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Tadmor, Y., E. Jefthas, J. Goliath, M. Smith, P. Langenhoven, D. Acquaye, R. Juliani, W. Letchamo, E. Renaud, N. Zimba, I. Raskin, J. Brown, and J.E. Simon. 2002. Quality assurance and quality control for African natural plant products from the ground up. p. 93–97. In: J. Janick and A. Whipkey (eds.), Trends in new crops and new uses. ASHS Press, Alexandria, VA.

Quality Assurance and Quality Control for African Natural Plant Products from the Ground Up

Ya’akov Tadmor, Elton Jefthas, Jackie Goliath, Marianna Smith, Petrus Langenhoven, Dan Acquaye, Rodolfo Juliani, Wudeneh Letchamo, Erica Renaud, Noah Zimba, Ilya Raskin, Jerry Brown, and James E. Simon


Development of a quality assurance system for new botanicals, which are not internationally well-known for health and nutrition, is challenging. Consumer awareness and acceptance of new products must be developed before real markets can be successfully established. Producers must understand consumer demands and develop methods of production that meet those demands of product quality and efficacy, which exceeds or corresponds to international standards. Producers, marketers and scientists must work together to develop and introduce a product that will bring a reasonable return to the producer, while the consumer will receive a high quality, healthy, and safe product.

The USAID co-funded “Agribusiness in Sustainable Natural African Plant Products” (ASNAPP) project ( was initiated in 1999 to help develop the natural products sector in sub-Sahara Africa in a socially and environmentally sensitive manner. ASNAPP uses a market-driven, commodity-systems approach, which minimizes the risk to growers, and is focused on crop clusters such as teas, dyes, spices, and aromatic plants. A sub-focus of the project is the commercialization of traditional medicinal plants that can assist in primary health care. ASNAPP uses ongoing training programs to promote organic and sustainable production methods, business development skills and education. The main services that ASNAPP provides are: Local Capacity Building–Farmer and Producer Associations; New Crop Development and Technology Transfer; and Quality Control (QC) and Quality Assurance (QC) of Plant Sourcing through Processing and Market Development.

One of the major objectives of the quality control component of the ASNAPP program was to establish a product-tracking system for the cultivation, sustainable harvesting, shipping, quality control, and quality assurance of plant products, either nationally or internationally, such as was proposed in the WHO Guidelines for the Assessment of Herbal Medicine. The detailed objectives of the product tracking system are to: (1) provide farmers with avenues to develop sustainable collection and cultivation methods; (2) provide a system to track the flow of products through the ASNAPP organization; (3) provide an internal interactive feedback system; (4) ensure authenticity of African botanical products; and (5) ensure quality control for internal and external purposes.

ASNAPP had to establish standard procedures for the tracking system of African plant products produced and harvested from cultivated plots or collected from the wild by rural African farmers, while maintaining the genetic diversity of the wild species and utilizing sustainable agriculture and collecting methods. Once these procedures were developed, we needed to educate ourselves to utilize them routinely and properly. Together, these steps also provide the foundation for the monitoring and assurance that Good Sourcing Practices (GSP) and Good Agricultural Practices (GAP) were adhered to in the commercialization of the botanical products.

The current manuscript describes how we established and institutionalized procedures for natural African plant products for proper species (botanical) identification, methods of cultivation, and introduction or domestication. The paper also describes how we developed sustainable collection and processing methods, seeds and product sourcing, monitor and improved chemical and agronomic traits, harvesting and drying methods, packaging and sample forwarding methods, and quality control and assurance for African natural plant products developed through ASNAPP, bound to local, regional, and international markets.


The demand for high quality, safe, effective, and clean natural plant products and their formulations with various substances have been growing significantly in the industrialized world. In the past, herbs and essential oil bearing plants were largely harvested from the wild and brought to the market without many questions asked about their origin, methods of cultivation, botanical identity, purity, safety, and efficacy. However, with further improvements in communication and education, there has been a growing consciousness in industrialized countries about personal health, environmental safety, sustainable harvesting, and loss of genetic diversity resulting from extensive wild harvesting of the medicinal species. This increased awareness has lead in the US, Canada, and Europe, to a wider use of alternative medicine practices, which include the use of botanicals as medicinals though purchased as dietary supplements, by the consuming public. This phenomenon has been largely media and market driven rather than a scientific/medically driven movement. Yet, with increased consumer usage, and increased advertisement, the expectations by the public have also increased leading to a more stringent demand for quality and traceability. Among all botanical producing continents, Africa has been the smallest contributor to the international botanical marketplace. In addition to the lack of strong marketing tools and material basis for African natural products, botanical misidentification, inappropriate methods of collection and processing with undesirable foreign matters, and microbial contaminants in the products, have all contributed to the negative impact against healthy competitiveness of the African natural plant products in the international markets.


Results of preliminary organoleptic tests of initial bush teas coming from Africa are presented in Table 1. These samples suffered from high microbial counts, and large variation in the color, aroma, flavor, and taste of the teas. In fact, this indicated that the teas are not yet acceptable for consumers and suggested that QC procedures could bring substantial improvement to such African products. Moreover, all the samples we had received for testing had very high microbial counts, unacceptable by modern food and food supplements markets. Various factors might have contributed to the variations or inconsistencies in all the parameters indicated above; plant stage at harvesting time, method of processing, storage, packaging, and shipment are the major environmental ones. The samples we did receive did not reflect actual commercial African tea products as those would have been pasteurized, processed, and tested but rural communities producing and/or collecting for the first time these African bush teas.

Table 1. Organoleptic analyses, total microbial counts, phenolic compounds content, and antioxidant activity of different Rooibos and Honeybush teas sent from Africa to the US.

Sample identity Color Aroma Taste pH Total
(mg/g SE)
(mg/g SE)
001 Rooibos tea 4 3-4 5 6.67 >106 55.40.6 94.62.4
002 Rooibos tea 4 2-3 5 6.65 >106 28.00.6 65.37.9
003 Honeybush tea 3 2-3 5 6.66 >106 23.30.6 42.78.6
004a Honeybush tea 4-5 1-3 5 6.67 >106 42.30.6 84.92.4
004b Honeybush tea 3-4 1-2 3 6.66 >106 33.70.3 76.39.1
004c Honeybush tea 3-4 3-4 1 6.68 >106 47.71.2 92.24.8
005 Rooibos tea 3 1-2 1 6.67 >106 69.21.2 125.82.2
006 Rooibos tea 3 2-3 2 6.66 >106    
006a Rooibos tea           35.20.6 81.25.0
006b Rooibos Tea           127.62.4 311.436.9
007 Rooibos tea 3 1-2 3 6.66 >106    
008 Rooibos tea 4 2-3 2 6.66 >106    

zTotal phenolic compounds, results are expressed as gallic acid equivalents, mg gallic acid/g tea.
yTrolox equivalent antioxidant capacity, mg Trolox/g tea (Trolox is a water soluble analogue of vitamin E).

Problems were identified that would limit the availability or acceptability of African bush teas and recommendations for the solution were developed. Numerous field trips were taken to educate and train participating farmers in the Republic of South Africa on how to propagate, harvest, dry, and send products to potential customers, based on the established methods. Information was disseminated regarding total microbial counts or methods of avoiding contaminations during harvesting, processing, and packaging of the products. Lack of well-trained African partners who understand the issues of quality and standards for the preparation of the raw material from the ground up was another problem that was identified during this work. In addition, the participants in the program were able to learn by participation in the construction of the basic standard operation procedures (SOPs) for tracking plant materials from cultivation or wild harvesting, processing to packing and shipping the products to their final destinations. Lower numbers of microbes per gram of tea has been achieved through the ASNAPP program’s expert training activities and close monitoring of the complete developmental system.

Procedures were designed and set up for the production and supply of the raw materials to the international, local, and regional natural products markets. We developed paper based and electronic tracking systems for agronomic practices, plant introduction, cultivation, wild collection, drying, and in-house quality control procedures, that could be well understood and handled by participating farmers, middlemen and processors, trading and promotional companies, including packing and forwarding companies. Fact sheets on each African botanical were developed and when needed translated into local languages for greater effectiveness. All such fact sheets and QC procedures are on-line at

Our procedure starts with the growers or wild collectors. An ASNAPP member accompanies the production procedure and completes the Feedback Report for the Cooperating Farmer. At this stage, a code number is assigned to the plants. This code number will remain with the sample until it is sent to interested private companies. The feedback form is completed during the growth of the plants, ensuring standardized methods for monitoring plant growth conditions. This form provides estimations of realistic yields and enables us to associate growing conditions with problems arising later in the process. When a sample of the plant product is ready to be shipped to the US, for further analyses and for attempts to promote the product in commercial markets, a second form, SOP-I, is completed. This form, completed by the sender, is sent with the plant product sample. It gives the receiver necessary data about the identity of the product and the processes it has gone through. Most importantly, it gives the product an ASNAPP identification number that will escort it through the QA/QC procedures. Upon receiving the plant product with the SOP-I form, we next complete the SOP-II form and send a copy to the sample’s sender. This form confirms the sender that his/her sample was received, its condition as received, and the analyses that we plan to conduct. Sub-samples are now analyzed. The initial analysis assesses possible microbial contaminations. When we determine that the sample is safe for human consumption, from a microbial aspect, we can conduct organoleptic, physical, and chemical analyses. Once the analyses are completed, in collaboration with ASNAPP Africa, we complete the SOP-III form. This form contains general data about the product and a summary of the conducted analyses and evaluations. Detailed data is attached to this form as numbered attachments. The SOP-III form, and its attachments, includes the science-based information used to write the product’s specifications sheet necessary to promote the commercialization of our plant products. The route by which a plant sample is going, from growers and collectors to private companies in the US, and the route of the described forms, is summarized as a flow chart in Fig. 1. In order for the Product Tracking System to be effective, it must be used by all members, who must be aware of their expectations and responsibilities within the Product Tracking System. For that purpose, we also developed an easy to use interactive on-line tracking system that is available in the members section of the ASNAPP website (

Fig. 1. A flow chart describing the ASNAPP operation procedure by which a botanical sample and the standard operating protocols (SOPs) move through the QC system from the collection to the marketplace. ASNAPP Africa is responsible for the assignment of a code number, completing FAS-1 (QC/QA of production and processing), shipping of plant product accompanied by SOP-I and collaborating in the completion of SOP-III. ASNAPP USA is responsible for receiving, analyzing and distribution of the plant sample, completing SOP-II, SOP-III (QC/QA of product) and the product’s specifications sheet.


It is of a paramount importance to confidently determine the botanical identity of the plant material that ASNAPP collaborators are cultivating, harvesting, or introducing into cultivation for further marketing. The safety of botanicals may derive from a variety of sources in many guises, and involve the practice of a range of scientific disciplines in addition to traditional reputation and anecdotal testimony. However, it must be clearly understood that strong emphasis must be given not only to precise botanical identity, but also to the identification of the differences in selected species based on their chemical profiles, giving the opportunity for variations in efficacy and areas of applications. Authoritative authentication of the plant identity at the grower/supplier end is unquestionably the most effective means of promoting quality, accuracy, and consistency of the botanical products. At this stage we are in the process of training ourselves to conduct confirmed identification of botanicals. In SOP-III, we need to ascertain whether botanical authentication was confirmed. At Rutgers we developed the necessary infrastructure to develop DNA fingerprints for all African plants products in order to ensure that botanical identity authentication is based on objective scientific tools.


In view of lack of appropriate training on botanicals, there appears to be a pervasive tendency on the part of consumers and medical practitioners to accept as gospel what the manufacturer declares to be the contents on the label of herbal preparations. This could damage the natural products industry and may erode the confidence of the consumers. ASNAPP has a program to train its stakeholders to have a scientific understanding of the new African natural products in a neutral manner.

So far, there has not been any centralized analytical lab for the testing of African botanicals. However, there are several internationally renown labs at universities and research institutes in sub-Saharan Africa with excellent facilities and scientists working on the chemical characterization, food, and biological applications of medicinal plants and botanicals. In addition, at Rutgers University a program has been initiated to establish a research program with appropriate partners who are well versed in African flora and culture. This ASNAPP program will also assist African producers, suppliers, processors, researchers, regulatory agencies, and marketers, and enable them to get into a healthy market competition bringing their own products to local, regional, and international markets. For example, some of our major products are teas. One of the attributes of the African herbal teas is their antioxidant capacity/activity. When we analyzed several samples of honeybush and rooibos teas for antioxidant capacity, we noticed large variation among samples (Table 1). This variation resulted from genetic variation or from environmental conditions including processing and handling practices. In order to provide a high quality, uniform, product, such variation needs to be decreased, and reach a minimum standard of acceptability for use in marketing claims. Our tracking methods are able to identify these sources of variation, characterize whether they are genetic or environmental, and give recommendations to decrease this variation and to ensure a uniform healthy product for the customer. Another example is finding new uses for traditional products. Essential oils are traditionally used in the cosmetic and food industry for improving aromas. We screened African essential oils for their antimicrobial activity to promote them as natural food preserving compounds. The effect of essential oils on Aspergillus niger, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Saccharomyces cerevisiae growth were measured on logarithmic phase culture in liquid media (Table 2). Our results indicate that some of the African essential oils have the potential to be used as food preservatives and we will continue to promote this possibility.

Table 2. Antimicrobial activities of selected African essential oils.

Plant names Aspergillus
Aframomum melegueta (Paradise grain) 5 2 0 5 3
Barosma betulina (Buchu) 5 0 0 5 5
Barosma crenulata (Buchu) 5 5 5 5 5
Ocimum canum (African beauty basil) 5 4 0 5 5
Pellargonium graveolense (Geranium) 5 3 0 5 5
Piper nigrum (Black pepper) 5 5 3 5 5
Ravensara aromatica (Ravensara) 5 5 0 5 5
Tagetes minuta (Tagetes) 5 5 4 5 5
Zingiber officinale (Ginger) 5 0 0 2 5

z0 = no activity; 1 = very low activity; 5 = complete kill or inhibition of growth.

Based on the internationally harmonized standard operation procedures, from the bottom up, enforcement of the regulations that apply for commercial medicinal plant products will have a meaning, while ensuring their identity, safety, quality, purity and strength. Certificates can be issued by recognized scientists or institutions that identify products based on currently accepted Latin binomials and synonyms, with associated authority, and usual common names, as well as the origin, site, and date of harvest of the crop. Only then will consumer confidence and the promising potential of phytomedicines be firmly advanced.


To this end, it is envisioned that many African plants will be screened for special qualities and applications, and improvement programs will be implemented through genetic selection, chemotype differentiation, and agronomic studies that will enable confident distinction and certification. We consider our new program of ASNAPP as suitable for both screening and commercialization. Our program offers a good model for the natural products industry all over the world. Moreover, ASNAPP is a good model system for a scientific and economical collaboration between African and American peoples.