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.

Programmable Logic Controller

PLC is an industrial grade computer used in automation industry to make system reliable through logic. It was invented by General motor, in America and Dick Morley was considered father of PLC. Dick Morley has identified the problem in industry that before PLC there is hardware wiring and this hardware nature made it difficult for design engineer to find troubleshooting and system is also not reliable. Now a days PLC is used in every automation industry and there are so many Industry providing automation digital solution like Schneider electric, Allen Bradley, Siemens industries and so on.

Working of PLC

PLC works in program of scan cycle where it read executes it program repeatedly and there is ladder logic and scan cycle consist of 3 steps.

  1. Read input
  2. Execute the program
  3. Write output

It follows the sequence of instruction and works in real time that is millisecond and in milliseconds for the processor to evaluate all the instruction and update all the output according to instruction.

Component of PLC

 They have three components, and these are: processor, power supply input/output section                               

  • Processor

It is brain of system of plc system, is a solid state device designed to perform a wide variety of production, machine tool and processor control function. Conventionally electromechanical device, relays and their associated wiring formerly performed these function. It operates in 5volt supply and supplied by power supply. Once the ladder diagram program is entered into processor, it remains until changed by the user with one of programming devices and program unaltered through power failure.

  • Power supply

It work is to convert line voltage into 24 dc voltage to provide internal circuitry. Basically, it is combination of transformer, rectifier and capacitor. In some cases, it also provides an isolated VDC supply to power dc input circuits, switches and indicators. There are so type power supply found in PLC like DC/DC converter power supply, Frequency converter plc power supply, Linear plc power supply and Switching plc power supply.

  • PLC Input/Output

Electrical noise like spike in power lines or load kick back would have series impact on PLC internal circuits this is where input/output portion play a very important role. The I/O both protect CPU from electrical noise. The I/O section is where status signal is filtered to remove noise level and CPU decision are made and put into operation. The PLC inputs provide their status to a storage area within the CPU AND outputs are driven from similar stored status in the CPU. Real world devices like push buttons, limit switches and sensor are connected through input modules in the PLC. These modules detect a change in state of input signal and provide a stored image to input element in ladder logic. The input element simulates action of relay contact within PLC. In turn, output element are energized which produces desired output signal to drive load such as motor controller, contactors, via output modules in the I/O.

  • PLC Programming

PLC are simply to program. They use a relay ladder language that is similar to magnetic relay circuitry. Engineers, and electrician can learn to program the PLC without extensive training or experience. There are numerous advantages in using PLC versus a relay or solid electronics. In a PLC, changes can be accomplished quickly and inmost cases, without hardware modification to the controller.


The advantages one gets with PLC are-

  1. Less wiring.
  2. Easier and make faster response in real time.
  3. It make trouble shooting easier and reducing downtime.
  4. High reliable and flexible.
  5. Low power consumption.
  6. Capable of handling complex logic.


PLC applications are typically customized system. It is low compared to cost specific custom- built control design. It requires less maintenance due to absence of moving parts, thus making things they work better. Overall, PLC appear to be an excellent solution for many different problems.





Earthing is arrangement by which an electrical installation is connected to means of earthing. This is usually for safety purposes although sometimes also for functional purposes, for example in case telegraph lines which use earth as conductor to save cost of return wire over a long circuit. If there is fault in electrical installation, a person could get an electric shock by touching a live metal part because electricity uses the body as path to earth. Earthing provides an alternate path for fault current to flow of earth. It can be seen in power system networks, industries, domestic homes, commercial buildings.  

In this below diagram, we can easily see that equipment body leakage current leakage from equipment body, pass to a human body as there is no grounding of equipment or device. This increases the risk of electrical shock. Hence earthing play an immense important role in industries, commercial building, home etc.

Electrical system without earthing

In this below diagram, with grounding of equipment, the whole leakage of current in equipment  body passes through low resistance path called ground wire so there is a negligible chance of electrical shock.                      

Electrical system with earthing


Method of earthing

There are various types of earthing is done like rod earthing, strip earthing, plate earthing, pipe earthing and earthing through water mains but pipe and plate earthing is preferred so much.

  • Earthing mat

 It is done by number of joining of rod through copper conductor and it reduces overall grounding resistance of system. Such type of earthing helps to limiting the potential. This type of earthing used in where there is a high fault current is to be experienced. While designing this system following points must consider.

  • Earthing electrode

 In this earthing, we may use wire, rod, pipe and inserted vertically or horizontally into ground and In distribution system there is rod of nearly 1m is used and inserted vertically into ground but in generating substations there is earthing mat is used rather than Earthing electrode.

  • Pipe earthing

This type of earthing is mostly used and this is considered best method as compared to other type of earthing for same soil condition. In this earthing, the galvanized steel or perforated pipe of approved length and diameter depend upon types of soil and current carried by that rod is placed upright in wet soil as shown in figure. Normally size of pipe is of 40mm diameter and 2.5m in length for ordinary soil but for dry soil length may increase. When there is summer then moisture of soil decrease which cause increase in ground resistance some arrangement of water is done for water accessible or 3 or 4 buckets of water is put into a pipe which is connected to soil pit. In soil pit, there is mixed of charcoal and salt around the pipe to reduce the effective resistance of soil.

  • Plate earthing

In this earthing, either copper plate of 60cm×60cm×3m or galvanized iron rod of 60 cm× 60 cm×6mm is buried in ground with it face vertically to ground and depth is not less than 3m from ground level. The ground wire connected to copper plate through nut or bolt. Copper wire is not used mostly because of high costing. The layer of soil and coke is placed in soil pit.

  • Earthing through water mains

In this type of grounding, the copper or GI wire is connected to water mains through water pipe and water pipe is directly connected to earth as shown in fig. when the fault condition occurs the whole leakage current passes through water steel pipe and earthed.                     





Vacuum Circuit Breaker

The vacuum interrupter technology was first introduced in the year of 1960 but still is a developing technology.  A circuit breaker is a device that interrupts an electric circuit to prevent unwarranted current caused by short circuit, typically resulting from overload. It’s basically functionality is to interrupt current flow after a fault is deducted. This is kind of circuit breaker where arc quenching takes place in a vacuum medium. The operation of switching on and closing of current carrying contacts and interrelated arc interruption takes place in vacuum chamber in a breaker is called vacuum interrupter. Vacuum offers high insulating strength.

  1. Construction

The vacuum circuit breaker consists of fixed contact, moving contact and an arc shield mounted in a vacuum interrupter. The outer insulating body is made with glass and has high vacuum capacity. The movable part is connected to control mechanism by stainless steel bellows. Arc shield prevents deterioration of internal dielectric strength by preventing metallic vapors from falling on inside surface of outer insulating body. To reduce possibility of leak, permanent or tight sealing is done. Vacuum has high dielectric strength as compared to air so vacuum circuit breaker is preferred where arc interruption need high in place of air circuit breaker.

  1. Working principle

When breaker operates, the moving contact separates from fixed contact and an arc is struck between the contacts. The production of arc is due to ionization of metals ions and depend very much upon materials of contact. The arc is quickly extinguished because metallic vapours, electrons, and ions produced during arc are diffused in a short time and seized by surface of moving and fixed member and shields. Since vacuum has very fast rate of recovery of dielectric strength because dielectric strength of vacuum is eight times greater than air and four times greater than sf6.

Contact materials must have following properties:

  • High density.
  • Contact resistance must be less.
  • High arc resist capability.
  • A boiling point must be high to diminish arc erosion.
  • Thermal conductivity is high to dissipate quickly the large heat produced throughout arcing 
  1. Ratings and specification of vacuum circuit breaker

The rating of circuits breakers is generally given in MVA. VCB comes a wide variety ranging from 250 to 1500MVA. According to European standard, the commonly available preferred values for rated current are 25A, 32A, 40A, 50A, 63A, 80A, 100A, 125A

  1. Advantages
  • It does not require any additional filling of oil or gas.
  • The VCB is fast in operation so ideal for fault clearing and suitable for repeated operation comfortably
  • Vacuum circuit breaker is almost maintenance free and minimum maintenance required as compared to other circuit breakers.
  • No exhaust of gas to atmosphere and noiseless operation.
  • No fire hazards
  • The dielectric strength of vacuum is greater than air and sf6 circuit breaker. High dielectric strength makes possible to quench a vacuum arc within very small gap.
  1. Disadvantages 

  • The main disadvantages of this circuit breaker is that it become uneconomical at voltage exceeding 38kv because at more than 38kv, two number of vacuum circuit breaker are required to be connected in series.
  • VCB production is uneconomical if produced in small quantities.
  1. Conclusion

Now a days, vacuum circuit breakers applications to not only medium voltage power systems but also for in high voltage transmission systems. It is because it has so many advantages characteristics such as high interruption capability, long operation life, safety and high-cost performance. After Kyoto protocol in 1997, sf6 circuit breaker is one of major problem of global warming gases, since then vacuum circuit breaker uses become widespread.

  1. Reference




It is static device used to step up and step down of voltage level without change in frequency and power. Transformer works on the mutual induction principle. This principle states that when electric current flows in primary winding supply then due to alternating nature of supply voltage, it develops varying nature of flux and whenever varying mutual flux linked to a secondary winding through core then according to faraday law, whenever either conductor cuts a magnetic flux or magnetic flux cuts a conductor, EMF produced in conductor, hence in this way, EMF developed on secondary winding.

The basic phenomenon behind working of transformer is mutual induction between two winding linked by a common magnetic flux. Transformer consist of two inductive coils, LV and HV winding. These windings are electrically separated but magnetically linked to each other. When LV or HV winding are supplied of ac supply then alternating magnetic flux developed in the winding and it get linked to load side by a common path that phenomenon is called mutual induction. Due to this, alternating EMF is produced in load side whenever circuit will be closed the current flows in load side.

  1. Types of Transformer

According to change in level of voltage, there are two type of transformer –

1.1.  Step up transformer

1.2.  Step down transformer

  • Step up transformer

 It is used to step up the level of voltage. This transformer increases voltage from primary to secondary winding. In this transformer, secondary turns are more than primary turns. This transformer has made long distance transmission power practical because it steps up the voltage and corresponding it decrease current at same ratio hence, due to decreases the current level there is much less power losses in line. This is used generally for long distribution.

  • Step down transformer

This transformer decreases level of voltage from primary to secondary. In this transformer, secondary turns are less than primary turns. It is used mainly in distribution and load side. This transformer has a wide variety of application like distribution side and electronic devices etc. When it comes to operating voltage, the step up transformer application can be roughly divided into two groups: LV (voltages up to 1kv) and HV (voltages above 1kv). 

  1. Construction of transformer

The construction of transformer is of iron core laminated with steel bands core lamination are constructed from insulated metal thin metal strips. These laminations are separated and wound around the limp using a sheet of coat. The laminations are separated and wound around the limb using a sheet of coat or parchment. The winding consists of two types, main and secondary winding. These winding are isolated from each other and are made by electrical coil.

  • Core

The core of transformer is typically built with high permeability materials, such as silicon steel laminations. Based upon configuration of main and secondary windings, a transformer core may be formed in two ways.

  • Core type construction

In core type construction, as shown in fig, the coils are wound around two limb of rectangular magnetic core. Each limb carries one half of primary winding and one half of secondary winding so as to reduce leakage reactance to minimum possible. The LV is wound on inside nearer to core while the HV winding wound on inside nearer to core while HV winding is wound over LV winding away from the core in order to reduce amount of insulation material required. 

  • Shell type construction

In shell type construction, the coils are wound on central limb of a three limb core. The entire flux passes through central limb and divides in two parts going to side limbs shown in fig. Sandwich type winding is used in such a construction. This type of construction is popular in low voltage application like transformer used in electronic devices, power electronics converters.                                     



                                                      Fig: Shell and core type construction

  • Conservator

A cylindrical tank plays a key role in transformer. It is arranged over the main tank roof so that sufficient space can be provided to expand to transformer oil. Once the temperature increases, then oil volume can also be increases, then oil volume can also be increased. Then oil goes to conservator tank after cooling down it returns to main tank. The shape of conservator tank in transformer is cylindrical where both ends of oil container are closed. One side of the container is provided for cleaning purpose.



                                                    Fig: Conservator tank

  • Breather

 As a temperature of transformer increases, the insulating oil in transformer heats up.   When oil heats up and spreads, the transformer breathes air in and oil is cooled down and oil level is consumed. The oil level in chamber rises and reduces as breather brings the air in and out to cool the air. The air carries moisture, which contaminates oil and thus deteriorates the consistency of oil. The breather is packed with silica gel to remove moisture content. The key feature of silica gel is to isolate moisture from oil while preserving the consistency of insulating oil. The color of silica gel becomes pink as it absorbs moisture from oil

                                                                 Fig: Breather


  • Radiator

The basic function of radiator is to cool down the transformer oil. Oil immersed power transformer is generally provided with detachable pressed sheet radiator with isolating valves. But in case of small size distributing transformer, the radiators are generally integrated parts of transformer body and projected from main tank. The working principle of radiator is very simple. It just increases the surface area for dissipating heat of oil. Under loaded condition, warm oil increases in volume and enter into upper portion of main tank. Then oil enters in radiator through top valve and cools down by dissipating heat through thin radiator wall. This cold oil comes back to main tank through bottom radiator valve.

  • Bushings

Bushings are the insulation system in construction of transformer that enables an electrical conductor to safely transfer electrical energy through it. When a significant volume of electrical energy travel through it, it provides electrical field power to withstand insulation of conductor. In small transformer, solid porcelain type bushing   is used, and in large transformer, oil filled condense type bushing is used.

                                                                 Fig: Bushing


  • Buchholz relay

In order to protect of transformer from internal short circuit due to oil, buchholz relay is used for oil immersed transformer, buchholz relay is an oil and gas actuated relay which sense the fault occurring in the part immersed in transformer. Whenever short circuit occurs in transformer then oil generates enough heat and become decompose itself into hydrogen and monoxide gases and these gases travel through pipe and relay is also mounted on pipe between main tank and conservator tank and these relay sense the gas and activate the tripping circuit.

                                                            Fig: Buchholz                                                              

  1. Distribution voltages classes and standard ratings of transformer

Transformer are used wide variety of purposes, with complete range of voltage and power ratings as well as many special features for particular applications.

The following cover main types:

  • Small transformer

They are used for stationary, portable or hand held power supply units. They may be used to supply three phase power up to 40kva at frequencies up to 1mhz. 

  • Distribution Transformer

 They are used to distribute power to domestic premises. They may be single phase or three phase. They have rating ranging from16kva up to 2500kva and this type of transformer like 11, 6.6, 3.3, 440 sand 230V. 

  •  Supply Transformer 

They are used to supply larger industrial premises or distribution substations. Ratings ranging from 4mva to 30mva, with primary winding rated up to 66kv and secondary up to 36kv. The primary winding has a highest voltage ranging from 3.6kv to 36kv, the secondary winding voltage does not exceed 1.1kv. 

  • Transmission transformer

          They are among largest and highest voltage transformer in use. They are used to transmit power between high voltage networks and Rating ranging from 60mva to 1000mva and winding are rated at 33, 66,132, 275 and 400kv.       

  •  Power or step up transformer 

Power is usually generated in large power station at typically 11kv-20kv, and this transformer are used to step up voltage. These transformers are usually rated at 400, 500, 630,800 or 1000mva and transmit power at 66, 110,132,220, 400 and 765kv. 

  1. References 


Lightning Protection Unit

Lightning is an atmospheric discharge of electricity from thunder, occurs during thunderstorms. The atmospheric discharge lightning can travel at speed of light and its temperature can reach up to 30,000 degree Celsius. The effect of lightning strike may cause thousands of death every year. It is a natural phenomenon occurring at any day and this discharge produce a wide range of electromagnetic radiation.

Lightning protection unit are designed to protect the building structures, industrial appliances, commercial building, HT substation, electrical equipments, communication transmission lines  etc. from damage effect of lightning strike. It play a very important role in safety from lightning storms. A lightning strike could bring thousands of mega ampere current within milliseconds. As a result, failure of home and industrial appliances, fire in building structures, home etc. and may cause death also.

                                       Fig: Effect of lightning strike on building

                                         Fig: Building with lightning protection unit


As we can relate with both of the figure above , effect of lightning on building without and with light protection unit.

  1. Components of lightning protection devices

    • Air terminal

Air terminal is used to intercept lightning strike. It provide a low resistance path to lightning strike and it is connected to down conductor and down conductor is connected with earthing electrode which is directly kept into soil mud. Whenever lightning strike hits, the whole current is discharged through air terminal- which is  connected to ground electrode instead of building structure.      

  • Down conductor

Down conductor provide a low resistive path to lightning current from air terminal to ground electrode. It should be installed vertically and straight to avoid the bending of down conductor. This shall ensure minimum inductance because of resistance in the path of discharging current and surges.

  •     Grounding

 It play a very important role in discharging lightning current. It dissipates all the lightning current into a big mass of soil. The soil resistivity should be less than 10 ohm for comfortable discharge of current, according to electrical standard. A typically earth electrode of copper alloy is deep driven vertically into the soil. Soil have finit conductivity so that current discharges easily. The mixing of charcoal and salt is done in soil pit to decrease the resistivity of soil.

  1. Lightning Arrestor

These devices are designed to protect the transmission line, insulations, switchgears, transformers communication line by the effect of lightning strike. They directly installed to power substation , distribution system or telecommunication line. It has ground termininal and high voltage terminal and whenever lightning travel along the power line to arrestor then current through surges diverted by arrestor to earth. In telegraphy and telecommunication, it is placed where wires enter a structure so that preventing damage to electronic instrument and ensuring safety near to them. Their purpose is basically to limit the rise in voltage when power lines are struck by lightning.


                                                  Fig: Lightning arrestors

Small version of light arrestor is called surge arrestor. That are generally used for protection from surges produced in transient condition and they are not used directly to protect from lightning. The most common surge arrestor is non linear metal oxide resistor type in porcelain or silicon rubber housing that are fitted parallel to circuit and connected to earth griding.

 Types of Lightening Arrestors 

  • Station class

Typically used in power stations or substations  and other high voltages structure and areas. It is designed to protect equipment above 20MVA range. 

  • Intermediate class

Designed to used in medium voltage equuipment areas, electrical substaions, transformer or other substation equipment and it is designed in range of 1 to 20 MVA.

  • Distribution class

Most commonly found on transformers and are commonly used in equipments rated at 1000kva or less.

  • Secondary class

Found in homes and commercial buildings and provide  least amount of protection to electrical system.

  1. Conclusion

All electrical equipment in an electrical system needs to be protected from voltage surges. The rating of arrestor, the class of arrestor and location of arrestor all play a important role in the surge protection. In protection of substation, we use different class of lightning arrestors to protect the electrical equipment and In ships, water is used to discharge voltage.

  1. References


Flooring In Food Industry

Flooring is the general term for a permanent covering of a floor, or for the work of installing such a floor covering. The food industry is one of the most challenging ones when it comes to the field of flooring. Many factors are to be considered in the selection of flooring materials and their finish. Floors in food manufacturing or food preparation premises must be able to be cleaned effectively and thoroughly, must not absorb grease, food substances, or water, harbor pests or bacteria, and should be laid to a safe design so as not to cause the pooling or ponding of the water. Different grades of flooring are needed for the different areas found within the food environment. For example, production areas often need a hard-wearing, chemical-resistant floor finish, which can stand up to heavy machinery and general wear and tear.

Pre-requisite for flooring

The floor finish has several different functions in a factory. The main parameters to be considered in the selection of flooring material is: 

  1. Hygienic and easy to clean surface

As part of its HACCP quality system, a producer must assure himself that a floor will not compromise food safety. The easiest way to do this is to use a flooring system that has appropriate third-party certification for use in food handling facilities. Also, a floor should be dense, impervious, and with bacterial cleanability comparable to stainless steel

  1. Safe working environment

The floor must provide a safe working environment for operatives so it must have an appropriate level of slip resistance. The correct level of slip resistance, for any given area, will depend upon activities taking place. 

  1. Durability

Durability comes from a combination of physical and chemical properties. It requires resistance to chemicals and thermal shock, as well as mechanical abrasion and impact.

Floor Zoning

A zoning plan on the surface of the floor is a good idea if a food plant has identified any areas at risk of cross-contamination or other hazards and is looking to segregate areas or zones by different processes or procedures or to designate different levels of hygiene through a simple color-coded system.

Although there is no universal system or language in place, pigmented flooring materials can be used to designate walkways or hazard risks in line with individual company policies and practices. The zoning helps to identify the high-risk and low-risk areas. Sensitive wet and dry processing areas need floors that deliver the ultimate in hygiene performance. In these environments, steam cleanable products are often sought. For sensitive areas, such as tray washrooms, antimicrobial floors are often chosen.

Flooring Options

There are many different food processing floor options available in the marketplace.  Epoxy and urethane systems are readily available.  However, cementitious urethane floors are considered the modern, high-performance, standard for food and beverage safe flooring in processing facilities. The ceramic tiles, Dairy tiles, and hard non-reactive stones were the most used ones in the previous decades. 

The flooring options can be classified into two main categories Tiles/Stones, and floor coatings.

  1. Tiles/ Stones

When looking at food processing floor options, dairy brick, and quarry tile quickly come to mind.  These are products that have widely been used in the food processing industry.  At one time, these products were the only systems available (before the advent of seamless polymeric floors).  These systems are only a viable choice for new construction or long production shutdowns.  Drawbacks include the added thickness of these systems, along with a prolonged installation duration.  These issues make brick and tile difficult or impossible for renovation and fast turnaround projects.

Mandanna Stone Tiles are the most commonly used tiles in the dairy industry in India. Mandana Sandstone is a chocolate-colored sandstone with colors ranging from dark red-brown to plum. This is hard-wearing & frost-resistant sandstone.

  1. Floor Coatings

Floor coatings are tough, protective layers used in applications where heavy surface wear or corrosion is expected. Food processing plant flooring options are different types of coating, which go onto something like concrete flooring.

  • Epoxy Coatings

There are numerous types of food-grade epoxy flooring available in the market. They are a fantastic option and are incredibly durable, with many benefits. They can withstand exposure to agents like acids and alkalis, which have the potential to damage other kinds of flooring.

There is also the option to include additives—like anti-skid additives—to the epoxy mix to create an even better product. Certain types of food-safe epoxy coating options, like novolacs, also offer greater chemical and heat resistance. Epoxy coatings cure quickly, which means less downtime within the facility, unlike other options on the market. Epoxy coatings are also a visually appealing option, with the ability to add aggregates like quartz or marble into the mixture.

  • Urethane Coatings

A polyurethane coating (or urethane floor coating), is a highly flexible, highly abrasion-resistant floor coating that is known for its shine and longevity. These can have a more considerable upfront cost but will last much longer than other flooring options.

Additives in the urethane mixture provide these floors with superior resistance to thermal cycling, which helps add to its long-lasting nature. This helps to make them a popular choice in food processing plants that work with meat and poultry products+++. Like epoxies, urethane can have decorative touches added to it to make the flooring more visually appealing.

  • Methyl Methacrylate(MMA) Coatings

Methyl methacrylate (MMA) systems offer food manufacturing and processing environments certain performance advantages compared to alternative resin materials, most notably their ability to cure at an incredible speed and be installed at extremely low temperatures.

MMA resin can fully cure in just one to two hours, making it an ideal choice for operational facilities looking to minimize downtime and disruption as well as fast-track new-build construction projects. MMA resin material demonstrates a high level of resistance to a range of acids and alkalis. Although MMAs have a unique odour during installation, the odour is harmless and can be minimised during installation with proper ventilation.

  • Poly Ureas Coatings

For a flooring option that does well in demanding environments, there are polyureas coatings. These coatings are impact resistant. They are the quickest to cure and give off virtually no odor. Because polyureas coatings are flexible flooring, they are also better able to withstand extreme temperatures found in various facilities.

Cleaning and Maintenance

An effective cleaning and maintenance routine should be in place to preserve the aesthetic and performance of the floor finish but more importantly to reduce the risk of microbial contamination. Between wash cycles, resin-based flooring materials should, where possible, be maintained in a dry state and at low relative humidity conditions.

Flooring must be sloped at around 1.5-2% to allow water to drain correctly. Resin flooring will not be affected by most special-purpose cleaning materials when these are used in accordance with the Chemical Cleaning Manufacturers’ instructions. Specific cleaning instructions should also be sought from the resin flooring manufacturer.

With so many options to choose from, selecting a fit-for-purpose flooring solution that can withstand the operational demands of food manufacturing, processing, and packaging environments can be challenging. On top of this, stringent health, safety, and hygiene standards, as well as budget constraints, must be considered.




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.




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 (
    2. Food Surveillance Programme (
    3. sa=i&
    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.