Solid state fermentation of maize (Zea mays) cob by Pleurotus ostreatus strain EM-1: Biopolymer profiles and cellulose degradability

The low digestibility and low protein content of maize cob are major limitations to its use as animal feed in Ghana. The possibility of enhancing the feed potential of maize cob through solid state fermentation byPleurotus ostreatus strain EM-1 was investigated. At the end of spawn run, lignin, cellulose and hemicellulose content had decreased by 42.3, 5.6% and 41.0% respectively. No further reduction in lignin content occurredthereafter. In contrast, after 28 days, cellulose and hemicellulose had been degraded by 36.0% and 58.5% respectively. A biphasic protein profile, characterized by a 6-fold increase by day 14, followed by a dramatic decline was observed. The rate of release of reducing sugars from spent maize cobs during incubation with exogenous cellulase was 400% greater than that of untreated maize cobs. The present findings indicate that the positive effects of P. ostreatus strain EM-1 on the nutritive value of maize cob appear to be optimal after complete colonization by mycelia. At this stage, maximum biodegradation of lignin had occurred, protein content was markedly elevated and the reduction in cellulose content was negligible. Thus, solid state fermentation by Pleurotus ostreatus strain EM-1 may be an efficient means of transforming maize cob into nutritive animal feed. Keywords: Oyster mushroom, delignification, animal feed, biodegradation, cellulose, hemicellulose

Differentiation of Two Pleurotus Species Based on the Restrictive Digestion Profile of the Internal Transcribed Spacer Region

Two oyster mushrooms (Pleurotus eous P-31 and P. ostreatus EM-1) are under either cottage industry or semi-commercial cultivation in Ghana. The latter (P. ostreatus) is already well known to the public and on the shelf of some leading supermarkets. There is morphological resemblance between the two species making it difficult for the untrained eye to distinguish between them except for the colour difference. In this study, molecular methods were em­ployed to differentiate among the two species. The Internal Transcribed Spacer ITS 1 and ITS 4 regions of the rDNA of the two oyster species were amplified by the conventional PCR using the universal primer pair, ITS 1 and ITS 4 followed by restrictive digestion with enzymes, (Hh I, Hinf I, Rsa I and Hae III). The two species could not be separated based on the ampli­fied bands only, as both produced a characteristic band size of 650 bp. Gel profiling showing restrictive patterns generated by the four enzymes indicated that only the Hae III restrictive enzyme was effective in separating P. eous P-31 and P. ostreatus EM-1. This is the first record of the separation of the Ghanaian Pleurotus species by molecular methods indicating their genetic differences

Human Enteroviruses isolated during acute flaccid paralysis surveillance in Ghana: implications for the post eradication era

Introduction: Surveillance of acute flaccid surveillance (AFP) has been used world-wide to monitor the control and eradication of circulating wildpolioviruses. The Polio Laboratory since its accreditation in 1996 has supported the Disease Surveillance Department for AFP surveillance. Thisstudy aims to isolate and characterize human enteroviruses from patients with AFP in Ghana. Method: Stool suspension was prepared from 308samples received in 2009 from the surveillance activities throughout the country and inoculated on both RD and L20B cell lines. Isolates thatshowed growth on L20B were selected for real-time RT-PCR using degenerate and non-degenerate primers and probes. RD isolates were however characterized by microneutralisation technique with antisera pools from RIVM, The Netherlands and viruses that were untypable subjected toneutralization assay using antibodies specific for E71. Results: Of the 308 samples processed, 17 (5.5%) grew on both L20B and RD cells while 32(10.4%) grew on RD only. All 28 isolates from L20B were characterized by rRT-PCR as Sabin-like polioviruses. No wild poliovirus or VDPV wasfound. However from the microneutralisation assay, six different enteroviruses were characterized. Among these, Coxsackie B viruses were most predominant followed by Echovirus. Three children from whom non-polio enteroviruses were isolated had residual paralysis while one child with VAPP found. The non-polio enteroviruses circulated throughout the country with the majority (20.7%) from Ashanti region. Conclusion: Thisstudy showed the absence of wild or vaccine-derived poliovirus circulation in the country. However, the detection of three non-polio enterovirusesand one Sabin-like poliovirus with residual paralysis call for continuous surveillance even in the post polio eradication era

Characterization of the dominant microorganisms responsible for the fermentation of dehulled maize grains into nsiho in Ghana

Nsiho (white kenkey) is a type of kenkey, a sour stiff dumpling, produced from fermented maize meal in Ghana. The dominant microorganisms responsible for the fermentation of nsiho were characterized by analysing samples from four traditional production sites at Anum in the Eastern Region of Ghana. During 48 h of steeping dehulled maize grains, the pH values decreased from 6.05 to 5.93 to 3.59 to 3.55, whilst titratable acidity increased from 0.02 to 0.03 to 0.27 to 0.32%. In the subsequent 12 h dough fermentation, the pH decreased from 6.02 to 5.80 to 3.52 to 3.46, whilst titratable acidity increased from 0.25 to 0.27 to 0.35 to 0.38%. The lactic acid bacteria population increased by 2 to 5 log units to concentrations of 107 to 108 CFU/ml during steeping and by 2 to 3 log units from 105 to 106 CFU/g to 108 to 109 CFU/g during dough fermentation. Yeasts counts increased by 3 to 4 log units during steepingand by 2 to 4 log units during dough fermentation. The most frequently isolated lactic acid bacteria responsible for nsiho fermentation were identified as Lactobacillus fermentum (47.1%), Lactobacillus brevis (25%), Lactobacillus plantarum (14.42%), Pediococcus pentosaceus (8.65%) and Pediococcus acidilactici, (4.8%). The dominant yeasts species were Saccharyomyces cerevisiae (47.6%), Candida krusei (29.1%),  Debaryomyces spp., (15%) and Trichosporon spp., (8.3%). This is the first  study to report on the micororganisms involved in nsiho fermentation.Key words: Nsiho, dehulled maize, kenkey, lactic acid bacteria, indigenous African fermented foods

Effectiveness of three different storage structures and curing process for the storage of sweet potato (Ipomoea batatas) in Ghana

Three different storage structures and two curing processes for the storage of sweet potato (Ipomoea batatas) were studied at the CSIR-Food Research Institute, Accra. Sweet potato roots initially cured under warm(30-35 °C) and very humid (90-95% relative humidity) conditions for 7 and 14 days were stored in local (traditional), pit, and clamp storage structures for 84 days. After 0-84 days of storage, the roots were sampled and physically assessed into wholesome, sprouted, fungalinfected, and insect and rodent-damaged. The decrease in percentage wholesome roots corresponded to an increase in percentage fungal-infected roots from 0 to 84 days of storage in all the three different storage structures. Clamp storage structure recorded the highest percentage wholesome roots (20.0%) compared to pit (16.3%) and local (0%) after 84 days of storage when roots were cured for 7 days. However, for 14 days cured roots stored for 84 days, local storage structure recorded the highest percentage wholesome roots (20%), pit (0%), and clamp (10%). Higher percentages of fungal-infected sweet potato roots were recorded from roots cured for14 days. Percentage sprouted roots was higher in clamp, followed by pit and local storage structures. Sprouting was delayed for sweet potato roots that were cured for 14 days in all the storage structures. Percentage damage of sweet potato roots by insect and rodent was lower inall the three storage structures compared to the fungalinfected sweet potato roots

D 5.3.2.1. Initial report on sensory and African consumer acceptance for Group 1. Project AFTER “African Food Tradition rEvisited by Research”

The sensory profiles and acceptability of Akpan, Gowe, Akpan and Kishk Sa'eedi were tested using a focus group discussion, a quantitative descriptive panel and consumer panels comprising African and/or European consumers as indicated in the table below. It should be noted that consumer testing of Kishk Sa'eedi was delayed because of the current social unrest in Egypt. The number of consumers interviewed by product and country is summarised in the table below. Consumer Class (and number): Country Benin Product Akpan African: 103Non-African74 Country Ghana Product Kenkey African: 110 Non-African90 Country Benin Product Gowe African: 141Non-African- Country Egypt Product Kishk Sa' eedi : African- Non-African- Sensory testing indicated that for each product, the sensory profiles widely differed. This was influenced by the raw material (Kenkey, Gowe, Akpan, KS), process (Kenkey, Akpan and KS) and addition of sugar/milk (Akpan and Gowe). The products also differed according to acceptance. Akpan - African and non-African consumers behaved differently with respect to acceptability. Europeans generally had a lower acceptability of Akpan products compared to Africans. This was probably due to the fact that most Europeans were not familiar with the product since when Europeans did report consuming Akpan, there were no differences in acceptability. Consumers' acceptance was significantly associated with fermented odour and milky taste. African consumers were more sensitive to the thick/concentrated texture and cereal taste whilst Europeans were more positively influenced by sweet taste but negatively by acidic taste. Kenkey – African and non-African consumers differed in acceptance of Kenkey. Non- African consumers mostly preferred the white kenkey and to a lesser extent banku. Ghanaian consumers generally liked all of the samples or preferred banku. Sensory attributes important for the white likers were whitish colour, fruity odour, smooth and non-sticky texture, a less sour product without a pronounced fermented odour, and a bland taste. Salty taste correlated significantly with acceptance for the banku likers, Gowe - The commonly consumed gowe were sensorially distinct products with differences between the sorghum and maize samples of gowe, but no significant difference was noted with sugar was added. Regarding consumer testing, three distinct patterns of consumer acceptability were observed, which were grouped as 'Sugary Gowe likers' or “Natural sorghum Gowe dislikers” (63.1%) followed by 'Sugary sorghum Gowe likers' (20.6%) and 'Indifferent Gowe likers' (16.3%). Saccharified malted and no-malted sorghum Gowe without sugar were the least preferred. Kishk Sa'eedi (KS) has distinct sensory attributes and variation. Consumer acceptance has still to be completed. The conclusions for reengineering are as follows: Akpan – there are two options being products suited to a) Akpan from Maize Ogi containing Sugar and Milk (OMsm) or b) Akpan from Ogi Sorghum containing Sugar and Milk (OSsm). However, since they are representative of classes of akpan type, any of these two classes could be suited for the reengineering. That is the case of OMs or OSs membership of OMsm and OSsm respectively. Kenkey - Two products should be considered, one adapted to both the European and the Ghanaian consumer 'white likers' and the second adapted to only the Ghanaian consumer 'all likers and 'banku likers'. Important sensory attributes which should guide re-engineering of the first product are whitish colour, fruity odour, smooth and nonsticky texture, a mildly sour product, and a bland taste. This may be achieved by a combination of processing factors including dehulling of maize kernels, use of mixed lactic acid bacteria/yeast starter culture containing high concentration of yeasts cells (for fruity odour), reduced fermentation period (to reduce sourness and fermented odour) and elimination of the aflata step (to reduce sticky texture). The second product should be a refinement of Ga/Fanti Kenkey and should also focus on improved packaging. Gowe - Gowe made from saccharified malted sorghum with sugar (SSaSFs) was the most accepted and appears to be the most promising for reengineering. KS – the consumer testing will take place later in 2012 These findings should be considered in combination with other AFTER deliverables relating to market and regulatory issues and technical feasibility. (Résumé d'auteur

Comparison of the microbial composition of African fermented foods using amplicon sequencing

Fermented foods play a major role in the diet of people in Africa, where a wide variety of raw materials are fermented. Understanding the microbial populations of these products would help in the design of specific starter cultures to produce standardized and safer foods. In this study, the bacterial diversity of African fermented foods produced from several raw materials (cereals, milk, cassava, honey, palm sap, and locust beans) under different conditions (household, small commercial producers or laboratory) in 8 African countries was analysed by 16S rRNA gene amplicon sequencing during the Workshop “Analysis of the Microbiomes of Naturally Fermented Foods Training Course”. Results show that lactobacilli were less abundant in fermentations performed under laboratory conditions compared to artisanal or commercial fermentations. Excluding the samples produced under laboratory conditions, lactobacilli is one of the dominant groups in all the remaining samples. Genera within the order Lactobacillales dominated dairy, cereal and cassava fermentations. Genera within the order Lactobacillales, and genera Zymomonas and Bacillus were predominant in alcoholic beverages, whereas Bacillus and Lactobacillus were the dominant genera in the locust bean sample. The genus Zymomonas was reported for the first time in dairy, cereal, cassava and locust bean fermentations

Proof-of-principle of a technology transfer of a dried blood virus neutralisation assay to a Gavi-eligible country

Background Global health clinical research is commonly led by high-income countries (HICs) as low- and middle-income countries (LMICs) face barriers to participate, including lack of financial and human capacity and lack of research environment. Respiratory syncytial virus (RSV) vaccine development is also led by HICs, while LMICs carry the burden of life-threatening disease. Representative trials and research capacity strengthening in LMICs are needed to ensure global vaccine access and equity. This study aims to transfer an RSV neutralisation assay, which uses live cells and virus with inherent high variation, to a country eligible to receive support from the Gavi, the Vaccine Alliance. Methods Using a train-the-trainer approach, a Ghanaian researcher was trained in the Netherlands on the dried blood-based RSV neutralisation assay. Subsequently, a Dutch researcher visited Ghana to support the process of adapting the technique to the Ghanaian setting. In a previously validated RSV neutralisation assay on dried blood, Hep-2 cells were infected with a serial dilution of sample-virus mixture to determine the half-maximal inhibitory concentration. Fifty-one dried blood and serum samples were tested in parallel in both countries to assess concordance. Results Training and technology transfer was deemed successful, which was defined as neutralisation measurements by the Ghana team and high concordance (Lin's concordance correlation coefficient (CCC)>0.8). Neutralising capacity measured in identical samples in Ghana and the Netherlands correlated highly (Lin's CCC=0.87; Spearman rho=0.89) but was systematically lower in Ghana than the Netherlands. Conclusion We show successful transfer of an RSV neutralisation assay, thereby strengthening the laboratory research capacity in a Gavi-eligible country. Reliable measurement of RSV neutralising antibodies in a Gavi-eligible country and the use of dried blood can contribute to inclusion of LMICs in RSV vaccine development and access