The quality of a product is dependent on a number of factors. These factors include
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 (view image) 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 (view image) 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.
