From tradition to technology: Heating methods in India's food industry

When purchasing packaged foods, many of us wonder if the product is hygienically safe or retains quality well beyond packaging. What truly impacts food safety, however, is the technology behind its packaging and preservation. In India, traditional techniques like sun-drying and adding preservatives have long been used to extend shelf life. Yet, with increasing demand, new solutions have emerged to better preserve food quality and freshness.

Heating is one of the most widely used and trusted methods for preventing spoilage, valued by both small and large food processors alike. In this article, we explore various heating technologies essential to enhancing hygiene, production speed, and shelf life in India’s food processing sector.

Food has always been vulnerable to contamination, a major challenge since the dawn of civilization. Our ancestors often suffered from gastrointestinal diseases due to the consumption of contaminated food resulting from inadequate storage and preservation methods. The advent of fire and cooking significantly reduced the risks of microbes and toxins in food. However, these risks could not be entirely eliminated, as early cooking methods primarily focused on fish and meat.

Over time, various methods for preserving and storing food emerged to maintain its quality, including sun drying, fermentation, and freezing in snow. To extend the shelf life of food and enhance efficiency, several techniques have been developed and refined, such as heat treatment, drying, freezing, extraction, mixing, and the use of preservatives. Thermal or heating methods are the most widely used preservation techniques in both household practices and industries.

Importance of Thermal techniques

Thermal methods for food preparation and preservation use a combination of temperature and time to kill harmful micro-organisms. Heat disrupts their cell walls by affecting the proteins, causing them to break down. Thermal processing also destroys natural and microbial toxins. Microorganisms are destroyed based on their heat tolerance, with psychrophiles and mesophiles easily killed above 50°C, while thermophiles and extremophiles may need temperatures over 130°C. Spore-forming bacteria can sometimes survive even at high temperatures. The primary goal of heat processing is to extend the shelf life of food by stopping spoilage from microbes, spores, toxins, and enzymes. Heat can be applied using air (dry heat) or water (wet heat).

According to a report by the Ministry of Food Processing Industries (MOFPI), India’s food industry is projected to reach a market size of $535 billion by FY 2025-26.

Currently, the sector represents 10.4% of India’s exports and employs 11.6% of the national workforce, with an additional 5.1 million people supported by the unregistered segment. These figures highlight a significant opportunity for advancements and innovations in heating methods and solutions within food processing.

Thermal processing technologies

Thermal processing is used to prepare different varieties of food and to achieve a prolonged storage life of food. The understanding of the thermal characteristics of food is crucial as they influence the overall efficiency of heat transfer.

Below are some of the primary thermal technologies used by food processing industry in India:

Blanching: Blanching is a unit operation before freezing, drying and canning that is applied to fruits and vegetables with the primary objective to inactive enzymes. As these naturally occurring enzymes cause ripening, food spoilage, deterioration of nutritional quality, off-flavour development, browning and discoloration.

It is not a preservation method but a mild heat treatment or pretreatment method that is usually carried out after the preparation of food, but before processing. The process involves rapid heating and cooling of food to a predetermined temperature with a specific holding section before the product enters into the cooling section. This pretreatment process has several benefits like softening tissue, expelling respiratory gases, eliminating undesirable flavour, improving color and more. Common types of blanchers include – Steam blanchers, Hot water blanchers and Microwave blanchers.

Pasteurization: Pasteurization is a mild thermal treatment widely applied on milk and juices at temperatures below 100 degrees. The primary objectives of pasteurization involves elimination of pathogenic and spoilage (souring) bacteria from foods, thereby preventing disease and sustaining quality of food. Pasteurization can be defines as the process of heating every particle of milk or other liquid foods at a specified temperature for a specified time in well-operated equipment followed by immediate cooling. Based on the type of equipment used, pasteurization can be classified into various categories like – Batch pasteurizer and Continuous pasteurizer.

Sterilization: Sterilization in food preservation involves destruction or elimination of all viable organisms from the food product. It involves the destruction of microorganisms including bacteria (both spore-forming and nonspore forming), yeast, mold and virus and allows food to be stored and distributed at ambient conditions for an extended period. Sterilization of food product is done at temperatures ranging from 115 -135 degrees for a certain period followed by cooling.

In sterilization, pH of the food is a vital parameter to consider in determining its severity.?Commercially, sterile foods are generally hermetically sealed to prevent recontamination. As the oxygen level is lowered during the evacuation process, obligate aerobes (microorganisms that require oxygen) cannot survive, and spoilage caused by these microbes can be prevented. Types of sterilizers include – Batch sterilizers and Continuous sterilizers.

Ultra-high temperature processing (UHT): UHT processing also termed as aseptic processing is a sterilization method commonly used in a broad range of liquid foods like milk, wine, fruit juices, concentrates, creams, salad dressing etc. A sterile environment has to be maintained for the filling of sterile product in to the pre-sterilized containers so that High Temperature Short Time (HTST) is possible.

The Food and Drug Administration (FDA) defines UHT pasteurization as “the thermal processing of milk at or above 138 degrees for a minimum of 2 seconds to produce a product for extended shelf-life under refrigeration.” Therefore it gives an additional advantage of a minimum of 6 months storage life without refrigeration.

Dehydration of foods: Drying or dehydration is one of the ancient thermal food preservation methods which can simply be defined as the removal of moisture content from the food by evaporation or sublimation to obtain a solid product with low water activity. Dehydrating of food products is crucial as low moisture content inhibits microbial growth and enzyme activity that causes food deterioration.

Moreover, drying also minimizes the weight and bulk of the products which in turn reduces the transportation cost and storage cost. It also helps preserve seasonal foods for later use.

The table below lists the principal type of dryers used in the food industry:

Ohmic and microwave heating: In Ohmic heating, heat is produced in the material due to resistance created by the current supply. It requires quick and continuous constant heating that results in less thermal damage in the food product and uniform rapid heat transfer thereby retaining flavour, color and textural attributes of the food product.

Microwaves meaning “very short wave” are electromagnetic waves of 300 MHz and 300 GHz frequencies which can be reflected or absorbed based on the dielectric properties of the materials. When high-frequency microwaves interact with charged particles in the food, the dipoles of the material rotate to align themselves with the electromagnetic field, causes intermolecular friction and collision between the ions.

The main advantages of microwave are that it heats the food rapidly with no overheating of the surface of the food which leads to minimal heat damages and no browning of the food surface.

It may be noted that although diverse heating systems in food processing offer substantial benefits, certain challenges persist for the industry. Key challenges include high initial costs, energy demands, and regulatory compliance. Many small and medium-sized enterprises (SMEs) face financial constraints that hinder investments in modern heating systems, such as energy-efficient boilers and heat recovery units, despite their potential for long-term savings.

Furthermore, food processing is energy-intensive, necessitating advanced technologies that are not only efficient but also cost-effective to balance energy consumption with operational costs. The stringent regulatory framework surrounding food safety and emissions standards adds complexity, as heating technologies must comply with both local and international guidelines, complicating integration efforts.

A lack of skilled labor to manage and maintain these advanced systems is another common hurdle, especially in rural areas, where access to reliable electricity is also a concern. This skills gap can lead to operational inefficiencies or increased maintenance costs, adding to the overall challenge of adopting these advanced systems effectively.

Future Trends in Heating Technologies for Food Processing

Heating technologies for food processing in India are evolving rapidly, focusing on energy efficiency, sustainability, and minimizing the carbon footprint. Key trends shaping the future include:

1. Industrial Heat Pumps: Heat pumps are gaining traction in the food processing sector due to their energy efficiency and capacity to reduce greenhouse gas emissions. These systems are especially beneficial in processes requiring moderate temperatures, such as pasteurization, sanitation, and evaporation. While high upfront costs and limited temperature ranges pose some challenges, advancements are broadening their usability. The integration with renewable energy sources like solar and geothermal is anticipated to further enhance their potential in food processing facilities.
2. Electric Heating Solutions: Electric infrared and induction heating technologies are becoming popular for their precision and ability to heat food products quickly and evenly. They reduce energy consumption and work well for processes that require controlled, high-intensity heat. These solutions are particularly suited for applications like drying, baking, and roasting and are adaptable for different processing scales
3. Sustainable Processing Technologies: Environmentally-friendly methods like high-temperature short-time (HTST) processing, freeze-drying, and aseptic processing are being increasingly adopted. These techniques not only reduce the energy required for heating but also help in preserving the nutritional quality of food products , aligning with consumer demand for healthy and sustainable foods.
4. Digital and Smart Solutions: Advances in AI and IoT are transforming heating processes in the food industry. These technologies enhance monitoring, predictive maintenance, and efficiency optimization, allowing real-time adjustments and better energy management. This shift supports both cost savings and a lower environmental impact, helping companies meet sustainability goals.

The food processing industry is rapidly innovating to tackle challenges in efficiency, sustainability, and safety, while adapting to evolving consumer demands. Emerging technologies, including industrial heat pumps, AI-driven systems, and sustainable processing methods, are shaping the future of food manufacturing.

By adopting these solutions, processors can deliver high-quality, safe foods and stay competitive. In 2024, the industry is marked by sustainable practices, farm-to-fork strategies, advancements in food safety, and a focus on food as medicine. As these trends gain momentum, the industry moves toward a more resilient, transparent, and consumer-centric future.

Indusfood Manufacturing 2025 is the ultimate platform for the F&B industry, bringing together top suppliers, innovators, and decision-makers under one roof. As the largest supplier exhibition in the sector, it offers unparalleled opportunities for networking, learning, and business growth. Exhibitors can showcase their latest products, technology, and services to a highly targeted audience of potential buyers, partners, and investors.

Meanwhile, visitors will gain direct access to cutting-edge innovations in food processing, packaging, ingredients, and hospitality equipment, all designed to boost efficiency, sustainability, and profitability.

With four sector-specific exhibitions in one comprehensive trade fair, this is the perfect event to explore trends, expand business networks, and discover solutions that will define the future of the F&B industry. Join us at Indusfood Manufacturing 2025 from January 9-11 at Yashobhoomi, Dwarka, and take your business to the next level!

For exhibition opportunities, contact Apurva Jain, Assistant Director, TPCI at +91 97113 16222 or [email protected] .

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