Insight on Evaporators Used in Food Industry

We use jam, condensed milk, milk powder, dried cheese powder in day-to-day life, but have you ever wondered how these things are processed? The food industry is booming and ready to eat meal is one of the reasons behind this. Evaporation is one of the important processing which is used by the food industries for the preparation of food products. In the food industry, raw materials are used which contains more water than required in the final product. The easiest way to remove water/concentrate the food product is to use evaporators.

An evaporator is defined as a heat exchanger intended to heat a given product and separate water by evaporation. Evaporators are widely used in the food manufacturing industry to remove the portion of water from food products. This helps in increasing the total solid content in food products and reduction in the bulk weight which ultimately helps in the facilitation of the transport.

The process of evaporation is different from drying and dehydration as the liquid obtained from it is still in a form of non-solid liquid. Evaporation only serves as the first step in making the finished product into concentrated liquid and dried goods. Powdered ingredients like dairy whitener, whey powder etc. are prepared by spray drying. Hence, we can say that powdered products are a combination of both techniques.

Working Principle

Evaporation is a process in which simultaneous heat and mass transfer process occur resulting in the separation of vapour from a solution. Evaporation occurs where molecules obtain enough energy to escape as vapour from a solution. The rate of escape of the surface molecules depends primarily upon the temperature of the liquid, the temperature of the surroundings, the pressure above the liquid, surface area and rate of heat propagation to the product. It is thus a thermal separation or thermal concentration process that begins with a liquid product and ends up with a more concentrated, but still liquid and still pumpable concentrate as the main product from the process.



Reason for Installation of Evaporators

 There are several reasons for concentrating food liquids:

  • To reduces costs for storage and transportation.
  • To induce crystallization.
  • It may be used as an economical preparatory step for subsequent dehydration as in the cases of spray drying, vacuum drying, freeze-dried, crystallization and mixing.
  • To reduce water activity to increase microbiological and chemical stability.
  • Recover valuable substances and by-products from waste streams.

 Components of Evaporator System 

  1. A heat source: It is generally comprised of a heat exchanger for the evaporation of water.
  2. An evaporation vessel: It drives out water from the product as vapor.
  3. A vapor separation vessel: It separates vapor and product.
  4. A vacuum system: It draws water vapor out of the separation vessel. This vacuum also reduces pressure in the evaporation vessel, which reduces the boiling point.



Evaporators may operate singly, or several may operate in series. Each one is referred to as an effect and in multiple-effect systems, the product output from one effect is the feed for the following effect. Similarly, higher-temperature vapor driven out of the product in one effect is used to heat a lower-temperature product in another. Efficiency is gained by using multiple-effect systems.


Types of Evaporators Used

  1. Circulation or Vertical Tube Evaporators

Tubes carrying the steam internally are placed vertically in the bottom of the cylindrical evaporator, chamber. It is popularly known as Calandria evaporator. As a single pass through the tube heat exchanger is usually not sufficient to achieve the required degree of concentration, the product is returned through the circulation tube.

  1. Horizontal Tube Evaporators

In certain conditions, if, for, example, there is limited vertical space for installation, the tubular heat exchanger can be used as a horizontal evaporator. To ensure that both the top and the bottom tubes are covered with liquid, the evaporator must be operated in a flooded condition, i.e., the feed inlet must be positioned above the uppermost tube. Steam enters a chest on one end of the tubes, moves through the tubes and the condensate is removed from the chest at the opposite end while the vapour is removed from the top of the cylindrical chamber.

  1. Plate Evaporators

The plate evaporator is characterized by a large heat exchange surface occupying a relatively small space. Like the plate heat exchanger, it is constructed from profiled plates with the condensing steam used as a heating medium and the evaporating product passing between alternate pairs. The capacity of a plate evaporator can be altered by changing the number of plates.

  1. Forced Circulation Evaporators

When highly viscous products are to be evaporated, the forces which normally move the liquid along are not sufficient to transport the product satisfactorily. Centrifugal or positive pumps are used for the forced circulation of viscous liquids. The operation is only economical if the product has been pre-concentrated on a simpler evaporator.

  1. Falling Film Evaporators:

The heat exchange surface in a falling film evaporator consists of a bundle of tubes down which the product flows. Depending on the design, the tubes are 4-10 m long and have a diameter of 25-80 mm. The falling film evaporator has become of great importance to the dairy industry. The relatively short contact times and the possibility of accurate temperature control ensure mild evaporating conditions.

Maintenance Tips to Improve Energy Efficiency

Regular maintenance will help ensure that equipment serves a long, useful life and operates efficiently. The following suggestions will help keep your evaporators operating efficiently:

  1. Prevent air leaks into the evaporators to minimize venting rates. Air is a non-condensable gas and must be vented to keep evaporation vessel pressure from increasing.
  2. Clean heat transfer surfaces to allow the most efficient use of energy to evaporate water from the product.
  3. Inspect and repair or replace wet or damaged insulation as it is found. Also, make sure insulation is the appropriate thickness.
  4. Keep the vapor separation vessel clean to maintain product yields and pressure profiles.
  5. Prevent water leaks into the system to avoid diluting the product, which defeats the process.

Evaporators are mainly used to concentrate a weak solution by using a certain heating medium. Most commonly used heating medium is steam and generally, vacuum-based evaporator systems are preferred in the food industry as it lowers the boiling point and thus increases the process efficiency and lower downs the energy usage. Selection of material concentration, product flowability, product characteristics, heat sensitivity, capacity is some of the important factors which are required to be considered for the designing of evaporators. Evaporators must be designed in a way that they can also discard non-condensable gases and material that originate as dissolved material in the evaporator or from leaked air into the evaporator.






Insight on Importance of Hold and Release Program of Non-Conforming Product Used in Food Industry

Hold and Release program is a preventive measure program which safeguards the company against product recall and provides assurance that non- conformity ingredients/products are not used at any stage of the food supply chain. This program is a great way to ensure that the finished product that your food business is sending out into the marketplace is not only going to be safe, but also meet the desired product attributes. A food product can be classified as safe when it does not contain any biological, chemical, or physical hazards.

Non-conforming product is defined as a product at any stage in the process that does not meet agreed food safety and quality criteria. This can apply to any raw materials, ingredients, packaging materials, work-in-progress or finished product. It can also apply to any other material used in the facility that can impact product safety or quality, e.g. cleaning chemicals, processing aids, equipment.

Elements of Hold and Release Program 

Hold and Release Planning:

Hold and Release plan should include:

  • a written detailed plan that includes plant-specific procedures to be used to implement an effective program. 
  • Include a tracking and documentation system that identifies the product(s) placed on hold, and the release or appropriate disposition process upon receipt of test results.
  • Provide written justification for production issues (e.g., raw materials, product shelf-life, physical space to hold product, ability to fill customer orders, line separation) to support the requested notification time prior to agency sampling.


Marking/ Tagging System:

Markers and Tags helps in distinguishing products held/ rejected from other products. Examples of identification systems include:

  1. Use of color-coded shrink-wrap,
  2. Use of color-coded tape (like crime scene tape), or
  3. Use of color-coded tags

Address the tracking of product held (e.g., where is it located, if transported offsite – carrier, delivery information, location at off-site storage).


Maintaining Control of Product(s) being Held:

Establishments should have following procedures in place to prevent products being held from entering production area:

  1. If possible, store the product being held away from other products.
  2. Clearly identify the product being held to distinguish it from other products to prevent it from being shipped accidentally.
  3. Protect unpackaged product from cross-contamination.
  4. Track the location of the product being held during storage and transportation.


 Test and Hold programs should:

  1. Provide a written, detailed description of the entire test and hold procedure.
  2. Ensure control of the product(s) being held.
  3. Include a written agreement with all off-site storage facilities used to store product while it is being held pending test results.
  4. Document Certificate of Analysis (COAs) and any test results for any raw materials being used in raw, ground product.
  5. Document COAs, any test results and letters of guarantees from suppliers of raw materials.
  6. Provide a documentation system that:
  • Identifies product(s) being held
  • Includes date and time of sample collection
  • Includes product name
  • Includes raw material information
  • Includes production or lot code
  • Includes product volume
  • Includes plant contacts
  • Includes the release of product or appropriate disposition
  • Document sanitation and reinspection procedures designed to ensure the separation of product runs or production lines.

Clearly, food control involves many difficult issues. Some of these are highly technical, while others are partly technological and partly political. The mutual goal should be to resolve these questions in a way that considers the needs of governments, consumers, and industry. For governments, there is the need for enforceable standards that are convincing to both consumers and industry. For consumers, food control systems must provide meaningful protection against real and important hazards. Finally, industry needs standards that permit flexibility and efficiency in producing and marketing foods that will serve their customers – the world’s consumers.




Tanks used in dairy industry

In dairy industries, tanks can be defined as an industrial sized, sanitary containers, which are either used for holding or temporary storage of dairy ingredients, or they are used as an vessel for carrying out intermediate processes like mixing, cooling and heating.

In this video lecture, Disha Sinha (Process Engineer) at PMG Engineering introduces the concept of tanks in dairy industry, and its types depending on the purpose in dairy industry.

Essential Components of Food Recall Program in a Food Industry

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. 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 because of a food business’s internal testing and/or auditing.


Product Recall Program

A recall program is a written action plan that is carefully constructed, tested, and evaluated to ensure efficiency. It is the safety net that can prevent consumers from buying or eating a potentially harmful food product. Having an efficient recall program may reduce a company’s liability, while a non-existent or poor recall program can have serious economic and legal consequences.

Components of Product Recall Program

Recall Team

Identifying recall team members and assigning recall duties enables the recall procedures to be conducted quickly and smoothly. The recall program should also identify the person who will coordinate the recall. The recall coordinator should have the authority to call upon other recall team members as needed to address the issues at hand. Recall team should include people responsible for decision making, quality assurance, technical advisory, media communication, complaint investigation, contacting customers, contact person from specified regulatory authority (FDA, FSIS or CFIA) and legal counsel. The list of people that make up your team should be reviewed and updated on a regular basis.

Complaint file

When a complaint is received, it is important to record the details and start an investigation either at your plant or your distribution facility. Early action on your part may enable you to identify potentially unsafe products and correct problems or enable you to stop selling the product until it is determined that it is safe.

Recall Contact List

If you suspect that you have sold or distributed an unsafe or violative food product, it is your duty to contact your regulatory agency immediately, as they can assist with the investigation and the collection of information to help make the right decision. A recall program should contain a contact list with the names, phone and fax numbers of the appropriate regulatory agencies.

Traceability System

Being able to determine which products need to be recalled allows you to limit the scope of a recall. If the specific affected products cannot be identified, you will need to broaden the scope of the recall, often recalling more products than necessary, which results in more financial losses. If the products are incorrectly identified, another recall may be necessary. As a Distributor, traceability of products involves record-keeping procedures that provide you with the information of products that have been received and distributed. If you are a Manufacturer, additional traceability procedures that show the route a raw material took from the supplier through production to the final product, and then on to customer/distributor are necessary.

Production amounts (Manufacturers)

In case of a recall, a company must ensure most of the affected product is removed from the marketplace. Having an accurate record of how much product has been sold, and how much is still on the premises, helps to ensure that all customers are notified of the recall. This means documenting the amount of each lot of each product manufactured.

Shipping and sales records

Maintaining accurate shipping and/or sales records is crucial because they can enable a company to limit the recall to only the customers who received the affected products.

Recalled product Records

It is beneficial to develop recall product records to ensure that recalled products are controlled and do not get into the hands of customers. Such records should include the name of the product being recalled, the amount, the date the product has been recalled and the corrective action taken for each product.

Recall Procedures

Every recall plan should contain a step-by-step explanation of what to do when a product needs to be recalled. Following this plan will help food manufacturers and distributors ensure that important steps are not overlooked during this time of crisis. Recall procedures should be readily available and should explain product coding, product traceability, and production and distribution records. Develop all necessary forms to be used in case of a recall, as well as a media release form if necessary.

The steps in any recall are similar for all products. For each recall, the processor should:


Recall effectiveness

A company recalling a product is responsible for notifying all customers who bought the affected products. They should also verify that all customers have stopped the distribution of the affected products, and that all recalled products have been returned to the processors or distributors’ control or other designated area as instructed in the recall notification.

Testing the recall program

Mock recalls test a company’s ability to recall products without actually recalling them. Mock recalls are strongly suggested and should be tested on a regular basis. The goal is to be able to identify every affected lot, know exactly where it is at any point in the process, and know who to contact to bring it back. Many a times mock recall can be an eye-opener for the food processors who thinks that their recall program is full proof. Mock recalls should test both product-tracking and ingredient-tracking systems. Results of the practice must show that a manufacturer/distributor is able to handle a 95-100 % of recall situation.

At first instance food recalls are seen as a public health issue only, but they are also responsible for significant economic loses 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 concluded that it can be one of the biggest threats to profitability, if not managed properly.



Manufacturing Process of Khoa- Insight

 Among the indigenous milk products, khoa occupies first position among various Indian dairy products and it also forms a base for number of sweet delicacies. Khoa is a popular product throughout India and is called by different names in different regions like mawa, khoya, palgova, kava, etc.

Khoa is the product obtained from cow or buffalo (goat or sheep) milk, or a combination thereof by rapid drying containing milk fat content not less than 30 percent on dry weight basis of the final product. Khoa is a heat coagulated, partially dehydrated milk product which is obtained by heat desiccation of whole milk to 65% to 70% milk solids without the addition of any foreign ingredients, mostly in private and unorganized sectors of India. Due to its large-scale consumption nearly six lakh tones of khoa are manufactured annually, which is equivalent to 7% of India’s total milk production.

Chemical and Nutritive Content of Khoa

The market samples of khoa show wide variations in chemical composition. Certain times, the market samples fail to meet the minimum legal standards also. To provide minimum legal standards in khoa, the minimum fat content of 4.4% in cow’s milk and 5.5% in buffalo milk should be maintained.

Khoa is a rich source of energy, about 458 Kcal per100 g of the product. The food and nutritive value of khoa is extremely high. It contains large quantities of muscle building proteins, bone forming minerals, and energy giving fat and lactose. It is also expected to retain most of the fat-soluble vitamins A and D, and also fairly large quantities of water soluble B vitamins contained in the original milk.

Varieties of Khoa

There are three distinct varieties of khoa. They differ in their composition, body and textural characteristics and end use.


This variety is identified as a circular ball of hemispherical pat with compact mass, homogenous and smooth texture. It is characterized by pleasant and cooked flavor and is generally devoid of objectionable tastes like burnt, acidic etc. For production of pindi variety of khoa, heating is continued after rabri stage and with the help of a wooden ladle the soft grains are crushed, and the mass is worked out to a smooth textured product. After cooling, the khoa is molded into hemispherical molds to give its shape.


It is a raw (katcha) khoa characterized by loose but smooth texture and soft grains and sticky body. Dhap variety carries highest percentage of moisture over other varieties of khoa. For preparing dhap variety of khoa the heating should be stopped at rabri stage (thick mass) and leaving the product without much working.


This is characterized by the granular texture with hard grains of different sizes and shapes embedded in viscous serum. Slightly sour milk is preferred in the manufacture of this variety as it yields granular texture. Generally, the milk that is left over after the preparation of other varieties of khoa is converted into danedar variety of khoa. Sometimes citric acid (0.05 to 0.1%) or sour whey is added to milk at boiling stage to get granular texture.

Factors affecting the quality of Khoa

Type of milk:

Buffalo milk is generally used instead of cow milk for the manufacture of khoa due to its higher yield, softer body, and smooth texture. The khoa manufactured from cow milk have dry surface, yellow color, sticky and sandy texture.

Amount of free fat:

An optimum amount of free fat is necessary for desirable body and textural properties of khoa.

Total solid level:

There is significant positive correlation between total solid level milk and instrumental hardness, gumminess, and chewiness of khoa.

Working of Khoa:

The formation of large lactose crystals can be reduced through working of khoa when compared to un-worked khoa and working results in no perceived sandiness upon storage.

Equipments Used for manufacturing of khoa

Khoa is generally manufactured by halwais by continuous boiling of milk in a shallow iron or stainless-steel vessel to remove moisture. Traditional method used for the preparation of khoa has several disadvantages like poor and inconsistent quality and limited shelf life of about 5 days at 30°C.This leads to the attempts for up-gradation of the technology used for the manufacturing of khoa and following equipments were invented for the large-scale production of khoa.

1. Continuous khoa making machine

It consists of a preheating cylinder and two cascading pans. The preheater is a steam jacketed cylinder containing rotary scrapers which rotate at 120 rpm. The cascading pans are covered steam jacketed pans with open holes provided with spring loaded reciprocating type scrapper knives operating at 30 strokes per min. The milk is taken into the preheater and heated by steam at 3 kg/cm2 pressure. Here the milk is concentrated to about 30 to 35 per cent of total solids within 10 to 12 min. From the preheater, the milk enters the first cascading pan. Here the milk is further concentrated to about 50 to 55 per cent total solids within 7 to 8 min. The product then moves to the second cascading pan where its concentration is raised to the desired level i.e., 65-70 percent in 6 to 7 min. The steam pressures maintained in the two pans are 2 kg in this machine. The steam requirement is 50kg/cm2 and electric power requirement is 4 KW per hour.

 2. Scraped surface conical vat

A mechanized scraped surface heat exchanger with a conical vat process is developed for the batch production of khoa. Forty kg concentrated or 80 kg whole milk can be taken per batch which takes about 14 min and 50 min respectively. Steam pressure used is 1.5 kg/cm2. Product losses are high in this machine.

3. Contherm- Convap System

Attempts were made to prepare khoa on Contherm-Convap system which was developed by Alfa-Laval. This unit consists of two parts, a Contherm for heating the feed to about 95°C and Convap for concentrating milk to desired milk solids level. Concentrated milk with 35- 40%T.S. at the rate of 300-350 kg per hour can be fed to the machine. The steam pressures employed are 3 kg /cm2 in Contherm and 4 kg/cm2 in Convap.


4. Thin film scraped surface heat exchanger (TSSHE)

This machine has three jacketed cylinders placed in a cascade arrangement. This facilitates easy transfer of milk from one cylinder into the other. The scrapper speeds are 40, 55 and 69 rpm for the 1st, 2nd & 3rd stage respectively. The operating steam pressures used are 2.0 & 1.7 & 1.5 kg/cm2 in respective stages. One roller is used in the last stage in place of scraper blade which kneads the khoa to improve its body and texture. The first stage raises the milk solids level from initial 15 to 25 percent, the second stage to 50 percent and the third stage to 65-70 percent. The machine converts 50 kg of milk into khoa per hour at the operating pressures, specified. However, the capacity depends on the milk flow rate, steam pressure, total solid concentration of feed and final moisture required in the product. It is claimed that use of concentrated milk improves the capacity of the machine.

5. Inclined scraped surface heat exchanger (ISSHE)

An inclined scraped surface heat exchanger was developed for the continuous manufacturing of khoa. A scraper assembly is so built as to combines the functions of scraping and conveying. The SSHE has 3 jackets which operate at 1.0, 1.5 and 1.0 kg/cm3 respectively. Milk is previously vacuum pre-concentrated to 40 – 55% T.S and fed at the rate of 60-80 lit/hr. Feed temperatures between 10 – 80°C can be employed. Rotor speed used is 40 to 80 rpm.

Although so many technologies are developed for the production and storage of khoa, there is a still a need of investigation of chemical and physical aspects during manufacturing of khoa in order to understand factors responsible for quality. And all the known technologies of manufacturing of khoa should be transferred to small holder farmers who are the major contributors of milk production in India. So that they can increase their prices of products by producing products which will meet the modern quality standards



Processing of Edible Vegetable Oils

Oils of plant origin have been predominantly used for food-based applications. Plant oils not only represent a non-polluting renewable resource but also provide a wide diversity in fatty acids (FAs) composition with diverse applications. Besides being edible, they are now increasingly being used in industrial applications such as paints, lubricants, soaps, biofuels etc. In addition, plants can be engineered to produce fatty acids which are nutritionally beneficial to human health.

Vegetable edible oil refers to oil obtained from oilseeds and nuts through an extraction process. It can be extracted from various oil seeds such as mustard, coconut, soybean, peanut, rapeseed, cottonseed, sesame, etc. via pressing process. Plant based extracted oils are generally used for salad dressing, deep fat frying and pan frying.

Until the industrial revolution in the 19th century, rapeseed, linseed, olives, and nuts were the primary sources of vegetable oils. Today, the world market is dominated by palm and soybean oil, followed by rapeseed and sunflower oil. This has led to a change in the extraction and purification/modification processes. Originally, the oil extraction process consisted of cleaning, crushing, heating, and pressing only. But from 1900 onwards, solvent extraction was applied to recover the residual oil from the pressed cake or to replace the pressing process completely (e.g., for soybean oil). At the same time, the oil purification process changed from a simple decanting and filtration to a combination of neutralization with caustic, bleaching with active clay and deodorization at high temperature under vacuum with steam.

Commercial Process of Manufacturing Edible Vegetable Oil

In a typical edible oil processing plant oil is extracted from the seed first using mechanical extraction (expeller press) process followed by chemical extraction (hexane extraction) process. By using both methods less than 1% of the oil is left in the meal. Then the left out residual meal is sold as an animal feed raw material. Following are the steps involved for the processing of vegetable oil:

Step 1: Harvesting of Oil Seeds

Seed is planted and harvested as with any other crop. This is followed by the cleaning process, which removes unwanted materials such as soil and other seeds from the harvest. In some cases, it is preferable to shell the seed, removing hulls for a better-quality final product.

Step 2: Processing

At this point, if the seed is large, the seed is crushed or broken up into smaller pieces. These uniform pieces are then conditioned by heating before being pressed for oil. The two products of this process are the raw pressed oil and the press cake, which is the compressed dry material of the seed. The raw oil is filtered before moving on to the final steps.

Step 3: Solvent Extraction

Pressed cake is flaked and broken down for additional oil extraction. The flakes are ground up and mixed with hexane to produce a slurry, which is heated. During heating, the hexane evaporates, and is collected for further use. While being heated, the meal releases the remaining oil, which is mixed with a small amount of hexane that did not evaporate.

Step 4: Refining

It is a combination of the following process steps for producing an edible oil with characteristics that consumers desire such as bland flavor and odor, clear appearance, light color, stability to oxidation and suitability for frying:

  1. Degumming: A pretreatment process applied to seed oils to reduce the phosphorus content. It is a two-step process with addition of water and/or acid to hydrate phospholipids. The phospholipids are subsequently removed by centrifugation.
  2. Neutralization: The purpose of neutralization is to reduce the concentration of free fatty acids to a maximum of 0.10% with the use of a diluted alkali solution, typically sodium hydroxide. This process can be applied batch-wise in stirred vessels and continuously by means of centrifuges. After alkali treatment, the oil is washed with hot water or treated with silica to reduce the residual soap level in the neutralized oil.
  3. Bleaching: The main purpose is to remove residual soap, pigments, and oxidized components. In this process, bleaching earth (activated clay and/or silica) is added to the oil as absorbent. The earth and absorbed impurities are subsequently removed by filtration. Addition of activated carbon in the bleaching process will also reduce the polycyclic aromatic hydrocarbon level. An acid pretreatment before bleaching earth addition will improve the removal of phosphorous (max 30ppm) and/or metals during the bleaching process.
  4. Deodorization: Under high vacuum the oil is heated to 180–240°C and brought in contact with stripping steam to remove volatile components and to create an odorless oil with a bland taste and increased storage stability. Also, free fatty acids can be removed during deodorization, at increased temperatures (220–270°C).

The process sequence of combined degumming/neutralization followed by bleaching and deodorization is called chemical refining, referring to the chemical removal of free fatty acids. The process sequence of degumming followed by bleaching with acid pretreatment and deodorization at high temperature is called physical refining, referring to the physical removal of free fatty acids (stripping). The physical refining process is generally preferred for low phosphorous oils (acid degummed seed oils and tropical oils) due to lower oil losses and less liquid effluent production.

Industry can design almost any fat or oil for a specific application by the use of various modification processes, such as hydrogenation, interesterification, fractionation or blending. Hydrogenation typically reduces essential fatty acid content and creates various fatty acid isomers, both cis and trans. The wide flexibility available to industry through the selection of raw materials and different modification processes allows for the production of oils at the lowest cost possible, an important aspect of food production.



Industrial Effluent Treatment Plant- An Introduction

Water is an essential part of any food manufacturing plant. It is used as an ingredient, coolant, CIP solvent or in many other chemical based reactions in companies. After the completion of manufacturing process, this influent gets converted into wastewater which gets expelled from industry as a byproduct which is also known as effluent. This effluent is defined as a mixture of both toxic and non- toxic materials and it generally contains 99.9% water and 0.1% solids. The main task in treating the wastewater is simply to remove most or all this 0.1% of solids. Effluent cannot just be disposed to the environment because of the harmful material it contains. Therefore, an effluent treatment plant comes into play. This is simply a procedure put in place to purify industrial wastewater to recycle it or dispose of it safely. Different companies have different wastewater composition and require slightly different effluent treatment plant.

A. Characterization of Wastewater

Physical Parameters of the Wastewater

Wastewater has physical characteristics such as temperature, solids, odor, and color. In plumbing work the temperature and type of solids in the wastewater are important considerations. Wastewater at high temperature will affect some piping materials and treatment units such as septic tanks. You may have to consider the use of an arrestor to pre-treat the wastewater.

Chemical Parameters of the Wastewater

Wastewater contains chemicals such as nitrogen, phosphorus, and levels of dissolved oxygen as well as others that may affect its composition and pH rating. Highly acidic or alkaline wastewater is probably trade waste and will require pre-treatment before discharge to the sewer. The chemical properties of wastewater may also affect the pipe material.

Biological Parameters of the Wastewater

This is the presence of microbial pathogens in the wastewater. Consists of microscopic flora and fauna which are pathogenic in nature and can transmit dangerous diseases such as typhoid, cholera and dysentery.

Therefore, ETP is designed to remove the physical, chemical, and biological materials present in the effluent.

B. Components of Effluent Treatment Plant:

Depending on the level of treatment the wastewater requires, an ETP is divided into four different levels each designed to remove a certain type of material in the effluent. There are four levels in wastewater treatment, each level designed in a way that by the time the process is complete, the water to be disposed to the environment is as friendly as possible. These levels are as follows:

Preliminary level

This aims at the removal of physical waste present in the effluent. This level involves physical processes such as sedimentation, filtration, aeration, flow equalization, clarification and screening.

Primary level

Aims at the removal of large solids and organic matter. It involves both physical and chemical processes. The same physical processes mentioned in the first level are utilized. The chemical process involves the addition of certain chemicals to improve the quality of the wastewater. These chemical processes include chemical coagulation, pH control by addition of HCI or sodium carbonate, chemical precipitation, flocculation, and dissolved air flotation.

Secondary level

Involves the removal of biodegradable organic materials and suspended matter. This level uses biological and chemical processes. The chemical processes are similar to level Biological processes involved are the suspended-growth process and the attached-growth/fixed-film process. The two biological processes can be used together or either one can be chosen.

Tertiary level

This level entails the removal of suspended and dissolved materials using the physical, chemical and biological process utilized together. The processes are as discussed in previous levels. Effluent treatment plants are a critical part of the manufacturing industries and other wastewater treatment plants. They keep the environment safe from hazardous materials through strict treatment protocols.

Effluent of food wastes are a significant contributor to nutrient and carbonaceous and nitrogenous waste discharge. Treatment of this food processing wastewater is complex and costly because of the contaminant loadings and the variability of the different wastes encountered in a plant. Industries including poultry and meat processing, dairy products and oil production generate high-strength wastes. While common wastewater treatment processes are used, there are constant developments taking place in treatment scheme so that wastewater can be economically converted into nontoxic effluent which can be discharged off into environment. In addition to reducing operating costs, ETPs are also considered environmentally friendly by reducing waste discharges and carbon footprints.



Insight on Manufacturing Process of Paneer

Paneer is an unaged variety of cheese, classified as a traditional Indian dairy product and is known to be one of the most popular party foods among vegetarians. Undeniably paneer is a versatile delight which happens to be the most loved main course, side dish and appetizer delicacy. No matter how you prepare paneer, its amazing taste can add soul to any party or occasion. Popularly consumed in South Asian subcontinents, especially in India; From appetizer to desserts, paneer can certainly take your food experience up by a notch. Interestingly, every year about 5% of milk is converted to paneer.

Indian paneer is the fresh and non-melting cheese, which is prepared by curdling of milk using some citric acid or any acidic vegetable liquid. The curdled milk is also called as chena or cottage cheese. The only minor difference between traditional Indian paneer and regular cottage cheese is that cottage cheese contains a little salt.

Paneer is obtained by the acid and heat coagulation of milk at a high temperature. Paneer contains large structural aggregates of proteins formed during the coagulation of milk in which milk fat and other colloidal and soluble milk solids are entrained with whey. According to FSSR, paneer shall not contain more than 70% moisture and the fat content should not be less than 50% of dry matter. Good quality paneer is characterized by a white color, sweet, mildly acidic flavor, spongy body, and a closely knit texture. Paneer has a high nutritional profile as it retains about 90% of the fat and protein, 50% of the minerals, and 10% of the lactose of the original milk. The proximate composition of paneer is 54% moisture, 17.5% proteins, 25% fat, 2% lactose, and 1.5% minerals.

Commercial Manufacturing of Paneer

Commercial production of paneer involves 6 process steps-:

Step 1: Milk Standardization

For commercial manufacture of paneer buffalo milk is standardized to 5.8% fat having 9.5% SNF (standardize the buffalo milk to a fat: SNF ratio of 1:1.65).

Step 2: Heat Treatment:

After standardization of milk, it is heated to 90°C without holding (or 82°C with 5 minutes holding) in a jacketed closed vessel known as Paneer Vat. Then milk is allowed to cool down to 70°C. Heat treatment of milk causes destruction of microorganisms, denatures whey proteins and retards colloidal calcium phosphate solubility.

Step 3: Coagulation and Draining of Whey

Coagulation is done at about 70°C by slowly pouring 1% hot (70°C) citric acid solution with constant stirring till a clean whey is separated (pH 5.30 to 5.35) and coagulum is allowed to settle for 5 minutes, after which the whey is drained off.

Step 4: Hooping

 The curd so obtained is filled into hoops lined with cloth.

Step 5: Pressing

Pressure is applied on top of the hoop at a rate of 0.5 to 1kg/cm2. The surface of hoops must contain holes to facilitate whey expulsion. Good quality product can be prepared by pressing for around 15 min.

Step 6: Dipping in Chilled Water

The pressed blocks of paneer are removed from the hoops and immersed in chilled water for 2-3 hrs. The chilled paneer is then removed from water to drain out. This step assists in developing texture and speeds up the cooling process. The water used for chilling should be of good bacteriological quality.

Step 7: Packing

Finally, paneer blocks are wrapped in parchment paper / polyethylene bags and placed in cold room at about 5 to 10°C.

Factors Affecting Quality of Paneer

  • Type of milk

Paneer prepared from buffalo milk will have desirable frying properties, body and texture as compared to cow milk. The cow milk paneer is too soft, weak, and fragile and during cooking it tend to disintegrate. However, cow milk and buffalo milk at 50:50 yields better product than cow milk. Paneer made from skim milk has chewy, rubbery, and hard body.

  • Quality of Milk

To obtain paneer of good quality, the milk must be fresh and free from off flavor. Growth of psychotropic organisms should be minimized to restrict the off-flavor development. Acidic milk having a titratable acidity of more than 0.20% lactic acid yields a product of inferior quality. The milk with COB positive and low acidity (sweet curdling) is not suitable for paneer making. Paneer made from such milk has weak body and texture, more moisture, acidic smell and not safe for human consumption.

  • Type and Strength of Coagulant

Citric acid is generally used as a coagulant. Lemon or lime juice or vinegar imparts a typical flavor to the product. The concentration of citric acid used for best results is 1%. A higher concentration may lead to a harder product with a higher loss of solids. For coagulating 1 kg of milk, about 2–2.5 g of food-grade citric acid is used. Naturally, soured whey cultured with Lb. acidophilus added at 2% and incubated overnight at 37°C reduces the requirement of citric acid and increases the recovery of solids without loss of quality.

  • Heat Treatment of Milk

The objective of heating the milk is to prepare the milk for rapid iso-electric precipitation, control the moisture content, develop typical body and texture, create conditions conducive to the destruction of pathogenic and other microflora present in milk and ensure safety as well as keeping quality of the final product. The milk is heated to 90°C without holding or 82°C for 5 minutes to maximize the total solids recovery. Whey proteins especially ß-lactoglobulin and a-lactalbumin form a complex with Қ-casein and retain with the curd thus increase the yield of the product. The high heat treatment imparts desirable cooked flavor by controlled liberation of sulfhydryl compounds.

  • Coagulation Temperature

It influences the moisture content of the paneer, an increase in temperature from 60° C to 86° C decreases the moisture in paneer from 59 to 49%. At 70° C, paneer has the best organoleptic and frying quality in terms of shape retention, softness, and integrity.

  • pH of Coagulation

The optimum pH of coagulation of milk at 70°C is 5.30-5.35. The moisture retention in paneer decreases with the fall in pH and consequently the yield also decreases. At pH more than 5.35 the paneer is incredibly soft with fragile and crumbly body texture. Optimum pH when cow milk is used for paneer preparation is 5.2.

Paneer represents a variety of Indian soft cheese, which is used as a base material for the preparation of many culinary dishes and is highly nutritious and wholesome. Most of the paneer is produced in unorganized sector in exceedingly small quantities using traditional methods. Reluctance to use modern technological processes has hampered the organized production, profitability, and export performance of paneer. Therefore, due to increasing demand for paneer, advancement is required in the manufacturing of paneer which will result in increased yield of paneer, reduction in production cost, and increase in shelf life of paneer as well as production of new varieties of paneer for health-conscious people.



Mycotoxin in Edible Nuts, oilseeds, and Legumes

Food commodities like nuts, oilseeds and legumes are major dietary constituents which are widely consumed across world in form of traditional food or as a functional ingredient in processed foods. These constituents also help in combating various lifestyle associated chronic disorders as these are enriched in dietary proteins, fiber, polyunsaturated fatty acids, and phytochemicals. However, these materials, due to their physical and chemical composition, are particularly susceptible to mycotoxin contamination due to the presence of filamentous fungi/molds. Mycotoxin contaminated can occur any time during supply chain, either during vegetation in the field or during storage, as well as during the processing.

Mycotoxin  based contamination appears to be one of the major causes for economic losses of food and feed stuff and generating health-related risks posing serious health threat to both humans and livestock. Mycotoxins are low molecular weight secondary metabolites that are naturally produced by certain molds in food products under warm and humid conditions. Mycotoxins appear in the food chain as a result of mould infection of crops both before and after harvest. Most mycotoxins are chemically stable and can survive food processing.  The adverse health effects of mycotoxins range from acute poisoning to long-term effects such as immune deficiency and cancer. Exposure to mycotoxins can happen either directly by eating infected food or indirectly from animals that are fed contaminated feed.

Several hundred different mycotoxins have been identified, but the most observed mycotoxins that present a concern to human health and livestock include aflatoxins, ochratoxin A, fumonisins, zearalenone and deoxynivalenol. The major toxigenic fungal genera are Aspergillus, Penicillium and Fusarium producing a diverse group of mycotoxins with adverse effects. Insect infestations and damage play a major role in fungal infection and mycotoxin contamination. Insect control either through pest control, breeding or genetic engineering of resistant cultivars and/or biological control through the application of non-toxigenic strains is a promising tool to reduce mycotoxin contamination.

A. Classification of Mycotoxin Flora:

Fungi contaminating nuts, oilseeds and legumes have been conventionally divided into two groups:

  1. Field Fungi: Field fungi are those that infect the crops throughout the vegetation phase of plants and they include plant pathogens such as FusariumAlternaria, and Botrytis  .
  2. Storage Fungi: This group include Aspergillus, PenicilliumRhizopusand Mucor genera that infect grains after harvesting i.e., during storage.

B. Types of Mycotoxins 

  1. Aflatoxins:

The aflatoxins are the major mycotoxin contaminants of peanuts, hazel nuts, pistachio nuts, almonds, brazil nuts, walnuts and therefore the most important mycotoxins entering the human food chain upon consumption. A. flavus and A. parasiticus are the major producer of this secondary metabolite. These are the family of closely related compounds which includes aflatoxin B1, B2, G1 and G2 and AFB1. AFB1 is considered as the most toxic one among mentioned classes of aflatoxins. Based on the acute aflatoxin poisoning in India, an LD50 of approximately 5mg/kg body weight has been proposed in humans.

  1. Ochratoxin A (OTA)

It is produced by P. verrucosum and P. nordicum and by a few Aspergillus species including A. carbonarius and A. niger. The mycotoxin occurs on a wide variety of food products including coffee, grapes, beans, chickpeas, and nut seeds such as pecans and pistachios. OTA exhibits immunosuppressive, nephrotoxic, nephrocarcinogenic and teratocarcinogenic effects. The formation of DNA adducts, and the induction of oxidative stress have been proposed as possible mechanisms involved in OTA nephrocarcinogenic, which was classified as a group 2B carcinogen or possibly carcinogenic in humans. Involvement of OTA in the development of chronic renal disease and kidney and urinary tumors have also been reported.

  1. Deoxynivalenol (DON)

It is one of the major trichothecene mycotoxins produced mainly by Fusarium graminearum, F. culmorum and F. crookwellense which mainly infects the food commodities like maize, millet, sorghum and soybeans and rice. The major acute toxic effect of DON is related to feed refusal, vomiting and severe gastrointestinal toxicity in animals. Other effects include teratogenicity, cardiotoxicity, and disruption of the immune system.

  1. Zearalenone (ZEA)

It normally co-occurs with DON and exhibits its activity by binding to estrogen receptors altering the estrogen responsive elements in the nucleus. ZEA also interferes with steroid metabolism and hence could be involved in the disruption of the endocrine system and has been shown to increase liver cell and pituitary tumors in mice. ZEA, α-zearanol and the type B trichothecene, 15-acetyl DON, are consistently detected in soybean oil.

  1. Fumonisins:

It is mainly produced by Fusarium verticilioides , F. proliferatum and  A. niger. It cause a wide variety of toxic syndromes in animals, and depending on the animal species could affect the liver, kidneys, lungs and brain. They have been associated with the development of liver and esophageal cancer and neural tube defects in humans. Fumonisins have been classified as apparent non-genotoxic carcinogens that exhibited their mode of action via the disruption of lipid biosynthesis and hence the structure and function of cellular membranes.

Exposure to mycotoxins needs to be kept as low as possible to protect the people. Mycotoxins not only pose a risk to both human and animal health, but also impact food security and nutrition by reducing people’s access to healthy food. WHO encourages national authorities to monitor and ensure that levels of mycotoxins in foodstuff on their market are as low as possible and comply with the both national and international maximum levels, conditions and legislation.



  7. Food Safety Management – A practical Guide for food Industry


3D Food Printing

3 D Printing has emerged as a promising technology that finds vast applications in many fields such as machinery, biomedicine, engineering but recently this innovative technology has gained a huge popularity in area of food manufacturing sector due to its various advantages like customized food designs, personalized nutrition, simplifying supply chain and broadening of the available food material with varied attractive color, shape, and size. It is an additive process in contrast to some conventional processes of manufacturing which are subtractive.

In conventional process like cutting, milling etc. the material is removed to form the required component, but in 3 D printing material is added as per requirement and design to be formed. Nowadays, it is studied at global level to attain new techniques related to process so that it can be feasibly translated on larger scale for production of high volumes of product. This technology requires printers or scanners for formation of component through this procedure. It is also known as Additive Manufacturing which takes digital input in the form of Computer Aided Design (CAD) model and creates solid three-dimensional parts through an additive layer by layer process.


The basic principle for 3 D printed food is solid free form fabrication i.e., the ability of food material to hold and produce a solid structure without getting removed. The extruder pen or the injector places in the layer as per the design sent from computer. The bottom layer is quickly solidified to build more layer on it. To complete this a laser guided system is widely used. Customization of 3D printing processes allow for mass customization – the ability to personalize products according to individual needs and requirements. Even within the same build chamber, the nature of 3D printing means that numerous products can be manufactured at the same time according to the end users’ requirements at no additional process cost complexity. The advent of 3 D printing has seen proliferation of products (designed in digital environment), which involves levels of complexity that simply could not be produced physically in other way. While this advantage has been taken up by designers and artists to impressive visual effects, it has also made a significant impact on market share for the companies.


A 3D food printer comprises a food-grade syringe or cartridge that holds material, a real food item. 3D printing requires hardware and software to work in collaboration. Advanced 3D food printers are equipped with user-friendly interfaces and pre-loaded recipes with designs that can be easily accessed by the computer or even with a mobile or IoT device. Let us now understand the process of manufacturing food via printer in brief:

  1. Printing the Model

Depending on the design data, provided the printer lays down several layers of powder, liquid, paper, polymer, plastic, or other material depending on the material required. Printer resolution describes layer thickness and X-Y resolution in micrometers. 3D Printers give designers and concept development teams the ability to produce parts and concept models using a desktop size printer.

  1. Finishing

Though the printer-produced resolution is sufficient for many applications, printing a slightly oversized version of the desired object in standard resolution and then removing material with a higher resolution subtractive process can achieve greater precision. In this process the supports would be dissolved which might be used to support overhanging features in the model to be printed.

Types of Printing Techniques:

  1. Extrusion Based Printing:

In this method, melted material or paste like slurry is extruded out continuously from a moving nozzle, and welds to the preceding layers on cooling. This type of 3D food printing applied in chocolate printing and soft materials printing such as dough, mashed potatoes, cheese, and meat paste. Additional structural objects used for supporting the product geometry is removed after completion of the printing process.

  1. Selective layer Sintering

This method applies a power laser to selectively fuse powder particles together layer by layer finally into 3 D structure. In this method each cross section is scanned individually for fusion of all powder ingredients present in that cross section. After scanning each cross section, the powder bed is dropped, and a new layer of powder is covered on top. This process is repeated until the desired structure is achieved. If any unfused powder is left during process, then it can be recovered for next printing. It allows to produce free-standing complex 3 D structures with higher resolution. This method is specially used for powdered materials such as such as sugar, fat, or starch granule (low melting point). Properties like particle size, flowability, bulk density, laser type and laser spot diameter are critical to the printing precision and accuracy of fabricated parts.

  1. Binder Jetting:

The binder jetting process uses two materials: a powder-based material and a binder. The binder acts as an adhesive between powder layers. The binder is usually in liquid form and the building material is in powder form. A print head moves horizontally along the x and y axes of the machine and deposits alternating layers of the build material and the binding material. After each layer, the object being printed is lowered on its build platform. This method has the potential to fabricate complex & delicate 3D structures and produce colorful 3D edible objects by varying binder composition. But this method can be only used for powdered ingredients.

  1. Continuous Jet Printer

In this method, ink is ejected continuously through a piezoelectric crystal vibrating at a constant frequency. To get a desired flowability of the ink, it is charged by the addition of some conductive agents. Ink is ejected out from heads under pressure exerted by valve. Generally, the printing rates of drop-on-demand systems are slower than that of continuous jet systems. Resolution and precision of produced images are higher. Generally, inkjet printing handles low viscosity materials that do not possess enough mechanical strength to hold 3D structure. For formulation of food ink food hydrocolloids plays a vital role. A hydrocolloid is defined as a colloid system wherein the colloid particles are dispersed in water. A hydrocolloid has a colloid particle spread throughout water and depending on the quantity of water available that can take place in different states e.g., Gel or sol (liquid). Food Hydrocolloid can form and hold 3 D structure easily.

3D printing is a ground-breaking technology that can improve the nutritional value of meals and even address hunger issues in countries where fresh and affordable ingredients are inaccessible. Therefore, global food industry should adopt 3D printing technology to make food production more efficient and sustainable.