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Quality control procedures and equipment.
The quality of a product is dependent on a number of factors. These factors include the quality of ingredients used to make the product, cooking time and / or temperature used during processing, the cleanliness of processing premises, processing equipment and the standards of hygiene practiced by persons making the product.
Utilising poor quality ingredients will produce a poor quality end product. It is important to adopt practices of checking the quality of raw materials and ingredients used for making end products. For example, oil used for frying chips should be fresh or if it has been used for frying before, it should not be dark brown in colour nor have a strong smell. The flesh of cassava tubers used for making flour should not be blue / black in colour otherwise the final product will also have a blue / black colour. The quality of water used in processing premises ( including water used for washing equipment and utensils) should be clean and safe.
For products preserved by the use of heat to kill the spoilage and pathogenic micro - organisms, it is essential that both the time and temperature used for processing are adequate to kill the spoilage micro - organisms. It is not enough to just heat the product to very high temperatures since too high a temperature will change the taste and nutritional content of the food. Cooking temperatures can be monitored with the use of thermometers. For foods use, common, glass bulb, mercury thermometers should not be used incase they crack and the mercury contaminates the food product. For commercial operations, digital probe type thermometers are available. These thermometers are easy to use and have different types of probes for monitoring temperatures ovens, refrigerators and the product itself ( rod type probe ) or for monitoring the temperature of oil used for deep frying chips ( high temperature resistant wires). Manufacturers of these thermometers provide comprehensive instructions on how to use these instruments.
For products preserved by the use of preservative agents, the strength of the preservative has to be strong enough to suppress the growth or destroy the spoilage micro - organisms in the product. In jam making, sugar prevents the growth of micro - organisms. The sugar dissolved in the product, reduces the amount of water available for spoilage micro - organisms to grow. When making jam commercially, it is important to check that each batch of jam contains enough sugar to prevent the growth of spoilage micro - organisms. Refractometers ( illustrated on page 37 ) are used for checking the sugar content of each batch of jam. The instrument is able to determine the percentage of sugar dissolved in the jam. Full instructions on the use of such an instrument are provided by the manufacturers. Should such an instrument be purchased then the assistance of a food technologist or trained laboratory technician should be sought to' make sure it is being used correctly.
Adopting goods standards of cleanliness of processing premises, processing equipment / utensils and standards of hygiene practiced by persons making the product are important for the quality and safety of the final product.
The interior and exterior of processing premises ( whether the kitchen of a domestic house or a purpose built processing building ) should be in a good state of repair. Holes in window screening, gaps under doorways, open spaces in the roof provide insect and vermin with easy entry points. All rubbish and waste material should be kept well away from food processing premises to discourage the congregation of flies and other insects. Proper disposal of rubbish also important for maintaining the cleanliness of areas surrounding food processing premises.
Internally all working areas and surfaces should be regularly cleaned with sanitising agents ( mild bleach, disinfectants or if available steam ). It is useful to draw up a schedule for cleaning areas that are not used every day ( such as store rooms, ceiling areas, ceiling fans and areas behind processing equipment ). The advice of a qualified food technologist should be sought concerning the most suitable chemicals and cleaning agents for cleaning equipment and work surfaces which are to be in direct contact with food materials. Processing equipment and cooking utensils should be thoroughly cleaned after use and stored in a clean environment. As many metal items of equipment and kitchen utensils sold in local shops are not made from stainless steel, they should be thoroughly dried after cleaning and regularly inspected for signs of rust. If using oil to lubricate mechanical items of equipment, then ensure they do not come into contact with the food materials and ingredients during processing operations.
People involved in both cleaning and processing operations should keep themselves clean and tidy. Outdoor clothing and shoes should be changed before entering the food processing premises. Clean aprons should be used and long hair tied up to prevent contaminating the food product with hair. This helps maintain a clean working environment within the kitchen or processing premises. It is extremely important to wash the hands ( with soap ) and thoroughly dried ( using clean towels ) before handling any food material. Hands should be re - washed every time the processor leaves the processing area to visit the toilet, answer the telephone or be called away for any other reason.
When products are produced for sale outside the home, samples of each batch of product made should be retained and visually inspected over a period of time. Should any signs of deterioration be found ( such as mould development on the surface of jam, increase in moisture content of stored flour ), then corrective measures need to be taken. The advice of a qualified food technologist should be sought to solve the problem.
Processed products should be stored in suitable conditions ( ice - cream obviously needs to be kept in a freezer). It is fine to keep chips in sealed plastic bags in a store room provided that both the packaging material keeps out moisture and that the store room is clean, dry, cool and free from insect or rodent infestation. Note that a " store " could even refer to a cupboard used in a domestic kitchen. Even a cupboard must be kept clean and dry when used for storing food.
Packaging materials and product labelling.
A good quality product should also be packaged and presented well. Packaging materials protect processed products during storage.
Packaging materials used should be strong enough to withstand the type of handling the product will be exposed to and act as a barrier against moisture, oxygen and unwanted matter entering the product. The type of packaging material chosen should however be relatively inexpensive and where possible purchased locally. The package must also be sealed well in order to prevent oxygen, moisture and other unwanted material from entering the product and reducing the storage life of the product.
When using glass jars for preserving root crops as jam the following issues should be noted. Only glass jars which are intact should be used. Glass jars should be inspected for cracks. Jars with cracks ( no matter how fine ), especially around the neck of the jar, should be discarded. Cracks along the neck of the jars prevent a good air tight seal forming when the lid is screwed on. All jars and lids should be sterilised prior to use [ see jam recipe for details of how to sterilise the jars ].
There are many forms of plastic packaging materials. Different types of plastic are suited to different packaging requirements - that is some are moisture proof or do not allow gases to enter the product ( or both ). The most commonly used plastic films are; polyethylene ( polythene ) and polyvinyl chloride ( PVC ). Polythene is milky white in colour and slightly greasy to touch. It is highly permeable to oxygen and carbon dioxide and slightly absorbs oils, grease and organic liquid vapours. The advantages of polythene are that it has a low permeability to water at normal temperatures and is low in cost. PVC is the strongest and most barrier proof plastic of those mentioned above. It is a transparent, strong plastic. If using PVC for food use, then it should have been made using non - toxic plasticisers or be lead free unplasticised PVC. Cellulose film is also widely used in food packaging but it is very permeable to water vapour and is not very strong. and cannot be subjected to heat sealing. Cellulose film is usually used for wrapping rather than packaging foods.
In order to seal plastic bags, heat needs to be applied. Sealing plastic bags with an elastic band does not provide an adequate seal to keep out moisture. There are specially designed plastic bag sealers available on the market. A sketch of a typical model is illustrated on page 39. Plastic bags can be heat sealed using a wax candle and hacksaw blade. However, this method is not recommended for use on a commercial scale operation but could be used to seal plastic bags at the household level.
After packaging it is important to clearly label the packages. Products must be clearly labelled with all necessary information. Appropriate Government authorities should be approached concerning information which has to be presented on product labels by law. There may also be legal requirements regarding the designs of labels used. This type of information is usually available from either the Ministry of Health, Ministry of Trade and Commerce or Ministry of Agriculture. Whether labelling products for domestic or commercial use, labels should always state basic information such as the name of the product and date of manufacture. For commercial operations, the name of the manufacturer, gross or net weights of product per unit ( that is weight of chips in one bag, weight of jam in one jar ) and a list of the ingredients used in making the product should also be presented. Labels can be hand written as long as the information is written in very clear print and permanent ink is used. The use of adhesive labels on the outside of the package is advised. Placing labels inside a clear, plastic bag is not advised.
Candle and hacksaw blade method of sealing plastic bags
To seal plastic bags using this method you will require a wax candle, hacksaw blade or flat piece of thin metal and matches.
Light the candle. Fold the edge of the plastic bag over the teeth of the hack-saw blade. Lightly pass the folded edge of plastic through the candle flame. Remove the hacksaw blade and check that the seam is well sealed.
Candle and hacksaw blade method of sealing plastic bags.
