Factors affecting shelf life of Food Product

After manufacturing of any food products, it retain its desired sensory, chemical, physical, functional or microbiological characteristics. The timeframe till a product can hold these characteristics defines the shelf life of the product.

In this video lecture, Veena Mishra (Process Engineer) at PMG Engineering introduces us to the topic Shelf Life and outlines the various factors influencing the product shelf life.

Corrective Action Preventive Action (CAPA)

CCAPA is a process which investigates and solves problems, identifies causes, takes corrective action and prevents recurrence of the root causes. The ultimate purpose of practicing CAPA is to assure no problem or issues to occur again in any facility.

In this video lecture, Veena Mishra (Process Engineer) at PMG Engineering discuss about the requirements, importance and implementation of CAPA in food Industry.

Calibration Measurement and Monitoring of Equipment

Instrument calibration are an integral part of any operation in manufacturing facilities and testing laboratory. They are vital for data quality assurance.

In this video lecture, Veena Mishra (Process Engineer) at PMG Engineering outlines the basic requirements for the calibration and monitoring instruments based primarily on standard monitoring methods.

Shelf life of Foods

What is Shelf Life?

 The reference to “shelf” clearly implies that the term is related to the commercial life of the product, thus to a packaged product, delivered through the common routes of distribution, not to a generic, “natural life.”

Shelf life is defined as the period of time under defined conditions of storage, after manufacturing or packing, for which a food product will remain safe and be fit for use. During this period, a food product should retain its desired sensory, chemical, physical, functional or microbiological characteristics and, where appropriate, comply with any label declaration of nutritional information when stores according to the recommended conditions. Therefore, it is obvious that shelf life is a very important and multifaceted requirement of all manufacturers and processed food products.

The safety of food is both a fundamental and legal requirement. It follows that all food product offered for sale must be safe although they do not necessarily have to be of the highest quality.

Since shelf life is such an important requirement, it should be of interest to everyone involved in the food chain. There is the growing realization that a high standard of food safety can only be achieved by adopting a comprehensive and integrated approach, covering the whole of the food chain “from farm to table”. At the other end of the food chain, consumers, too, have a significant part to play. For instance, by minimizing the exposure of foods to high temperatures, particularly during summer months, and by observing carefully any recommended storage and usage instructions, consumers are ensuring that the intended shelf life of their food will not be reduced.


Who is responsible for determining the shelf life?

The responsibility for determining the shelf life of the product lies with the manufacturer or the packer. While ideas for new products and for improvements to existing products can originate from within a food business and from external sources such as a current or prospective customer, shelf-life evaluation and testing as very much integral parts of every product development programme. Today, almost without expectations, retailers do independently evaluate the shelf life of food products, particularly their own-label ones.

Labelling of shelf life                            

Food labelling regulations that apply to all food that is ready for delivery to the ultimate consumer or to a catering establishment, subject to certain expectations, is that it should be marked labelled with the appropriate minimum durability indications.

  • In the case of food that is highly perishable and in consequence likely after a short period to constitute an immediate danger to health, a “use by” date.
  • In the case of food other than one specified above, an indication of minimum durability, a “best before date”.

The ‘best before ’ date and the ‘used by’ date must be followed by any special storage conditions which need to be observed, such as ‘keep refrigerated at 0°C to +5°C’ or ‘keep in a cool, dry place”. The date of minimum durability is defined as the date until which the foodstuff retains its specific properties when properly stored.


Food that requires ‘use by” dates are following:

  • Dairy products, e.g. dairy-based desserts.
  • Cooked products, e.g. ready-to-eat meat dishes, sandwiches
  • Smoked or cured ready-to-eat meat or fish, e.g. hams, smoked salmon fillets.
  • Prepared ready-to-eat foods, e.g. vegetable salad such as coleslaw.
  • Uncooked or partly cooked pastry and dough products, e.g. pizzas, sausages rolls.
  • Uncooked products, e.g. uncooked products comprising or containing either meat, poultry or fish.
  • Vacuum or modified packs, e.g. raw ready-to-cook packed in modified atmosphere.

The range of product which is given ‘use by’ date differs from country to country. It is the manufacturers and processor’s responsibility to decide to which category their products belong and whether a ‘use by’ or ‘best fore’ date is an appropriate indication. In general, the date must be given as a day, month, and year.

For the ‘best before’ date category, the following forms of durability indication are allowed:

  • Food that will not keep for more than 3 months- ‘best before’ followed by the month and the month.
  • Food that will keep more than 3 months but not more than 18 months- ‘best before end’ followed by the month and the year or the year only.
  • Foods that will keep more than 18 months- ‘best before end’ followed by the month and the year or the year only.

Since food deteriorates continually rather than suddenly, the ‘best before date’ does not automatically mean the food is not fit for consumption or losses all its acceptability immediately after the date.

Once a date mark either ‘use by’ or ‘best before’ is set and declared, it becomes a contract between the food company and its customers to the effect that, provided the food is stored according to the recommended conditions, it should last at least as long as its states shelf life.

Shelf life is defined as the length of time a product may be stored without becoming unsuitable for use or consumption. Shelf life depends on the degradation mechanism of the specific product. Most can be influenced by several factors: exposure to light, heat, and moisture; transmission of gases; mechanical stresses; and contamination by things such as microorganisms.


  1. https://www.medallionlabs.com/blog/food-manufacturers-shelf-life-testing/
  2. https://www.eurofinsus.com/food-testing/services/testing-services/shelf-life-and-stability/
  3. https://en.wikipedia.org/wiki/Shelf_life#:~:text=Shelf%20life%20is%20the%20length,not%20yet%20unfit%20for%20use).
  4. https://www.google.com/url?sa=i&url=https%3A%2F%2Fonethird.io%2Fdifferent-types-shelf-life-prediction-technology%2F&psig=AOvVaw0j8ZYnI7XIqqbkVwFaKVr4&ust=1620468750721000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCNi5wNiqt_ACFQAAAAAdAAAAABAD
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  7. https://www.google.com/url?sa=i&url=https%3A%2F%2Fpbfy.com%2Fblog%2Ffood-preservation-and-shelf-life-is-flexible-packaging-right-for-you%2F&psig=AOvVaw1jxsjovNidM3nX0y5r0UAQ&ust=1620467204601000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCNCCp4Klt_ACFQAAAAAdAAAAABAK


Concept of Food Surveillance

A Food Surveillance Program helps control and prevent food hazards. It is a critical component of the food safety assurance programs and intends to evaluate the safety levels in our food supply. Inspectors of the statutory bodies take samples at import, wholesale, and retail levels for microbiological, chemical, and radiation testing. Microbiological testing covers both bacteria and viruses, while chemical testing includes natural toxins, food additives, and contaminants, while radiation testing detects any harmful radioactive substances.

The food surveillance system is an instrument for the formulation, modification, and application of a country’s food and nutrition policy. Such surveillance intends to provide information on which policy decisions can are made. In many countries, the food and nutrition policy is also an official policy. Since such a policy affects several different sectors, a food and nutrition surveillance system is needed to collect, analyze and interpret information from these various sectors.

Monitoring can be defined as “the recording and analysis of routine measurements, aimed at detecting changes in populations’ environment or health status”.

Surveillance can be defined as “the ongoing systematic collection, collation, analysis, and interpretation of data, followed by the dissemination of information to all those involved so that directed actions may be taken” (WHO/CDS/CSR).

Surveillance refers to a specific extension of monitoring where obtained information is utilized to take measures if certain threshold values related to disease status have been crossed. The main objectives of surveillance are outbreak detection, monitoring trends in endemic disease, evaluating interventions, and monitoring program performance and progress towards a predetermined control objective.

A surveillance system can be meaningful only if it provides information to make decisions concerning the nutrition requirements of the community, state or country. In addition to providing data for research and academic purposes, a food surveillance system helps governments safeguard the population’s nutritional requirements. It further provides key insights on the current situation and trends about the occurrence and spread of human pathogens in the food production chain.

Need for Food Surveillance

The immediate objectives of a food and nutrition surveillance system are:

  • To describe the population’s nutritional status, with particular reference to defined subgroups that are at risk. This permits the description of the character and magnitude of the nutrition problem and possible changes in these features.
  • To provide information that contributes to the analysis of causes and associated factors and therefore permits a selection of preventive measures, which may or may not be nutritional.
  • To promote decisions by governments concerning priorities and the disposal of resources to meet the needs of both “normal development” and emergencies.
  • To enable predictions to be made based on current trends to indicate the probable evolution of nutritional problems. Considered in conjunction with existing and potential measures and resources, these predictions will assist in the formulation of policy.
  • To monitor nutritional programs and to evaluate their effectiveness.

In emergency settings, the objectives specifically focus on:

  • A warning system – As a means of highlighting an evolving crisis.
  • Identification of appropriate response strategies. These may include non-food as well as food assistance to address the underlying causes of malnutrition.
  • Triggering a response – Nutrition surveillance systems provide a trend analysis focusing on the magnitude of change. This may trigger an in-depth assessment, which in turn may lead to a response.
  • Targeting – Nutrition information can help target more at-risk areas or in greater need of assistance.
  • Identification of malnourished children. Some forms of surveillance can identify acutely malnourished children.

Achieving Food Surveillance

The following are the main methods used for surveillance:

  1. Large-scale national surveys;
  2. Repeated small-scale surveys;
  3. Clinic-based monitoring;
  4. Sentinel site surveillance;
  5. School census data.

In an emergency setting, additional data can be obtained from:

  1. Rapid nutrition assessments;
  2. Rapid screening based on mid-upper arm circumference

Implementing Food Surveillance

This section highlights the steps to develop and implement a successful food surveillance system:

  1. Organization
  2. Setting an activity
  3. Practical steps to be undertaken.

The decision to establish a surveillance system must be based on clearly defined objectives, considering the availability of resources, staff capacity, sustainability, environmental factors, and capacity to respond to emerging nutritional and nutrition-related health problems. Once the decision has been made to establish a surveillance system, the first step is to establish a central nutrition surveillance unit, which will organize all the activities of the nutrition surveillance implementation processes.

The key objectives are generally to

  • Support food inspection activities
  • Ensure compliance with legal limits for microorganisms and chemical contaminants in food
  • Ensure foods comply with legal restrictions on the use of certain ingredients and processing technologies
  • Ensure the authenticity of certain foods
  • Provide data for risk assessment and risk management activities identify the pathogens found in foodstuffs for monitoring trends and establishing public health priorities for control and prevention strategies
  • Remove contaminated products from the market
  • Detect outbreaks and assist with their investigation.

Surveillance involves the sampling and testing of foods. This can be done in many ways.

  • Predominantly, food samples are taken by food law enforcement officers and sent to food control laboratories funded by the state.
  • Samples can be taken at the time of inspection of a food business or taken randomly at the retail or wholesale level.
  • Samples can also be taken on foot of a food complaint or to support an outbreak investigation.

Therefore, a food and nutrition surveillance system assists in enabling formulation, modification, and application of a country’s food and nutrition policies through accurate data. The system is used to create appropriate response strategies. Nutritional status is a recognized outcome of human well-being; therefore, it is possible to understand a vulnerable population’s evolving situation better by closely monitoring the indicators that measure nutritional status.


    1. pdf (fssai.gov.in)
    2. Food Surveillance Programme (cfs.gov.hk)
    3. https://www.google.com/url sa=i&url=https%3A%2F%2Fwww.securitymagazine.com%2Farticles%2F88993-how-surveillance-enables-better-food-processing-safety-compliance&psig=AOvVaw1ZoAd41PITxENY0bDvBmcs&ust=1619771512317000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCMiZsKCFo_ACFQAAAAAdAAAAABAD
    4. Food and nutrition monitoring in New Zealand. Wellington, New Zealand Ministry of Health, 2003 (Public Health Intelligence Occasional Bulletin, No. 19).
    5. Maire B et al. Nutritional surveillance: a sustainable operational approach. Antwerp, ITG Press, 2001. (Studies in Health Services Organisation & Policy, No. 19).
    6. Developing health management information systems: a practical guide for developing countries. Manila, World Health Organization Regional Office for the Western Pacific, 2004.
    7. Arnauld J, Alarcon JA, Immink MDC. Food security and food and nutrition surveillance in Central America: the need for functional approaches. Food and Nutrition Bulletin, 1990, 12:26–33.
    8. Definition of food security. Washington DC, United States Agency for International Development, 1992 (USAID Policy Determination, No. 19).
    9. The harmonized training package (HTP): resource material for training on nutrition in emergencies, Version 2. NutritionWorks, Emergency Nutrition Network, Inter-Agency Standing Committee Global Nutrition Cluster, 2011.
    10. https://www.google.com/url?sa=i&url=https%3A%2F%2Fbisouv.com%2Funcategorized%2F4239599%2Fglobal-food-safety-testing-and-technologies-market-2020-consumption-analysis-and-business-development-strategy-by-key-players-region-2025%2F&psig=AOvVaw1ZoAd41PITxENY0bDvBmcs&ust=1619771512317000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCMiZsKCFo_ACFQAAAAAdAAAAABAX

Processing of Condensed Milk- An Introduction

Condensed milk is obtained by removing roughly 60% of water from milk in a process called evaporation. These products have longer shelf life even when kept in unrefrigerated condition.

In this video lecture, Veena Mishra (Process Engineer at PMG) will introduce the Condensed Milk manufacturing process and key aspects, while she shall be also sharing the key Indian Standard Specification.

Retort technology- Operation and Working

Retort being the advanced preservation technique in food and beverage industry, involves heating of low acid foods, prone to microbial spoilage, hermetically sealed containers to extend their shelf life.

In this video lecture, Veena Mishra (Process Engineer) at PMG Engineering give you a brief about retort technology’s operation and working. In her previous presentation she had given a detailed introduction about retort technology and their types. You can check it out on PMG channel.

Retort Technology- An Introduction

Retort Technology plays an important role in the food preservation step. Retorts sterilize food after it is sealed in a container by steam or other heating methods. It provides safe, effective shelf stability and it can be done with fairly simple equipment.

In this video lecture, Veena Mishra (Process Engineer) at PMG Engineering introduces the Retort Technology and its importance, while highlighting this technique for milk preservation. She further talks about the various methods and typical equipment used for retorting in food industry.

Low GI Foods – “Step Up the Food Plate of Your Life”

What is GI?

The Glycemic Index (GI) is a measurement system that ranks foods according to their effect on your blood sugar levels. It was created in the early 1980s by Dr. David Jenkins, a Canadian professor. Pure glucose is used as a reference food and has a GI value of 100. Various foods are given GI value for the relative increase in blood sugar levels with respect to pure glucose. The three GI ratings are:

  • Low: 55 or fewer
  • Medium: 56–69
  • High: 70 or more

The table below provides examples of foods with low, medium, or high GI scores.

Below are six of the best low-GI food

Foods with a low GI value are the preferred choice for consumption. They are slowly digested and absorbed and cause a slower and smaller rise in blood sugar levels. On the other hand, foods with a high GI value should be consumed in limited amounts. They are quickly digested and absorbed, and result in a rapid rise and fall of blood sugar level

1. Oats – 55

With a GI score of 55, rolled porridge oats are low-GI breakfast cereal option. Oats contain beta-glucan, a type of fiber with several health benefits. Steel-cut and rolled oats have the best health benefits and the most favorable GI score. Quick and instant oats are more processed than steel-cut or rolled oats, and they have a higher GI score. Muesli that contains steel-cut or rolled oats can be a good option for people following a low-GI diet.

2. Milk – 37 to 39

A healthful addition to morning porridge, milk is a low-GI dairy product. The GI score for skimmed milk is 37, while full-fat milk has a score of 39.Milk is rich in calcium, which is important for bone health. Research suggests that drinking milk regularly may reduce the progression of knee osteoarthritis in women. Reduced-fat soy milk can have a GI score of between 17 and 44, and full-fat soy milk may score 44. The specific GI score will vary among brands.

3. Chickpeas – 28

Chickpeas, or garbanzo beans, are a low-GI legume, with a score of 28 on the scale. Chickpeas are a good source of protein and fiber, with 11.8 grams (g) and 10.6 g per cup, respectively. They also contain key nutrients, such as calcium, potassium, and vitamin B-9, which is sometimes called folate. People can use chickpeas as a substitute for potatoes or white rice, which have high GI scores. Roasted chickpeas make a quick and easy snack.

4. Carrots – 39

With a GI score of 39, carrots are a healthful alternative to bread for dipping into hummus. Carrots contain beta-carotene, which is good for eye health. They are also a great source of antioxidants, which help protect the body’s cells from damage. People can enjoy carrots boiled or steamed as a side vegetable with any dish.

5. Kidney beans – 24

With a GI score of 24, kidney beans are a versatile low-GI food. These beans are rich in protein and fiber, with 13.36 g and 11 g per cup, respectively. They also contain potassium and are very low in fat. Kidney beans make a great addition to meat-based or vegetarian chili.

6. Lentils – 32

Scoring 32 on the GI scale, lentils are a great low-GI addition to lunches and dinners. Lentils are rich in protein, with 17.86 g per cup, and fiber, with 15.6 g per cup. They are also a good source of phosphorus and potassium. An Indian dish called Dal is a wholesome and tasty way to enjoy lentils. Dal is also easy to make at home.

Many factors influence a food’s GI score, including:

  • Level of processing: More processed carbohydrates tend to have higher GI scores.
  • Ripeness: The sugar in fruit breaks down as the fruit ripens, increasing the GI score.
  • Preparation: The cooking process can break down carbohydrates, increasing the meal’s GI score.
  • Dressing: Using an acidic seasoning, such as lemon, lowers a meal’s GI score.
  • Type of starch: Amylose has a lower GI score than amylopectin.

People on a low-GI diet can also enjoy foods that do not contain carbohydrates, such as the following:

  1. Meat
  2. eggs
  3. fish
  4. seafood
  5. olive oil
  6. butter
  7. herbs
  8. spices
  9. nuts

Our body has an obligatory requirement for glucose dependent on metabolic demands of our body. It is usually 200 gm/day. Our brain completely depends upon oxygen and glucose. Maintaining a constant blood glucose level is important for our health and well-being. The scoring between 0 to 100 with glucose being the reference food with a GI food value fixed at 100. It is a new system of classifying carbohydrate containing foods, according to how quickly they raise the blood sugar levels in the body.

Reference –

  1. 8 principles of low-glycemic eating – Harvard Health
  2. Metabolic effects of low glycemic index diets (nih.gov)
  3. Sugars and Health Workshop: summary and conclusions | The American Journal of Clinical Nutrition | Oxford Academic (oup.com)
  4. The concept of low glycemic index and glycemic load foods as panacea for type 2 diabetes mellitus; prospects, challenges and solutions (nih.gov)
  5. https://cdn-prod.medicalnewstoday.com/content/images/articles/324/324871/low-glycemic-foods-lemon.jpg
  6. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.almased.com%2Fblog%2Fall-blogs%2Fdiabetes-health%2Fwhat-is-a-low-glycemic-high-protein-diet&psig=AOvVaw2EqRdG_gIp0ngk-jUbahPQ&ust=1618729504601000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCIjkjr_bhPACFQAAAAAdAAAAABAD

Wheat Milling Process – An Introduction

Wheat is one of the world’s most consumed cereal grains. It comes from a type of grass (Triticum) that is grown in countless varieties worldwide. Bread wheat, or common wheat, is the primary species. Several other closely related species include durum, spelt, emmer, einkorn, and Khorasan wheat. White and whole-wheat flour are key ingredients in baked goods, such as bread. Other wheat-based foods include pasta, noodles, semolina, bulgur, and couscous. Wheat is highly controversial because it contains a protein called gluten, which can trigger a harmful immune response in predisposed individuals. However, for people who tolerate it, whole-grain wheat can be a rich source of various antioxidants, vitamins, minerals, and fiber. Milling is the process by which cereal grains are ground into flour. The milling of Wheat consists in the separation of bran and germ from the endosperm and reduction of endosperm to fine flour. Various steps are involved in making the wheat flour.

The traditional procedure for milling wheat in India has been stone grinding to obtain whole wheat flour. This method results in 90-95% extraction rate flour which retains almost all the nutrients of the grain while simultaneously eliminating that part of the grain which is most indigestible like cellulose and phytic acid which binds and carries away minerals.

In modern milling, the wheat is subjected to cleaning to remove various types of impurities together with damaged kernels.

Following are the steps involved in wheat milling process-

  • Grain Cleaning / Vibrating Screen: Grain is removed of various types of impurities together with damaged, shrunken and broken kernels which are collectively known as screenings. This removes bits of straw and other coarse materials and second screen removes foreign materials like seeds.
  • Aspirator: It lifts off lighter impurities in the wheat. The stream of grain is directed across screens while air sucks off the dust and lighter.
  • Disc separator: After the aspirator it moves into a disc separator consisting of discs revolving on a horizontal axis. The surface of the discs indented to catch individual grains of wheat but reject larger of smaller material.
  • Scourer: The wheat then moves into the scourer, a machine in which beaters attached to a central shaft throw the wheat violently against the surrounding drum, buffing each kernel and breaking off the kernel hairs.
  • Magnetic Separator: The stream of wheat next passes over a magnetic separator that pulls out iron and steel particles contaminated during harvesting.

  • Washer stoner: high-speed rotators spin the wheat in the water bath. Excess water is thrown out by centrifugal force. Stones drop to the bottom and are removed. Lighter material float off leaving only the clean wheat.
  • Tempering: Wheat is tempered, before the start of grinding, the process in which moisture is added. Tempering aids in separation of the bran from the endosperm and helps to provide constant controlled amount of moisture and temperature throughout milling. The percentage of moisture, length of soaking, time and temperature are three important factors in tempering with different requirement in soft, medium and hard wheat.
  • Entoleter: Discs revolving at high speed in the scourer aspirator hurl the wheat against finger like pins. The impact cracks down any unsound kernel which is rejected.
  • Grinding bin: The “first break” rolls of a mill and are corrugated rather than smooth, break into coarse particles.
  • Sifter: The broken particles of wheat and bran go into a box like sifter where they are shaken through a series of cloth or screens to separate larger from the smaller particles. Larger particles are shaken off from the top by leaving the final flour to shift towards the bottom.
  • Purifier: The top fractions and particles of endosperm graded by size are carried to separate purifiers. In a purifier a controlled flow of air lifts off bran particles while cloth screen separates and grade coarse fractions by size and qualities.
  • The down purifier: Four or five additional break rolls with successively final corrugations and each followed by a sifter are usually used to rework the coarse stock from the sifter and reduce the wheat particles granular middling’s as free from bran as possible. Sifters, purifiers and rollers reduces wheat until the maximum amount of flour (72.0%) is separated.


Milling is a unit operation that transforms solid particles into smaller ones by applying forces such as shear, compression, friction, collision or impact. Milling processes can be used for making flour or for extracting gluten and starch (wet milling) from grains and cereals. In the food industry, raw materials, flours and intermediate products must often undergo milling or grinding for size reduction. Wheat is one of the cheapest and most nutritious crops. It is widely grown and is produced in abundance that is why it is used as staple food in most parts of India and the world. Clean, dry grains have to be milled to flour before further processing and consumption. The whole grain can be milled to leave just the endosperm for white flour. The products of this are bran and germ. The whole grain is a concentrated source of vitamins, minerals, and protein.

Reference –