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Introduction to Fermented Dairy Products

By PMG Engineering ·

 

Fermented dairy products have been a part of human diets since as early as 10,000 B.C. They are produced by introducing beneficial bacteria into milk, leading to a range of products with improved digestibility, unique flavors, and extended shelf life. As a food processing consultant or food manufacturing consultant, understanding the fundamentals of milk fermentation is essential for optimizing dairy product development.

What is Fermentation in Dairy?

Fermentation is a metabolic process where microorganisms such as Lactobacilli and Bifidobacteria partially digest milk sugars (lactose), converting them into lactic acid. This natural transformation:

  • Enhances the taste and texture
  • Increases shelf life
  • Improves nutrient absorption
  • Introduces probiotics for gut health

This process is widely used in food technology consulting to design safe, functional dairy products.

How Fermentation Works in Dairy Processing

  1. Microorganisms break down sugars like glucose for energy.
  2. In the absence of oxygen, they switch to anaerobic fermentation.
  3. This process yields lactic acid, which lowers pH and helps coagulate milk.
  4. The result is a sour-tasting, thicker product that resists spoilage.

Types of Fermented Dairy Products

Fermented milk, also known as cultured dairy, is made using specific lactic acid bacteria (LAB). These bacteria thrive in nutrient-rich milk environments and help preserve the product while enhancing nutritional value.

Here are some widely consumed fermented dairy products:

1. Dahi (Curd)

  • Made via bacterial fermentation of milk.
  • Uses "dahi cultures" for fermentation.
  • Fat content requirements:
  • 1.5% for double-toned milk
  • 3.0% for toned milk
  • 3.2% for cow milk

2. Shrikhand

  • A semi-solid, sweet-sour dessert popular in western India.
  • Made from curd (dahi) and has a shelf life of 40 days at 8°C.
  • Common during festive occasions.

3. Buttermilk

  • Liquid byproduct of curd churning.
  • Can be plain, salted, or spiced.
  • Shelf life: 7 days under refrigeration.

4. Cheese

  • Produced by separating curds and whey.
  • Curds are aged, pressed, and often salted.
  • Common bacteria used:
  • Lactococcus lactis
  • Streptococcus thermophilus
  • Lactobacillus strains

Industrial Production Example: Shrikhand

Shrikhand is an excellent example of food factory design and food consultancy services applied to traditional dairy:

Step-by-Step Process:

1. Milk Preparation

  • Use cream separator to get high-fat cream (70%+) and fat-free skim milk.

2. Pasteurization

  • Skim milk: 90°C for 10 mins
  • Cream: 85°C for 16 secs

3. Inoculation

  • Add 0.5% lactic starter to skim milk in a sterile vat at 30°C.

4. Incubation

  • Maintain 30°C for 8 hours until acidity reaches 0.8–1.0%.

5. Whey Separation

  • Centrifuge to obtain chakka (solids).

6. Mixing

  • Combine chakka with cream and sugar (target: 6% fat, 42% sugar).

7. Flavoring and Packaging

  • Add desired flavors.
  • Package in sterile cups and refrigerate.

This process showcases how project management in food processing plants ensures standardization, quality, and food safety.

Benefits of Fermented Dairy Products

  • Improved digestion and gut health
  • Increased bioavailability of calcium and minerals
  • Suppression of harmful bacteria
  • Better shelf stability of milk-based products

These advantages make fermented products a focus for food business consultancy and R&D in dairy technology.

Conclusion

Fermented dairy products like curd, buttermilk, shrikhand, and cheese are crucial in today’s food manufacturing and consultancy for food industry. Using food industry consultants, brands can achieve consistent quality, hygiene, and compliance with global food safety standards.

Frequently asked
What actually happens during milk fermentation, and why does it thicken the product?
In dairy fermentation, microorganisms such as Lactobacilli and Bifidobacteria partially digest lactose and convert it into lactic acid. They break down sugars like glucose for energy and, in the absence of oxygen, switch to anaerobic fermentation. The lactic acid produced lowers the pH and coagulates the milk, giving a sour-tasting, thicker product that resists spoilage while improving taste, texture and nutrient absorption.
What fat content do we need to hold for dahi made from different milk types?
For dahi (curd) produced by bacterial fermentation of milk using dahi cultures, the fat content requirements are 1.5% for double-toned milk, 3.0% for toned milk and 3.2% for cow milk. Fixing the incoming milk standardisation to the intended dahi grade is the first control point in any curd line.
Can you walk me through the industrial process steps for shrikhand?
Industrial shrikhand production runs as follows: separate milk in a cream separator to get 70%+ fat cream and fat-free skim milk; pasteurise skim milk at 90°C for 10 minutes and cream at 85°C for 16 seconds; inoculate skim milk with 0.5% lactic starter in a sterile vat at 30°C; incubate at 30°C for 8 hours until acidity reaches 0.8–1.0%; centrifuge to obtain chakka; mix chakka with cream and sugar to 6% fat and 42% sugar; then flavour, fill into sterile cups and refrigerate.
What shelf life should we plan for on shrikhand and buttermilk?
Shrikhand, the semi-solid sweet-sour dessert made from dahi and popular in western India, has a shelf life of 40 days at 8°C. Buttermilk, the liquid byproduct of curd churning and sold plain, salted or spiced, holds 7 days under refrigeration. Both figures assume the cold chain is maintained after packaging.
Which cultures are used in cheese manufacture?
Cheese is produced by separating curds from whey, after which the curds are aged, pressed and often salted. The bacteria commonly used include Lactococcus lactis, Streptococcus thermophilus and Lactobacillus strains. Selecting the culture set is a core process design decision, since it drives acidification, flavour development and the final texture of the cheese.
Beyond flavour, what benefits do fermented dairy products give the consumer?
Fermented dairy products such as curd, buttermilk, shrikhand and cheese improve digestion and gut health, increase the bioavailability of calcium and minerals, suppress harmful bacteria, and give better shelf stability to milk-based products. Fermentation also introduces probiotics and improves digestibility, which is why these products are a focus area for dairy technology R&D and product development.
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PMG Engineering. (2021). Introduction to Fermented Dairy Products. PMG Engineering. https://pmg.engineering/Article/91/introduction-to-fermented-dairy-products/

https://pmg.engineering/Article/91/introduction-to-fermented-dairy-products/