Curd Processing- An Insight

Most common as well as traditional dairy based product, Curd, locally known as Dahi, is consumed widely all over the world. Curd falls under the category of fermented dairy product, produced from heat treated milk after inoculation with certain Lactic Acid Bacteria (LAB) in the form of starter culture. Lactic acid bacteria multiply, grow and produce lactic acid, acetic acid, and carbon dioxide by utilizing available lactose in milk. Some bacteria use citric acid of milk to produce certain volatile organic compounds mainly diacetyl, which is mainly responsible for flavor of Dahi.

Due to its rich nutritional profile and high consumer demand, it is commercially produced to meet the market demands. A new revolution in the industrial manufacturing of Dahi is using Dahi as functional food.

Principle behind Curd Production

Curd has live cultures and the lactose in the milk is converted to lactic acid by the action of starter cultures and the lactic acid act as preservative for the milk and the low pH (4.5- 5.0) also inhibit the growth of harmful micro-organism, thus increasing the shelf life of the product. Dahi is manufactured using single or mixed cultures, Lactococcus cremorisLactococcus diacetylactis, along with Leuconostoc species, Lactococcus lactis, a combination of acid and flavor producing bacteria. These bacteria are responsible for imparting firm body, sweetness, and a mild acidic flavor to the Dahi increasing its acceptability to the consumer.


Process Flow chart of Curd:


Curd Processing Steps

  1. Reception of milk: Fresh, good quality milk is received and analyzed for SNF and fat%.
  2. Pre-heating: Done at 30-40°C
  3. Standardization: 5% to 3.0% fat and 10% solids not fat.
  4. Preheating (Optional): It is an optional step to heat milk up to 60°C
  5. Homogenization: Milk is subjected to high pressure pump forcing milk through extremely small orifice for even distribution of fat globules. Homogenization reduces the cream layer formation during incubation and single-stage Homogenizer, or double stage homogenizer can be used as per process requirement. After homogenization all the fat globules of the milk has an average size below 1 micron.
  6. Pasteurization: Milk is heated to 85-90°C for 15-30 minutes and temperature bought down to 3-4°C.
  7. Pre-heating: Pasteurized milk is preheated to 40-45°C and transferred to inoculation tank.
  8. Inoculation: Milk is inoculated with 1-2% of specific curd starter culture at 37°C. The incubation tanks are insulated, to ensure that the temperature remains constant during the incubation period. The tanks can be fitted with pH meters to check the development of acidity (4.2 – 4.5)
  9. Packaging: The inoculated milk is then packaged in separate cups with lids. Dahi is generally packaged in polyethylene, polypropylene, polystyrene packaging material and plastic cups
  10. Incubation: Cups are arranged in crates which are then transferred to hot room (37˚C) while the fermentation process proceeds. In case of set curd, incubation is done when the product is in its final retail container at 30-42°C for around 4-5 hours, while for stirred types of products it can be done within the inoculum/incubation tank and then packed in pouches.
  11. Cooling: The pH of the milk in the cups should be regularly checked and when it reaches 4.4-4.5, these crates are transferred to room with temperature 3-4oC for proper setting
  12. Storage: It is stored in the cold store below 6°C

Difference between Industrial curd and Homemade curd

Dahi produced on domestic levels has undefined cultures, thus, difference in texture and taste is often observed. While in commercial manufacturing, process set points are defined and followed to get consistent product.

Difference between Yoghurt and Curd

Quite common confusion is that yogurt and curd are same. But that is not the case.


Processing of Squashes

Among the various activities, which are termed agriculturally based, fruits and vegetable processing are the most important. Over recent years, consumers have shown an increasing interest in health and wellbeing, with many wanting food and drink products that are healthy and nutritious yet fit in with busy lifestyles. Fruit Squashes is one beverage that has seen a dramatic increase in consumer demand, especially in summers. So let’s find out what is it and how is it processed.

Definition of Squash:

Squash is a non-alcoholic concentrated syrup that is usually fruit-flavored and usually made from fruit juice, water, sugar, or a sugar substitute. Some traditional squashes may contain herbal extracts, most notably elderflower and ginger. Squash must be mixed with a certain amount of water before drinking. Citrus fruits (particularly orange, lime and lemon) or a blend of fruits and berries are commonly used as the base of Squash

As per FSSAI specifications, the Squash should contain no less than 25 per cent fruit content in the finished product, and the total soluble solids content should not be less than 40° Brix. The acidity of the Squash should not be more than 3.5 per cent as anhydrous citric acid. The maximum permissible limit of preservative in Squash is 350ppm of sulphur dioxide or 600 ppm of benzoic acid. Potassium metabisulphite is not added in dark coloured fruits as it may bleach the anthocyanin pigments. In such beverages, sodium benzoate is used.



  1. Selection of fruit: Ripe fruits are selected. Overripe and unripe fruits adversely affect the quality of the juice.
  2. Washing: Dirt and spray residues of arsenic, lead etc., are removed by washing with water or using dilute hydrochloric (HCl) acid solution (0.5%) followed by washing in water.

  1. Sorting and grading: Send the fruits to the grading and sorting table/machine to manually check the uniformity of ripened fruits.

  1. Peeling/deseeding/destoning: As per the fruits selected, it is sent for peeling, de-seeding and de-stoning process (removal of seeds).

  1. Cutting/slicing/crushing: Conduct the slicing operation of the peeled fruit using a slicer and send it to the crusher. Depending on the type of fruit used an appropriate machine/ press to extract the juice. E.g. citrus fruits, which are naturally juicy, use a mechanical presser to extract the juice. In the case of fruits such as mango, guava, pineapple, strawberry to extract the juice, first pulp is extracted by pushing through a perforated metal plate


  1. Pasteurization: Once the juice is extracted, it is sent for pasteurization at 80-95°C for 10-12 mins. Three types of pasteurizer are generally used for juices plate pasteurizer, tubular pasteurizer and steam pasteurizer, and plate pasteurizer is the most prevalent.

Plate Heat  Exchanger working:

These plates are commonly made of steel, aluminum alloy, titanium, nickel, or even graphite materials and are the thermally conductive pathways between the two working fluids. Their corrugations increase surface area and create turbulence, both of which help enhance the heat transfer rate through the exchanger. One fluid (red) enters its inlet through the top right and successively flows down every even-numbered plate, while the other fluid (blue) enters through the bottom left and is pumped up every odd-numbered plate. This ordering allows for operators to easily add/remove plates to the stack, effectively increasing or decreasing the heat exchanger’s heat transfer capacity at any time.

  1. Clarification: Rapid methods such as centrifugation(with a speed of 6000 to 6500 RPM. and filtration can produce a clear juice. A continuous or a decanting centrifuge with automatic desludging to produce a clear or nearly clear juice is quite effective. Ultra-clarifier can also be used.

  1. Syrup preparation: Simultaneously, sugar, water and acid is mixed and heated to dissolve to form a syrup.
  2. Mixing: Syrup and clarified juice are mixed in a tank.
  3. Addition of preservative: Sodium benzoate or KMS is generally used.1.0gm/lit is used in case of Sodium benzoate.
  4. Cooling: The product is cooled to room temperature.
  5. Deaeration: Freshly extracted juice contains appreciable quantity of oxygen which may affect the quality of juice if not removed before packing.
  6. Bottling and capping. Aseptic processing and packaging is done which are defined as- when a commercially sterile product is packed into a pre-sterilized container in a sterile environment.

Process flow chart of Squash:

Following is the process flow chart of fruit squash.


Squash is a diluted fruit juice. Among all beverages, Squash is quite popular all over the world. It consists of strained juice containing moderate fruit pulp quantities (optional) to which sugar is added for sweetening. Acid is added to lower the pH, which arrests microorganisms responsible for spoilage of the product. The acid, in combination with sugar, also improves the taste of sugar. Sulphur dioxide (SO2) is also used as a preservative to prevent non-enzymatic browning reaction.


GMP Inspection Audit – Make Good Quality Your Mission

Good Manufacturing Practices (GMP) is a system that ensures that the goods produced by various manufacturing facilities are consistently produced and controlled according to specified quality standards. There are GMP systems for everything from cosmetics to pharmaceutical products and of course, food.

GMP looks at every aspect of the manufacturing process to guard against potential risks that can prove detrimental to its products. Cross-contamination, mislabeling, and adulteration are just a few of the things GMP aims to prevent. Thus it aims to make customers happy and satisfied by delivering them safe food.

Good Manufacturing Practices:

It includes the following areas:

1.1. Personal Practices and Hygiene- This includes personnel arriving in the manufacturing unit with clean hairs, hand, nails, body, no perfume or aftershave. They should wash and sanitize their hands each time they enter the production area, after visiting the toilets, after eating or drinking, after handling RM and cleaning. They should also remove their neck chains, rings, earrings, wrist chains, watches and piercing, Leave personal items in their locker, and change into company-provided clothing.

1.2. Storage and Handling: Products that are produced should be stored and handled under clean and sanitary conditions. For e.g.

  • All items should be stored to avoid direct contact with the floor or walking surfaces
  • Product or ingredient containers must not be stored immediately adjacent to containers with waste or non-product item.

1.3. Equipment Maintenance: Procedures describing preventive maintenance and calibration of all the equipment and instruments that can affect food safety (eg: thermometers, thermocouples, metal detectors, scales, pH meters)

 1.4. Equipment and Utensils: These should be clean-able and adequately installed and maintained. Food contact surfaces should resist corrosion and be made of non-toxic materials. Freezers and cold storage units must have a temperature monitoring device to clearly show the compartment’s inside temperature where food is stored.

1.5. Pest Control: Should be done to prevent transmission of diseases and pathogens. For this, one should use traps and baits stations in strategic areas, or by using proofing doors, windows etc. EFK (electronic fly killer) and insect light trap should be placed at a standard height (at 6 feet) and the lights used in this should be replaced/checked one time per months; pheromone traps are also used for cockroaches, these should be well placed & operating,

1.6. Housekeeping: Effective housekeeping can help control or eliminate workplace hazards. Poor housekeeping practices frequently contribute to incidents. The 5S theory can best explain this.

1.7. Quality Control: It is a part of GMP which is concerned with sampling, specification, testing and also organization, documentation.

Documenting GMP

To assist in the effective implementation of Good manufacturing practices (GMP) within the food business, it is advisable to document how the food business will implement relevant Good manufacturing practices (GMP). It is equally important to maintain records to support any Good manufacturing practices (GMP).


The GMP Inspection

To ensure the effective implementation of Good manufacturing practices (GMP), it is beneficial for the food business to undertake its own internal GMP inspection. This generally involves reviewing the site visually to see if it complies with customer expectations and regulatory requirements. This inspection should not merely be a “tick and flick” activity but a comprehensive assessment of the site to determine the level of GMP compliance. A record of any GMP inspection undertaken is required to be kept as evidence in a third-party certification audit. Any issues identified during the GMP inspection should be quickly rectified, and a root cause analysis should be performed to avoid reoccurrence.

Why are GMP food safety audits done?

A GMP Food Safety Audit focuses on preventing contamination and reducing risk. GMP audits are done to verify the company’s food safety practices; it informs that the processes are effectively implemented, including their HACCP Program. Thus, a  GMP audit can help companies improve their food safety and quality systems. It is a stepping stone to prepare your company for accredited certification to SQF, FSSC 22000, BRC. Different companies follow the different format of an audit checklist.  Following is an example of an audit checklist.


One of the most critical components of GMP is quality control (QC)—the process of sampling, testing and comparing results with pre-agreed specifications as part of the overall quality assurance (QA) process. GMP helps to ensure the consistent quality and safety of products by focusing on five key elements, which are often referred to as the 5 P’s of GMP—people, premises, processes, products and procedures (or paperwork/documentation). Moreover, if all five are done well, there is a sixth P -profit!

Businesses in the food industry have a legal and moral responsibility to prepare food that is safe for the consumer and by not implementing adequate good manufacturing practices (GMP), a food business can risk its self reputation and will also risk its consumers.

Tetra packs- Are they smart solution for packaging

A tetra pack comes under the category of aseptic packages. For a material to be aseptic, it should have the following features-

  1. The packaging material must be compatible with the product intended to be packed.
  2. The physical integrity of the package is necessary to assume containment of the product and maintenance of sterility.
  3. The packaging material must be able to withstand sterilization and be compatible with the methods of sterilization.
  4. The package must protect the product from oxygen; also, the package must retain the product’s aroma.

What is Tetra pack?

Tetra pack is the most common name for aseptic cartons used for liquid food items which have to be stored for up to one year without refrigeration. Aseptic here means “free from pathogenic micro-organisms, ” so this packaging process eliminates the food and packages from harmful elements. This type of packaging also blocks light completely to preserve vitamins A, B2, B6, B12, C and K, which are all photosensitive and would become damaged in the presence of light. 

Structure of a Tetra pack:

A tetra pack is made of six layers i.e.

  1. Polyethylene – Contributes 15% of the total packaging; it protects from outside moisture.
  2. Paper – Contributes 80% of the total packaging for providing stability, strength and smoothness to the printing surface.
  3. Polyethylene – Polyethylene acts as an adhesive layer between other layers.
  4. Aluminum foil – Contributes 5% of the total packaging. It forms a barrier against light and oxygen, eliminating the need for refrigeration and preventing spoilage without using preservatives.
  5. Polyethylene – Acts as an adhesion layer.
  6. Polyethylene – Seals the Liquid from inside.

  Diagrammatic Representation of Tetra pack acting as a Barrier.

Types Of Tetra packs:

These packages come in various sizes and shape configurations. These packages also have a variety of openings and closures appropriate to product and consumer needs. Depending on the two points mentioned, following diagrams shows the types of tetra packs available.

Myths related to tetra packaging:

  1. Tetra packaged milk needs boiling

No, boiling of tetra pack milk is an unnecessary step. Tetra packaging involves UHT treatment of milk into pre-sterilized packages in a sterile environment, thus there is no risk of contamination and therefore no need to boil the milk before use.

  1. Tetra packages are Sustainable

Tetra packs are recycled, but the recycled part is not used for manufacturing of tetra packs, hence they are said as non-sustainable. It is unclear whether this is because their paperboard needs to come from virgin sources to avoid contamination, or whether the quality of the recycled paperboard isn’t high enough to make new cartons, or there is some other reason. Whatever the reason, it is turned into office paper.


The Tetra pack carton is the future packaging – being primarily made using paperboard (a renewable forest-based resource) and fully recyclable. Not only this it offers consumers convenience, easy opening, optimal shelf life.

Product Recall and its Types

Product recalls are inevitable reality of working in food industry which can be frightening for both food processers as well as for consumers due to the harm and fear they cause among them. People generally focus on its negative side only, but they are very essential and must happen regularly as they can prevent serious damages to the consumer’s health. Recently, a very well-known potato chips brand had to voluntarily pulled out its product from western market due to presence of undeclared milk allergen in it. Due to huge spike in the number of cases of food product recalls presents devasting effect on the image of food industry. But the good news is that there are measures available for food industries, which can apply for reducing/preventing its number.

  1. Definition

Food recall is essential component of national food control system that is used for the management of risks in response to food safety events and emergencies. Product Recall is action of removing food products from the market at any stage of the food chain which may pose a safety risk to consumers. A food recall may be initiated because of a report or complaint from a variety of sources − manufacturers, wholesalers, retailers, government agencies and consumers. It may also occur as a result of a food business’s internal testing and/or auditing. Recalls are conducted by food businesses for protecting their consumers from any kind of severe health consequences like injury, illness or even death.

  1. Reasons of Product Recall

Food recalls may happen for many reasons, including but not limited to:

  1. Discovery of pathogenic organisms, including bacteria such as Salmonella or parasites such as Cyclospora.
  2. Discovery of objectionable foreign objects such as broken piece of glass, metal, or plastic.
  3. Discovery of a major allergen that does not appear on the product label.
  4. Discovery of a harmful chemical compound which is either not allowed to be used in food products or is present in the concentration higher than its acceptable limits. Example: MSG, pesticide residues, antibiotics etc.


  1. Types of Recall

3.1. Trade Level Recall

A trade recall is conducted when the food has not been sold directly to consumers. It involves recovery of the product from distribution centers and wholesalers. It may also involve recovery of product from hospitals, restaurants, and other catering establishments.

3.2. Consumer Level Recall

A consumer recall is the most extensive type of recall. It involves recovery of the food product from all points in the production and distribution chain including recovery of product in the possession of consumers.

  1. Food withdrawal Vs Product Recall

Many professionals often use the term food withdrawal and product recall interchangeably, but there is a huge difference between them. Withdrawal of food product from the market is the action of removing food from the supply chain where there is no public health and safety issue associated with it. A withdrawal may occur in two circumstances:

  • when the food product has a quality defect (e.g., color or texture), is underweight or has labelling irregularities that do not pose a potential risk to public health and safety.
  • as a precaution, pending further investigation of a potential public health and safety risk. However, if a risk to public health and safety is established, the food must be recalled.
  1. Risk Associated with Product Recall

5.1. Increase in Direct Costs for Company:

The direct costs of the actual recall generally include:

  • Notifying retailers and regulatory bodies
  • Pulling products, also known as reverse logistics
  • Storing and disposing of contaminated or mislabeled products
  • Any additional labor needed to carry out these tasks and investigate the source of the problem.

5.2. Lost Sales:

Any recalled products a manufacturer has to pull from shelves represent lost revenue opportunities. Retailers might shut off entire SKUs if manufacturers are not yet sure which batches are impacted, which could mean extra and unnecessary lost sales opportunities. And if the manufacturer shuts down production, regardless of whether it’s voluntarily or by mandate, the shutdown leads to still more missed revenue opportunities.

5.3. Damage to Brand Name:

Product Recall can damage a brand or company’s reputation and level of trust in the eyes of consumers. If a manufacturer is fully transparent and proactive about handling the recall, that can minimize the damage.

At first instance food recalls are seen as public health issue, but they are also responsible for significant economic issues also. According to findings of one reputed survey, the average cost of a recall to a food company is around $10M for direct costs, in addition to brand damage and lost sales. However, the costs for larger brands may be significantly higher based on the preliminary recall costs reported by firms of some recent recalls. Thus, it can be one of the biggest threat to profitability if not managed properly.

Processing of Unsweetened Condensed Milk

Evaporated milk, also known as unsweetened condensed milk or dehydrated milk, is a form of concentrated milk with a larger shelf life than regular milk.

Unsweetened condensed milk has about 60% of the water removed from it. After the water is removed, the liquid that remains is cooled, sterilized at high heat (around 240° F), and then canned. The heating process gives evaporated milk a darker color and a slightly sweeter, caramel-like taste. Evaporated milk also has a higher concentration of nutrients and energy. This means that one cup of evaporated milk will have more nutrients and provide more energy than one cup of fresh milk. Vitamin D is also usually added to boost the nutritional value of evaporated milk.

The unsweetened condensed milk can be made from whole milk, skim milk or recombined milk with the skim milk powder, anhydrous milk fat (AMF) and water.


Following steps are followed to manufacture Unsweetened Condensed Milk.

  1. Reception of milk and testing: The raw milk is transported from the dairy farm to the plant in refrigerated tank trucks. The milk is tested for odor, taste, bacteria, sediment, and the composition of milk protein and milk fat at the plant. 
  1. Standardization: In this fat and solids not fat (SNF) has been adjusted to a predetermined level. The composition of evaporated low-fat milk is 7.5%–9.0% fat and 18%–22% non-fat milk solids.
  1. Preheating/Pasteurization: To improve the concentrated product’s heat stability and impart optimum viscosity to the finished product, the fluid milk is preheated before it is condensed.

  1. Evaporator: Water is evaporated, employing indirect heating. Product and heating medium (steam) are kept separate from one another utilizing a special steel sheet, to minimize the thermal impact on the products from the heat applied, evaporation takes place in a vacuum at pressures of 160 – 320 hPa, equivalent to water boiling temperatures of 55°C – 70 °C. In milk Industry, generally, three types of evaporators are used- Falling film evaporators, Rising Film Evaporators, Circulation / vertical Evaporators, Horizontal Tubes Evaporator, explained below.

  • Multiple-effect Evaporator: A multiple-effect evaporator, is an apparatus for efficiently using the heat from steam to evaporate water. In a multiple-effect evaporator, water is boiled in a sequence of vessels. If two evaporators are connected in series, the second effect can operate at a higher vacuum (and therefore at a lower temperature) than the first. Thus the vapour evolved from the product in the first effect can be used as the heating medium for the next effect, which operates at a lower boiling temperature due to the higher vacuum.

  • Falling film evaporators: A falling film evaporator (FFE) is a specific type of vertically oriented shell and tube (S&T) heat exchanger used to separate two or more substances with different boiling point temperatures. The liquid to be concentrated is supplied to the top of the heating tubes and distributed in such a way as to flow down the inside of the tube walls as a thin film. The liquid film starts to boil due to the external heating of the heating tubes and is partially evaporated as a result. The downward flow, caused initially by gravity, is enhanced by the parallel, downward flow of the vapor formed. Residual film liquid and vapor is separated in the lower part of the calandria and in the downstream centrifugal droplet separator.


Difference between Rising Film Evaporator

  1. Homogenization: Homogenization is a mechanical treatment of the fat globules in milk brought about by-passing milk under high pressure through a tiny orifice, which results in a decrease in the average diameter and an increase in number and surface area, of the fat globules. It is done to create a stable emulsion where the fat globules do not rise to form a cream layer.


  1. Cooling: After homogenization, the pre-treated milk is cooled to about 14 °C to send for further processing.
  2. Canning: Canning machines for condensed milk automatically fill and seal the cans before sterilization.
  3. Sterilization: Done in two ways i.e.

  (a) Continuous Autoclave – In the continuous autoclave, the cans pass through on a conveyor belt at a precisely controlled speed.

   (b) Batch Autoclave – In this the cans are first stacked in special crates, which are then stacked inside the autoclave.

  1. Storage: Once it is autoclaved, it is cooled to about 5°C and stored.

The process, as mentioned above was for retort processed unsweetened condensed milk. If the milk is to be condensed by UHT Processing, the above whole process remains same except point 7 and 8, which will be replaced by point 11 and 10 described below.

  1. UHT Treatment: The milk is pumped to the UHT plant/heat exchanger, where it is heated to 122°C –140 °C for a period ranging from 4 seconds to 2 minutes. Generally, a plate heat exchanger is preferred, and if UHT Treatment is used in the processing, than the preheating phase done in this case will below.
  2. Aseptic Filling: Aseptic processing and packaging is the filling of commercially-sterilized products into pre-sterilized containers.

Flow chart of Unsweetened Condensed milk:



When you see condensed milk can say that it is sweetened or not, be assured that it is sweetened. The most pronounced difference between condensed and evaporated milk is the absence of sugar or sweetener in the latter. Condensed milk will almost always be sweetened. Once the water is gotten rid of, the manufacturers use sugar to sweeten it. In case of unsweetened condensed milk, there is no addition of sugar in evaporated milk, and thus it is not sweeter to taste.

Introduction to Ghee Processing

India is the world’s largest producer and consumer of milk and dairy products. Ghee currently controls the second largest market share in terms of revenue in the Indian market. With the growth of the organized sector of the dairy industry and establishment of modern dairy plants, the emphasis has shifted to conducting investigations on newer and larger-scale methods of ghee manufacture which could profitably be adopted for routine ghee production by these dairies instead of the desi method used in the dairy.

There are five methods of Ghee Processing:

  1. Desi method:

It is an age-old process adopted mainly in rural areas/villages and at urban household       levels because of simplicity in equipment and technique. This traditional method of making ghee contributes about 80% of the total ghee produced in the country. This method usually involves two routes-

  1. Lactic acid fermentation of raw or heated milk is followed by the churning of curd into Makkhan (butter) .


 2. Separation of malai (clotted cream) from the boiled milk and its churning into butter  which is further heated to make ghee.



  1. Direct Creamery method:

The direct cream method is a commercial ghee manufacturing process. Here a kettle is used to boil the milk cream. These kettles are mostly made of steel, and they come with a steam-heated jacket and fixed with an agitator, a steam regulator valve, pressure, and temperature gauging devices and a portable, hollow, stainless steel tube with central boring for draining out the contents.

Heating gets stopped when brownish froth is seen on the surface, and the color of the ghee residue becomes golden yellow or light brown. The small dairies use a technologically improved method for ghee making which involves the separation of cream from milk by centrifugation.



  1. Creamery-Butter Method

In this method, unsalted creamery butter or white butter or cooking butter is used as a raw material for ghee making. First, the butter mass is melted at 60° C. The molten butter is pumped into the ghee boiler. The steam pressure is increased slowly to

raise the temperature of butter to 90° C. This temperature remains constant as long as the moisture is being driven off. The scum, which collects on the top surface of the product is removed from time to time. The temperature gradually rises, and the heating at the last stage is carefully controlled. The disappearance of effervescence, the appearance of finer air bubbles on the surface of fat and browning of the curd particles shows the end-point. At this stage, the typical ghee aroma is also produced. The final temperature of clarification is adjusted less than 115° C. The ghee is then pumped, via oil filter or clarifier, into another tank, cooled by re-circulating water at 60° C. The ghee is then packed in suitable containers.

  1. Pre-stratification Method:

Butter is produced from aged cream of 38 to 40% fat using continuous butter making machine or batch churn. Butter is then transferred to butter Melter, and melt at 80°C. This molten butter is kept undisturbed in a ghee kettle or boiler at a temperature of 80-85°C for 30 min. Here, in ghee kettle, stratification of mass takes place, product stratifies into three distinct layers. Denatured protein particles (curd particles) and impurities are collected on the top layer and floats. The middle layer consists of clear fat and bottom layer consists of buttermilk serum carrying 80% of moisture and 70% of solids-not-fat contained in butter.


  1. Cream de-emulsification method:

This method of continuous ghee making is based on the principle of de-emulsification of fat in cream from oil-in-water phase to water-in-oil phase. In this process, milk is separated into the cream of 40% fat using a centrifugal cream separator a clarifixator. This cream is further concentrated in a concentrator which work under centrifugal force. The de-emulsification of fat is done mechanically in the clarifixator and concentrator. Scraped surface heat exchanger is used to generate flavor and remove most of the moisture from fat concentrate. The traces of moisture left in ghee are removed in a vapor separator and the ghee residue removed by an oil clarifier.

 Hazards in Ghee Processing:

  1. Physical Hazards
  • An extraneous matter like Foreign Particle, dust, dirt, glass, stone etc. due to low storage, environment.
  • Very fine particles in ghee due to improper settling.
  1. Chemical Hazard
  • Probable Cross-contamination may occur from remaining cleaning agent. residues due to unclean pipelines.
  • Polymer Migration from packaging Material.
  • Cross-contamination due to residue of cleaning chemicals. 
  1. Biological Hazard
  • Coliforms, Clostridium Botulinum, Salmonella, E.coli, Yeats & Mold / Aerobic spores due to improper cleaning.


Ghee is an essential part of Indian diet, religious, ceremonial function, and therapeutic purposes. Ghee is broadly prepared by two methods: traditional method and industrial method viz. creamery-butter method, direct cream method, pre-stratification method, and continuous method. On the word of market dynamics, more than 90% of the ghee is produced by traditional method by unorganized sectors in India by making makkhan and then converting it into ghee.

Introduction to Processing of Margarine

Margarine is an emulsified, fatty food product initially created as a substitute for butter. While originally made from animal fat in the 1800s, today the primary ingredients include vegetable oil, water, salt, emulsifiers, and milk. Technically, It is a water-in-oil (W/O) emulsion in which the water phase is finely dispersed as droplets in the continuous fat phase.

Difference between Butter and Margarine:


Manufacturing of Margarine requires high processing. Following are the processing steps-

  1. Preparation of Ingredients: When the ingredients arrive at the margarine manufacturing facility, they must first undergo a series of preparatory measures. Like safflower, corn, or soybean, the oil used, like safflower, is treated with a caustic soda solution to remove unnecessary components known as free fatty acids. Next, the oil is sometimes bleached with a mixture of bleaching earth and charcoal in another vacuum chamber. The bleaching earth and charcoal absorb any unwanted colorants and are then filtered out from the oil. Whatever liquid is used in the manufacturing process—milk, water, or a soy-based substance—it too must undergo preparatory measures like milk will undergo pasteurization to remove the microbial load.
  1. Hydrogenation: The oil is then hydrogenated to ensure the correct consistency for margarine production. In this process, hydrogen gas and a metal catalyst are added to the oil under pressurized conditions. All this heavy processing will lead to the production of trans fats.

  1. Melting of oils: Oils are transferred to a tank (say tank 1) to obtain a homogenous melt ensured by continuous stirring at 60°C-70°C.
  1. Preparing the aqueous phase: The aqueous phase is generally milk, water, salt and other water-soluble ingredients are dissolved and mixed in tank 2 to make up the final vol. which constitutes 16% of the final wt. of Margarine.
  2. Mixing: Contents of both the tank 1 and tank 2 are sent to the emulsifying tank (say tank 3) where they are mixed.

  1. Adding Emulsifier and other fat-soluble ingredients: Emulsifier such as lecithin, mono or diglycerides are generally used. Lecithin should be first dissolved in a small vol. of oil and fat blend preferably in a ratio 1:4 at 65°C-70°C. The mix is than poured in the main tank i.e., tank 3 and mixed. Apart from this antioxidant, color, flavor are also added at this point. At this phase, we get a semi-liquid kind of consistency.
  1. Pre-crystallization: The contents are then transferred to the pre-crystallizer where the scrapper speed of 300-1000 rpm and a temp. of 10°-22°C is maintained.

The pre-crystallized fat is then passed through a pin worker. The rotating pin helps the pre-crystallized fat to get adequately homogenized crystallized  fat.

  1. Packing: Margarine is filled in containers and packed.
  1. Tempering: done at 5°C-7°C to stabilize the texture of Margarine.

Is margarine vegan?

The answer is yes if you are eating it in India. According to FSSAI, This is an emulsion of edible oils and fats with water which is not rancid and does not contain any mineral oil or animal body fats. Table salt content must not exceed 2.5 per cent, and the content of skimmed milk powder must not exceed 2 per cent.

Whereas in other countries FDA permits the use of animal fat the limit is only on the percentage of fat used i.e. it should not be less than 80%, it has nothing to do with the source of fat.

Butter vs Margarine: Which Is the Healthier Option?

In the general case, Margarine is not considered healthy as it contains a lot of trans fats. It is important to limit the intake of saturated fats and to avoid trans-fats altogether. It should be noted that Margarine containing trans-fats lower the levels of high-density lipoprotein (HDL) or good cholesterol and raise the levels of low-density lipoprotein (LDL) or bad cholesterol, thereby increasing the risk for coronary heart disease.


Margarine is a substitute for butter. It is not a dairy product. So, it does not contain any animal fat. It is made from vegetable oil, water, salt, and other additives. Since there is no animal fat, Margarine is low in saturated fatty acids. On the other hand, it contains monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), which are healthy fats. This is a only plus-point for Margarine over butter.

However, the flip-side of Margarine is that it contains incredibly harmful trans-fats. However, nowadays, companies are slowly lowering the trans-fat content in Margarine, and some varieties do not contain any trans-fats at all.

Plant-Based Milk

Plant-based milk,  line the shelves in the refrigerator section of most supermarkets these days. These are the milk alternatives that results from breakdown (size reduction) of plant material (cereals, pseudo-cereals, legumes oilseeds, nuts) extracted in water and further homogenization of such fluids, results in particle size distribution in range of 5–20 μm which imitates cow’s milk in appearance and consistency. Although, there is no stated definition and classification of these plant-based milk alternatives in literature, a general classification of the plant based/vegetable milk alternatives into five categories is attempted, which is as follows:

  1. Cereal based : Oat milk, Rice milk, Corn milk, Spelt milk.
  2. Legume based : Soy milk, Peanut milk, Lupin milk, Cowpea milk.
  3. Nut based: Almond milk, Coconut milk, Hazelnut milk, Pistachio milk, Walnut milk.
  4. Seed based: Sesame milk, Flax milk, Hemp milk, Sunflower milk.
  5. Pseudo-cereal based : Quinoa milk, Teff milk, Amaranth milk.

Why go for a Non-Dairy Milk?

  1. Lactose intolerance
  2. Milk allergy
  3. Don’t like milk, but like the creamy taste or need a milk-like product for cooking
  4. lifestyle
  5. Concerns about inflammation
  6. Ethical concerns















Are plant-based milk healthier than dairy (cow’s or buffalo) milk? Should people make the switch?

If you drink dairy milk and have no issues with it, there is no reason to switch to a plant-based option. Cow’s milk is a good dietary source of necessary vitamins and minerals. A serving of cow’s milk contains calcium, vitamin D, vitamin A, and is a host of micronutrients that you need in your diet and incase  you have a milk allergy or lactose intolerance you can do so  just remember to check the label before buying as most of them are fortified with different vitamins and minerals as they don’t posses it naturally. So choose a per your needs and taste.

On what basis you should switch your milk?

The quality of plant-based kinds of milk varies greatly when it comes to nutrients. Some contain virtually the same amount of vitamins and minerals as cow’s milk; others may fall far short. For example, many almond milks are much lower in protein than cow’s milk. So identify your requirements and aim for the milk that ideally contains good amounts of protein, vitamin D, iron, and calcium and have has at least 8 or 9 grams of protein per serving.

Different types of Plant-Based Milk

  1. Almond milk :

Almond tastes almost similar to regular milk but is thinner in consistency. It contains lower amounts of carbohydrates and saturated fat as compared to dairy and is also lactose-free. Unfortunately, the protein value of almond is also lower than cow milk. Almonds are rich in vitamin E, an antioxidant good for your brain, blood, and skin.


  1. Coconut Milk :

Coconut is a nutrient-dense product and is a good source of fiber. It is rich in vitamin and minerals such as iron, calcium, potassium, magnesium and zinc. It also contains a significant amount of vitamin C and E. The use of coconut milk is associated with health benefits such as anti-carcinogenic, anti-microbial, anti-bacterial, and anti-viral. It contains a saturated fat, lauric acid which is present in mother’s milk and has been related to promote brain development. Coconut milk consumption is rarely associated with allergenic reactions. Other benefits of coconut milk includes: aids in digestion, nourishes the skin and has cooling properties.


  1. Soy Milk :

Soy milk was the first plant-based milk that provided nutrients to the population where the milk supply was inadequate or for the populations who were allergic to milk proteins and were lactose intolerant. Soy milk is a good source of essential monounsaturated and polyunsaturated fatty acids considered good for cardiovascular health. It serves as an inexpensive, refreshing and nutritional beverage to the consumers. The only disadvantage of soy milk consumption is prevalence of soy allergies, making it unsuitable for population who are allergic to soy proteins. When people compare soy milk with almond, hemp, and oat milk, this milk alternative has the highest amount of protein per serving.

  1. Oat Milk :

As the name suggests, it is made from oats. Extracted from whole groats or steel-cut oats, the milk is obtained by these oats being soaked in water, blended, and finally strained using a cheese cloth. The result is a milk creamy in texture, gluten- and lactose-free, vegan, and minimal flavoring.

Oat milk is slightly sweet, with a thin consistency that is similar to low-fat milk. Oats are a good source of quality protein with right amino acid balance. Health benefits of oats are associated with dietary fibers such as β-glucan, functional protein, lipid and starch components and the phytochemicals present in the oat grains makes it the promising raw materials for the preparation of functional plant-based milk. Not only this it is naturally high on vitamins and minerals, such as vitamin A and D, iron, and calcium; and is cholesterol-free, and low in fat content. However, one catch would be that since it is made from carbohydrates, oat milk has higher sugar content, tagging it as a ‘proceed with caution’ for anyone with varying sugar levels.

  1. Quinoa Milk :

Quinoa offers more protein and fiber than most other grains, is naturally gluten-free, and contains all the essential amino acids. It is also rich in iron, magnesium, and zinc. Milk made from quinoa has a distinct flavor and is a bit nutty.

Functional components of plant-based milk.



Nutritional Comparison of Different Milks :

Conclusion :

Cow’s/buffalo milk is considered a staple in many people’s diets, but lactose intolerance, dietary restrictions, and ethical preferences have led people to discover the beauty in non-dairy options too. So if you are looking for a milk alternative as a source of nutrition, find one that has a similar protein and carbohydrate count to cow’s milk — that’s 8g and 12g respectively. Most non-dairy milk is also fortified with vitamins and minerals naturally found in animal products, making them a good source for vegans who lack these essential supplements in their daily diet.

Plant-based milk is often thinner and lighter in texture. Additives such as salt, carrageenan and vegetable gums are usually added to achieve a thicker and smoother texture while giving the milk longer shelf life. While not detrimental to your health, these thickening agents have been known to cause inflammation and gastrointestinal issues for some, which negates the benefits of adopting this dairy-free lifestyle.

Modified Atmospheric Packaging

 Isn’t it  interesting  to know that Injecting a gas increases the product’s shelf life and offers extra protection, which prevents the product from discoloration. Usually, a mixture of nitrogen (N2) and carbon dioxide (CO2) is used. Dioxygen (O2) can also be added to this combination. The use of argon (Ar) has been increasing, as this contains the same properties as nitrogen (N2).

Concept of Modified Atmosphere Packaging(MAP)

It is the practice of modifying the composition of the food packages’ internal atmosphere to improve the shelf life of a product. It is a kind of replacement of air in a pack with a single gas or mixture of gases; where each component’s proportion is fixed when the mixture is introduced. No further control is exerted over the initial composition. The gas composition is likely to change with time due to the diffusion of gases into and out of the product.

Need for MAP

Oxygen produces lipid oxidation reactions. It also causes high respiration rates in fruit and vegetables, leading to shortened shelf life. The presence of oxygen encourages the growth of aerobic spoilage microorganism and the potential formation of other unwanted microorganisms may also occur.

 By reducing oxygen and replacing it with other gases, we can reduce or delay unwanted reactions. So, to change a package’s atmosphere, the oxygen contained within must be reduced or removed.

Thus, the MAP process lowers the volume of oxygen contained within the empty space of the packaging containing the product or  Oxygen is often replaced with other gases.

Gases used in MAP

  1. Oxygen (O2):

Food deteriorates due to physical, chemical and microbiological factors. For these reasons, in modified atmosphere packaging, oxygen is either excluded or the levels set as low as possible. The exceptions occur where oxygen is needed for fruit and vegetable respiration, color retention as in red meat, or to avoid anaerobic conditions in whitefish. One of the significant functions of O2 in MAP meats is to maintain myoglobin in its oxygenated form, oxymyoglobin. This is the form responsible for the bright red color, which most consumers associate with fresh red meat In MAP, oxygen levels usually are set as low as possible to reduce oxidative deterioration of foods.

  1. Carbon dioxide (CO2):

Carbon dioxide has bacteriostatic and fungistatic properties. There have been many theories regarding how CO2 exerts its influence on a bacterial cell. These can be summarized as follows-

  1. a) Alteration of cell membrane function, including effects on nutrient uptake and absorption.
  2. b) Direct inhibition of enzymes or decreases in the rate of enzyme reactions.
  3. c) Penetration of bacterial membranes, leading to intracellular pH changes.
  4. d) Direct changes to the physio-chemical properties of proteins.
  1. Nitrogen (N2) :

Nitrogen is an inert, tasteless gas, which displays little or no antimicrobial activity on its own. However, because of its low solubility in water and fat, the presence of N2 in a MAP food can prevent pack collapse. In foods such as nuts, removing oxygen to <%1 by nitrogen flushing helps prevent oxidative rancidity of fats. Nitrogen can also indirectly influence the microorganisms in perishable foods by retarding the growth of aerobic spoilage organisms

  1. Noble gases :

He, Ne, Ar and Xe are the members of this group. Ar is the main gas used in MAP,it can replace nitrogen to fill in wine bottleneck before corking, can prevent growth of the microorganism in foodstuff such as broccoli and lettuce.

Modification techniques:

  1. Gas flushing :

During a gas flush process, a harmless gas (usually nitrogen) is actively pumped into the bag before sealing to displace ambient oxygen. This is done to decrease the amount of oxygen inside the package, which will in turn decrease the rate of spoilage, as oxygen is one of the top killers of freshness.

  1. Barrier films:

Plastic films and foils are used to seal the MAP food packaging. Once Nitrogen or other gas flushes the Oxygen out from the package, the barrier film protects the food from further involvement with Oxygen. Packaging films are selected based on the characteristics of the food product and the permeability properties of the selected protection. Basically, the barrier is an extra layer of protection for preservation that maintains the package’s atmosphere.

  1. On-package valves:

One-way valves added to the exterior of packaging are another example of MAP allow certain gases to escape from the package without allowing any outside gases in. This is often done to release pressure created from off-gassing, which is when products release gases or other compounds. Most often used in the coffee industry

  1. Scavenger or desiccant packs :

Another example of MAP packaging is adding an oxygen scavenger or desiccant pack to the packaging. These small sachet type packages often contain a mixture of iron powder and ascorbic acid, and sometimes activated carbon. These ingredients act as catalysts or activators, absorbing ambient moisture and oxygen, thereby removing it from the packaging’s interior that houses the perishable product.

Example of gas mixture composition:

Different combinations of composition mixture are used for the preservation purpose. Few examples are given below-



Oxygen %

Carbon-di-oxide %


Raw Red meat




Hard cheese













Pros and Cons of Modified Atmospheric Packaging.




Longer shelf life

More expensive

 Enhanced visual appeal

 Less consumer base

Stays fresh longer

 Complicated to package

 No chemical preservatives

A higher level of quality assurance required


 Long-lasting flavor preservation

 Sustained nutritional content

Stays fresh longer


There are many advantages of MAP in fruit and vegetables, but the most obvious one must be shelf life extension. By decreasing the amount of available oxygen to the produce, the respiration rate and the rate of all metabolic processes are correspondingly decreased. This results in delayed ripening and senescence. Challenges in MAP includes the cost of packaging material, storage temperature and specific gas composition for a specific product. Every technology has its own pros and cons, and hence balance has be achieved in such a way that can assure safety and quality.