have been introduced to accelerate growth in the dairy sector. 
• Stringent Quality Standards: The FSSAI (Food Safety and Standards Authority of India) has harmonised/ aligned its guidelines with global standards.
• Growing Consumer Base: The proportion of Indians in the age group of 15-65 years increased from 55.4% in 1991 to 67.5 % in 2022. Additionally, the Indian median age is 28.4 years and this growing and young population segment has higher disposable income in hand. 

How Does the Milk Get from the Farm to the Store 

Although depending on the business the steps may vary, a typical process may include the following steps. 

• Rearing: Cattle-rearing practices for milk production vary from farm to farm. 

• Harvesting: Milk can be harvested either using hand milking or machine milking. 

• Storing: Milk is usually stored in storage vats or silos that are refrigerated. They come in various shapes and sizes. On the farm, milk is usually stored at around 4 °C or colder, for up to 48 hours. 

• Transportation: Every 24 to 48 hours, milk is collected from the farm in specialized trucks with stainless steel bodies. These are highly insulated to ensure that milk remains cold while being transported to the processing factory. 

• Lab testing: Milk samples are tested for a variety of parameters including bacteria count, milkfat, protein, bulk milk cell count, etc. 

• Processing: Once approved after testing, milk is pasteurised, homogenised, and sent for further processing to create value-added dairy products. 

• Packaging: Milk is packed and sealed in cartons, plastic jugs, etc. 

• Selling: The milk is ready for selling and is stored in refrigerated rooms until delivery to the stores. 

Step-By-Step Process: Best Practices and Industry Standards

In the subsequent sections, we will dive deeper into significant steps. Let’s get started. 

1.Chilling or Cooling of Raw Milk at the Farm or Chilling Centres 

Milk naturally contains microorganisms when harvested from the udder. The microbial growth accelerates between 20 and 40 °C, causing acidity, off-flavours and deterioration in quality. Therefore, to maintain quality, instant chilling or cooling to 5°C or lower is recommended until further processing. 

Here are some of the common methods of cooling. 

• In-can or can immersion
• Surface cooler
• In-tank or bulk tank cooler
• Plate cooler
• Jacketed/vat tank
• Internal tubular cooler

2. Reception of Milk at the Milk Plant 

Usually, the milk is delivered in cans or tankers to the plant. It is required that the milk be graded, emptied, measured by weight/volume, sampled, and bulked to ensure continued supply. The quality of milk being received depends on the health of the cows, the farm practices, collection utensils used, prompt colling, colostrum-free, refrigerated transportation, etc. The operations at the milk plant during receiving can be further categorised—unloading, grading, sampling, weighing, and testing. 

Image source: Pashudhan

3. Storage of Milk

Milk storage is necessary to maintain the milk at lower temperatures to avoid any deterioration in quality before processing. It facilitates the bulking of the raw milk to ensure consistent composition. Moreover, storage ensures uninterrupted processing and bottling operations and ensures the standardisation of milk.  

Storage tanks are used for storing raw, pasteurised, and processed dairy products in large volumes. These tanks should be insulated or refrigerated to maintain the desired temperature during the holding period. These tanks should also facilitate sanitation (circular-cleaning method). Ensure that agitation is maintained enough for homogenous mixing but not lead to churning or air addition. 

Here are some options for storage of milk. 

• • Insulated or refrigerated: Insulating materials are present between the inner and outer linings of the container and a cooling liquid moves between these layers to maintain the temperature. Another alternative is a cold wall tank. 
  • Horizontal or vertical: Vertical tanks find more practical usage due to the modern circular cleaning method.

• Oval or rectangular cylindrical: The primary disadvantage is the presence of dead corners during agitation. 

• Suitable for gravitational flow, air pressure, or vacuum operation: The gravitational flow is the most common. Sometimes, air pressure can be used to extract the product. 

The storage needs to be built stronger than what is usually required for normal operations that rely on gravity flow or atmospheric pressure.

A typical storage tank consists of the sight glass, light glass and lamp, ladder, manhole, agitator, outlet valve, inlet, air vent, safety valves, volume meter, and thermometer. 

Milk Preservation 

Milk is highly perishable and it must be treated to preserve its quality. Some milk preservation methods include the following. 

• Cooling: The milk should be cooled to 5°C or lower to restrict bacterial growth. 

• Heating: Pasteurisation temperatures kill up to 99% of pathogenic microorganisms responsible for spoilage.

• Chemicals:  Preservatives such as sodium carbonate, sodium bicarbonate, formalin, formaldehyde, boric, benzoic acids, salicylic acids etc. are also used.
• Lactoperoxidase: This method is also known as cold sterilisation. Usually, milk contains the natural lactoperoxidase enzyme. Thiocyanate and hydrogen peroxides are added at 30:70 ppm levels to activate the lactoperoxidase system.

4. Milk Processing 

Here’s what a typical process in a milk plant looks like. It outlines the basic steps in the production of whole milk, semi-skimmed milk and skimmed milk, cream, butter and buttermilk. In such plants, yogurts and other cultured products may also be produced from whole milk and skimmed milk. 

Image source: Overview of Dairy Processing

5. Packaging of Milk Products

Packaging is critical for storing, protecting, transporting, marketing, and selling dairy items, acting as a link between the manufacturer and the final consumer. Some examples of packaging materials for milk products include the following. 

• • Paper/ paper-based: Cartons, boxes, bags, etc. are used because of low cost and easy disposal. However, it has low weight strength and is tear-prone. 

• Plastics: Thermoformed plastics such as bottles, cartons, etc. are used. Flexible plastic packaging such as pouches, bags, and wrappers. Types of plastic packaging include polypropylene, polystyrene, polyester, and cellophane coated with polyethylene. 

• Aluminium foil: This packaging is greaseproof, non-sorptive, shrink-proof, odourless and tasteless, hygienic, non-toxic, etc. However, it is susceptible to strong acids and alkalis and has low tear strength. 

• Glass: Glass may be transparent or opaque and is used in the form of bottles, jars, jugs, etc. Glass offers strength, rigidity, and an excellent gas and water vapour barrier but is heavy-weight and fragile. 

• Tinplate: It consists of a thin sheet of mild steel coated on both sides with a layer of tin in the form of cans. It offers good strength, and exceptional barrier properties but is costly, heavyweight, and difficult to dispose of. 

• Laminates: Some common laminates include paper polythene, cellophane-polythene, and polyester polythene. They improve barrier properties, grease-resistance, and can also heat seal. 

Final Words 

The modern dairy industry primarily consists of two segments, one is milk production on farms and the second is milk processing in the plants. Since there are multiple steps involved in upstream and downstream processes, attention to detail is required. From the farm to the table, various technologies and practices are employed to ensure that dairy products are safe, nutritious, and of high quality. The integration of automation, quality control, and cold chain logistics plays a vital role in meeting the demands of today’s consumers.

To know more about how Rinac can support your cold storage needs in the modern dairy processes, get in touch with us today.