7.4.3 Good Manufacturing Practices for Tropical Roots and Tubers
A good manufacturing practice (GMPs) is a part of QA that ensures consistent quality production of the produces as per the standards and requirements of the marketing authorizations or product specification. GMP is aimed primarily at diminishing the risks inherent in food production. Such risks are essentially of two types:
1. man and machine contamination; and
2. environmental and pest contamination.
Therefore, to prevent contamination, the basic requirements of GMP are considered, which are presented in Table 7.2.
Table 7.2 Basic requirements of GMP
S. no. | Basic requirements of GMP
1 | Clearly defined manufacturing practices
2 | Clearly defined and systematically reviewed processes
3 | Proper performance of qualification and validation
4 | Proper prov'sion of appropriate resources
5 | Trained and qualified personnel
6 | Premises, space, equipment and servces
7 | Materials, containers and labels
8 | Storage and transport
9 | Laboratories and in-process control
10 | Clear, written instructions and procedures
11 | Trained operators
12 | Records of actions, deviations and investigation
13 | Records for manufacture and distribution
14 | Proper storage and distribution
15 | Systems for complaints and recalls
Good Practices in Production:
(a) Pest Control Plan: Rodents and insects are the main pests, which would be problematic in root and tuber processing plants, therefore it is essential to preserve a non-attractive environment in a documented plan, where tidying and cleaning of technical buildings is done routinely so as not to support rodent settlement.
The plan should include the secluded storage of unused materials and machines. Externally, there should be no holes and spaces on idle land. The vegetation and the grass in the lawns should be taken care of and shortened routinely. There should not be papers, plastic film and other debris dumped on the land, as these could serve as a protective structure for rodents. An active control and pest detection plan needs to be in place.
(b) Water Quality: Water is crucial in the processing of roots and tubers, because it is used in different unit operations. It is thus necessary that sufficient potable water be available in the production areas. Water quality is fundamentally judged by its physical, chemical, microbiological and sensory characteristics.
The quality of water can deteriorate due to inadequacy of treatment plants, direct discharge of untreated sewage into rivers, in addition to inefficient management of piped water distribution systems (UNEP, 2001). In many low-income countries, growing agricultural activities, urbanization and industrialization lead to ever-increasing contamination of streams, rivers, lakes and reservoirs, which are usually the main sources of drinking water (Amajor et al., 2012).
Water used in processing is thus likely to be infected and should be intermittently tested for contamination. The quality of the water should be controlled through regular analyses, which are then weighed against conventional standards. The chemical analysis of water entails assessment of Ca2+ Mg2+, CO32-and SO42-, total hardness as well as minor ions such as Fe2+ Fe3+ NO3 and NH3(nitrate and ammonia) and nitrogen (Amajor et al., 2012). The different quality standards for drinking water are given in Table 7.3.
Table 7.3 Different water quality standards
S. no | Parameter | WHO guideline values (Maximum limit)
1 | Appearance and taste | Should be acceptable
2 | Colour | 15 TCU
3 | Turbidity | 5 NTU
4 | Total dissolved solids | 1000 mg/l
5 | pH | 6.5–8.5
6 | Total hardness | 500 mg/l
7 | Sodium | 200 mg/l
8 | Potassium | 30 mg/l
9 | Calcium | 200 mg/l
10 | Magnesium | 150 mg/l
11 | Sulphate | 250 mg/l
12 | Nitrate | 50 mg/l
13 | E. coli | 0 coliforms/100 ml
14 | Total coliform bacteria | 0 coliforms/100 ml
TCU: True colour units;NTU: Nephelometric turbidity unit
Source: FAO (2006), WHO (2006)
(c) Microbiological Safety: Microbiological safety hazards are the root of the majority of food-borne illnesses and include pathogenic bacteria, viruses and parasites. The microbial safety is assessed on the basis of hazard identification and characterization, exposure assessment and risk characterization. Bacillus spp., Lactobacillus spp., Geotrichum spp. and Aspergillus spp. can be the potential biological hazard, besides several others, in the processing of roots and tubers, especially cassava.
Some of the problems that lead to the contamination of the products can easily be resolved with effective hygienic practices. Employee hygiene is thus of importance to the sanitation of plants and it is one of the main causes of contamination of food (Higgins, 2000). Risk analysis provides a logical and clear procedure for estimating risks, assembly of information, drawing conclusions and communicating information to reach decisions. If a risk analysis is carried out, bacteriological tests on the root and tuber produced at different manufacturing stages, enables the assessment of the effect of each processing stage to reduce or increase risk.
(d) Chemical Safety: Chemical hazards, particularly those that can be closely controlled in the food supply such as food additives, residues of crop pesticides and veterinary drugs, should conventionally been subjected to a “zero risk approach”. Other chemical hazards may also include unintentionally added chemicals (e.g. cleaning agents, solvents) and toxins (e.g. histamine in fish, mycotoxins).
(e) Physical Safety: Physical hazard is an extraneous object/foreign matter in food that can cause injury or illness in the person after consuming the product. Rocks, wood, metal, and certain other objects are sometimes found in raw ingredients. In addition, physical hazards can occur during transport, processing and distribution of foods due to equipment failure or laxity.
Extraneous substances which can arise during the processing of R (roots) and T (tubers) produce could consist of nails from boxes, machinery parts and small instruments. Separation devices/equipment should be used to separate the foreign matter from the product and the detection schemes may include metal detectors, X-ray machines, optical systems, etc.
Processing Operations Before any processing operation is started, steps should be taken to ensure that the work area and equipment are clean and free from any starting materials, products and residues. Any necessary in-process controls and environmental controls should be carried out and recorded. Measuring, weighing, recording and control equipment and instruments should be serviced and calibrated at pre-specified intervals. Repair and maintenance operations should not present any hazard to the quality of the products.
Packaging and Labelling Packing materials in direct contact with the products should not have any adverse effect on the quality. Mistakes may occur during packaging and labelling and so to make possible traceability, each product needs to be assigned a batch or lot number. Traceability, in this framework, necessitates that all steps in the root and tuber procedures be checked, wherever possible, by reference to documented results, calibrations, standards and calculations. Depending on the properties of the product and shelf life, the packaging materials may be selected. All finished root and tuber products should be identified by labelling, as required by the national legislation, bearing at least the following information (Table 7.4).