Academic Journal of Science, CD-ROM. ISSN: 2165-6282 :: 07(02):253–268 (2017)

MICROBIOLOGICAL AND SENSORY EVALUATIONS OF SELECTED PRODUCTS (GARRI, , FLOUR AND ) FROM WHITE AND YELLOW VARIETIES

E.N. Onyeneke and N.C. Ohazurike

Imo State University

C.N. Ubbaonu

Federal University of Technology

Cassava also called yuca, Mogo, Manihot, mandiola and Kamoteng kotiox, a woody shrub of the euporbiaceae (spurge family), ( Manihot esculenta crantz ) is a tropical staple crop grown for its tuberous starch roots (Westby, 2002). Cassava ( Manihot escutenta) root is the most perishable of all the root and tuber crops and should never be eaten raw as the root composes of small quantities of cyanogenic glycosides (Okaka, 2004).Cassava roots generally deteriorate very quickly soon after harvest (Onwueme, 2008).Most spoilage organisms are soil or air born spores from field, harvesting and packing machinery (Frazier and West Hoff, 1991).Two cassava varieties TMS98/0505(white) and TMS05/0473 (yellow) were processed into four different products (garri, fufu, flour and tapioca) each and the microbiological and sensory evaluations of these products were evaluated. Study aimed at efficient and appropriate handling of products to promote the totality of the period within which the product is expected to retain its acceptable characteristic quality under normal condition before consumption. Methodolody : Products were analysed for organoleptic properties in wet/fresh conditions using 5point hedonic scale and randomly selected panelists to ascertain the sensory qualities, also samples were cultured for 48hr microbiological examination. Results- showed that microorganisms identified and isolated from samples include; Enterobacterspp, Staphylococcus spp, Klebsiells spp, bacillus, Lactobacillus, protuse vulgaris, Micrococcus spp for bacteria Identification while the fungi identified includes penicillum spp, Aspergillus spp, Rhizopus spp , Mucor spp . The total microbial count ranged from 9.0x10 2 cfug- 1 for white cassava Fufu mash (sample 1) to 4.8x102 cfug- 1 in white cassava Flour (sample 5).The samples showed combined positivity and negativity to the morphological, microscopic and biochemical test processes for bacteria and fungi. The sensory properties evaluation had values of result ranging from 6.3± 1.2 to 2.61±1.2 with yellow cassava garri (sample 4) having the highest value while yellow cassava fufu mash (sample 2) had the lowest value and differing significantly (p>0.05) texture ranged from 6.1 ± 1.7 to 4.07 ± 1.8 .However, overall acceptability ranged from 6.31 ± 1.8 to 4.10 ± 1.2 for tapioca (sample 8) and yellow cassava flour (sample 6) respectively. The overall acceptability showed significant difference at (p>0.05) among all other samples. Cassava products have appreciable level of microbial load. And both the white and yellow varieties are similar as they showed no much difference in their microbial content. Cassava products has significant level of microbial load hence there is need for proper sanitary condition during

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processing to avoid health risk among its consumers, especially garri forms the basic staple food in and some African countries

Keywords: Yellow and White cassava products, Microbiological assay, Sensory properties.

Introduction

Cassava also called yuca, Mogo, Manihot, mandiola and Kamoteng kotiox, a woody shrub of the euporbiaceae (spurge family), native of South America, Cassava ( Manihot esculenta crantz ) is a tropical crop grown for its tuberous starch roots (Westby, 2002). Every part of the plant can be utilized, but the starch roots are by far the most commonly used (Westby, 2002). Cassava (Manihot esculenta crantz) roots is the most perishable of all the root and tuber crops (Okaka, 2004). One of the advantages cassava has over other starch crops is the variety of uses to which the roots can be put (Nweke et al ., 2002).Apart from being a staple food for humans especially in , it also has an excellent potential use as livestock feed, and in textile; plywood, proper, brewing, chemical and pharmaceutical industries (Nweke et al., 2002). The white cassava (Manihot dulcis) (Nwocha) specie and yellow ( Manihot escunlenta , (TMS 01/1368/ or UMUCASS 36), are two distinct cassava types. The yellow cassava is a similar to the white cassava, but it has a yellow flesh inside the root, which is generally white in ordinary varieties (Egesi, 2011). Traditionally, cassava processing methods in use in Africa probably originated from tropical America, particularly northeastern Brazil and may have been adapted from indigenous processing method (Kormawa and Akinde,2003).The processing methods includes peeling, steaming, slicing, soaking or steeping, fermentation, pounding, toasting, pressing, drying and milling. These traditional methods give low product yield which are also of low quality. Rapid urbanization in tropical Africa increase mobility in both rural and urban areas and the changing roles and states of woman have resulted in an unprecedented demand for convenient food.Added to these factors is the high cost of fuel for cooking in urban areas. Therefore, cassava processing and utilization technologies for the future should be able to improve traditional methods and develop low cost equipment with energy consumptions. Improved processing and utilization technologies should address issues related to farmers (producers) and consumers demands (particularly urban needs in future) and also economic factors and nutritional values knowledge of current traditional processing and utilization methods id its present urban patterns of consumption and changing urban needs will guide future strategies for cassava processing and utilization. According to food cultures, environmental factors such as availability of water and fuel, the cassava varieties used and the type of processing equipment and technology available (Olapade, et al. 2014) Fermentation of cassava consists of two distinct methods aerobic and anaerobic (Uzuegbu and Eke, 2001). Aerobic fermentation involves the peeling and slicing of cassava roots and surface drying for 1-2 hours and then heaped together, covered with straw or leaves and left to ferment for 3-4 days. The fermented moldy pieces are sun-dried after the mold has been scraped out. The processed and dried pieces (called “Mokopa” in Uganda) are then milled into flour which is prepared into a “fufu” called “kowan” in Uganda.The growth of mold on the root pieces increases the protein content of the final product three to eight folds (Sanni et al., 2010). This fermentation methods is also very popular in other parts of East Africa such as Tanzania, Rwanda and Zaire.For “Lafun” production in Nigeria. Peeled or unpeeled cassava tubers are immersed in a stream or stationary water (near a stream) or in an earthenware and fermented untilthe roots becomes soft. The peels are manually removed and the white tubers recovered pure, then washed sieved and pounded. The micro- organisms involved in “lafun” production includes; pichia enyehis, Candida tropicalis, geotricum Candida and Rhoditorula spp, Aspergiccus niger and penicilliun spp, lenconostoc spp and corynum bacterium spp (Oyewole et al .,1996). Microbial contamination of food and food products has been a serious threat to human health. Since micro- organisms differ widely in their optimal temperature for growth there are induced changes in nutritional E.N. Onyeneke et al. 255 quality and acceptable of the food product, (Schewan, 1997)has been reported that moisture content in food products supports the growth of microbes and generally, bacteria require more moisture than yeast and yeast more yeast than mould (Uzuegbu and Eke, 2001). The microbial spoilage of the food material should not be viewed as sinister plot on the part of micro-organism to deliberately deny us our food but instead as the normal function of these micro-organisms in the total ecology of all live organisms’ determination. A number of investigations have reported instances in which bacteria were found in various part of health plants (roots) particularly the storage organs (Frazier and West Hoff, 1991).Most spoilage organisms are soil or air born spores from field, harvesting and packing machinery. According to source findings, It has been shown that yellow cassava tuber contains more nutrients, Beta-carotene, Vit .C than other varieties of cassava. There is also need to investigate handling methods of cassava products and its-consumption as it is a health risk due to microbial load so as not to undermine its consumable qualities. The sensory perception is largely affected by personal preferences which in turn are a result of many factors from the sociological to the unique individual. For example, genetics, age, party experiences with food, culture, tradition and customs, the environment in which the food is consumed, and physiological reaction will all affect a consumer’s sensory experience (Iwe, 2002). However, Onwueme (2008) confirmed that manufacturers have to provide consumers with innovative options and new twists on favourite brands in order to succeed in this sensory-driven culture. Study therefore aimed at efficient and appropriate handling of products to promote the totality of the period within which the product is expected to retain its acceptable characteristics quality under normal condition before consumption.

Literature Review

Cassava ( manihot esculenta crantz) is a tropical crop grown for its tuberous starch roots (Westby, 2002), it was introduced in by the Portuguese (Considine, 1999). Cassava ( Manihot escutenta) root is the most perishable of all the root and tuber crops (Okaka, 2004).

- Nutritional Profile of Cassava

Cassava root is essentially a carbohydrate source, its composition shows 60-65% moisture, 20-31% carbohydrate, 1-2% protein and a comparative low content of vitamins and minerals. However, the root is rich in calcium and vitamin C and contains a nutritionally significant quality of thiamine, riboflavin and nicotinic acid (Chioma, 2012). Cassava starch contains 70% amytopectin and 20% amylase. Cooked cassava starch has a digestibility of over 75% (Chioma, 2012).

- Cassava Products and Utilitization

Cassava is the basic of a multitude of products, including food, (fufu, garri, tapioca) flour, animal feed alcohol, sweetened prepared food and biodegradable products(Eleazu and Eleaza’ 2012). Cassava tuber is processed into flour for several reasons including the prolongation of shelf life, detoxification via removal of cyanogenic glycoside(Crushing, heating) improving palatability and possible improvement in nutritional quality .cassava flour is available in several forms including granules, flakes, pellets ,and plain flour. it is used as a thickener in among other uses(FAO,2003). However, the traditional methods of processing cassava into garri have been found to be deficient in reducing the amount of cyanide in the product (Achinewu et al .,1998).

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According to Asegbeloyin and Onyimonyi (2007) during the first stage of garri production, the bacterium corynebacteria manihot attack the starch of the roots, leading to the production of various organic acids (lactic and formic acid) and the lowering of substrate pH in the second stage, the acid condition stimulates the growth of the mould, geotricum candida , which proliferates rapidly ,causing further acidification and production of a series of aldehydes and esters that are responsible for the taste and aroma of garri. The optimum temperature for the fermentation of garri processing is 35% increasing up to 45 0C (Kolawole et al .,2009).

- Sensory Properties and Evaluation of Products.

The sensory properties of an edible products according to Adeyemi et al .,(1992) under pins today’s consumers desire for experimental pleasure and sensation from products. Consumers place significant value on the hedonistic benefits of foods and products and are looking for particular attributes that engage all their senses and inspire a deeper relationship with the product.

Methodology

The cassava varieties TMS98/0505(White) and TMS05/0473(Yellow) were obtained from Imo State Agricultural Development Project (ADP), Owerri. The tubers were healthy and free from all forms of mechanical injury, which might be a possible source of contamination.

-Preparation of Samples

Each of the cassava varieties were processed into four samples (Fufu mash, garri, flour and tapioca). The soaking and fermentation aspects of the processing was done in the women in Agriculture (W.I.A) house in Imo-ADP while the further and other processing activities were carried out in food science technology laboratory, Imo-State University, Owerri .

-The Samples

There were a total of eight (8) samples:S1- Fufu mash made from white cassava, S2-Fufu mash made from Yellow cassava ,S3-garri made form white cassasva,S4-garri made from yellow cassava , S5-Flour made from white cassava , S6-Flour made from yellow cassava , S7-Tapioca made from white cassava , S8- Tapioca made from yellow cassava .

- Sample Processing

Fufu Mash

The method described by Oyewole and Odunfa (1989) were followed.10kg of each species were cleaned; hand- peeled tuber were soaked in water in a plastic container for the fermentation process under ambient condition (30 0c+ 2 0c). The duration of fermentation was to last for 3 days for different species of cassava in different fermentation tanks. The resulting retted roots were hand- pulverized and wet- sieved to obtain the sedimented wet fufu mash.

E.N. Onyeneke et al. 257

Garri

Garri were produced by process described by IITA 1990). The cassava tuber (10kg) of each species were peeled manually using a stainless steel kitchen knife. The peeled tubers were washed and grated. The grated meal were then packed into Hessian bag and allowed to ferment for 2 days. The fermented pupl was dewatered using the hydraulic press. The pressed cake was broken into pieces with hand and sieved with a wire mesh screen. The sieved pulp was garified inside a wide shallow cast iron pot and stirred constantly over fire until well dried .it was cooled and packaged.

Flour

Cassava flour is the product obtained from freshly matured cassava roots by hand- peeling 10kg of each species and washing followed by grating with mechanical grater and dewatered and then sun dried in a thin layers before milled finely to obtain cassava flour.

Tapioca

10kg of each cassava varieties were used for preparing tapioca by cutting the cassava into small pieces to 10cm length, followed by washing in clean water and then boiling for ten (10) minutes at 100% and allowed to cool. The cooled cassava were peeled before cutting using a sharp kitchen knife. The chopped cassava were then soaked in water for a day so that the cyanide will leach into the water.

-Preparation of Media

The materials used such as glass wares, micro-pipette etc were properly sterilized in the oven. All the media used were prepared according to the manufacturers instructions and autoclaved at 12 0C for 15 minutes (Streaking technique)

-Identification of Microbes

The bacteria isolates were identified by carrying out some test such as coagulase, catalase, colour utilization, indole test, gram staining, methyl red test, motility test.

Gram Staining

The principle of staining focuses on the ability of the bacterial cell wall to retain the primary dye (methyl violet or crystal violet) after decolourization with 75% alcohol and its ability to resist secondary dye Steps;- * A smear of the bacterial (Test organism) was prepared on separate slides (grease free slides) * Each smear was air dried heat fixed by passing the slides over a flame for three (3) minutes with crystal violet for about 30-60 seconds. * The dye was quickly strained and washed with Lugios iodine which was left for 80 seconds. * The iodine was drained off and slides were gently washed under tap. * The slides were flooded with dilute carbol fushin for 30 seconds after which they were drained, washed, bottled dry and viewed under oil immersion. 258 Microbiological and Sensory Evaluations of Selected Products ...

Motility Test

This test was performed to identify the test organism with the presence of locomotory organ for movement. The test was carried out according to Monica Cheesebrough (2000).

Principle

When suspended in appropriate fluid (peptone water) and expired microscopically, many bacteria are seen to be motile (Moving from one position to another). Steps * A small drop of bacteria suspension was placed on a slide and cover glass. * This was examined for motile organism using 10L and 40X.

Objectives

Positive (true) motility was distinguished from the spot vibrating movement (Brownian movement) which is seen by all micro-organisms and particles when suspended in fluid.

Catalase Test

This test was used to different those bacterial that produce the enzyme catalase eg; staphylococcus aureus and non- catalase producing streptococcus . The test was carried out as described by CheeseBrough (2000)

Principle

Catalase acts as a catalyst in the breakdown of hydrogen peroxide to oxygen and water. An organism is tested for catalase production by bringing it into contact with hydrogen peroxide bubbles of oxygen are given off if the organism is a catalase producer. The culture should not be more than 24hrs old. STEPS * 2-3mls of hydrogen peroxide solution were poured into a test tube. * several colonies of the test tube organism were inoculated using a sterile wooden stick. * Bubbling was observed.

Coagulase Test

This test was performed to identify staphylococcus aureus which produces enzyme coagulase.

Principle

Bound coagulase (Caumping factor) which converts fibrinogen directly to fibrin .It can be detected by the chumping of bacterial cells in the rapid slide test.

E.N. Onyeneke et al. 259

Steps

* 2 drops of distilled water water were placed on each slide. * The test organism was emulsified in each of the drops to make two thick suspension. * A loop full of plasma was added to one of the suspensions and mixed gently chumping was observed within 10minutes.

Result

An agglutination within 10 seconds indicate position test while no agglutination indicate a negative test.

Indole Test

This is carried out in order to identify enterobacter, most strains of Escherichia coli, etc and other organisms that breakdown aminoacid tryptophan with the released indole.

Principle

The test organism was cultured in a medium which contains tryptophan. Indole production was detected by kovac’s reagent which contains 4(p) dimethyl amino benzaldehyde. This reacted with the produced a red coloured compound.

Methyl Red Test

This was recommended for the differentiation of coli aerogene group. Coliform organisms produce high acidity which was constant while the aerogenes produce less acidity which becomes alkaline on continued incubation.

Steps

* About 5mls of Mr Bralt was dispensed into tubes and sterilized at 121 0C for 15minutes * Each tube was inoculated with a pure culture of isolates. * After 5 days incubation at 35 0C, 5 drops of methyl red reagent was added to the culture.

Result

A positive reaction was indicated by a discreet red colour while a yellow colour indicated a negative reaction.

Urease Test

Testing for urease enzyme activity is important in differentiating Enterobacteria protein strains which are strong urease producer while enterocolitica also show urease activity (weakly at 32 0C-37 0C). Salmonellae and shigellae do not produce urease.

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Principle

The test organism is cultured in a medium which contains urea and the indicator is phenyl red when the strain is urease producing. The enzyme will breakdown the urea(hydrolysis) to give ammonia and carbondioxide. With the release of ammonia, the medium becomes alkaline as shown by a change in colour of the indicator to pink red.

Oxidase Test

This test is carried out to determine the organism that produce enzyme oxidase Cheese Brough (2000) Steps * A grease free fiter paper was placed on a clean petri dish. * 2 drops of freshly prepared oxidase reagent of methyl-p-phenylene –diamine was added on the fiter paper. * A sterile long wire was used to collect a colony of test organism and smeared on the filter paper.

Result

A blue purple colouration within two seconds indicated a positive oxidase test.

Enumeration, Isolation and Characterization

The total microbial count was done with digital colony counter. The total microbial population was expressed as colony forming units per gram(cfug-1) of sample. Characteristic bacteria isolates were identoified based on colonial morphology ,microscopy and biochemical tests (Holt et al .,1994).And characteristic microscopy with reference to standard atlas and keys(Samson and Reneen Hocksha, 1988; Tsuneo, 2010).

Sensory Evaluation

Sensory evaluation was carried out in accordance with hedonic sensory test by (Iwe, 2002).Ten Man panelist tested the products on the scale of 1-7 based on taste, texture appearance and overall acceptability.

Statistical Analysis Of Sensory Results (Anova)

All the sensory results will be analysed using randomized block design (ANOVA) and the significant difference tested using Least significant difference test.

E.N. Onyeneke et al. 261

Cassava tubers

Peeling

Washing

Immersion in water (72hrs)

Fermentation (3 days )

Mashing

Sieving

Baging

Dewatering

Fufu mash

Figure 1. Flow process for the production of cassava -fufu mash from cassava tubers (for both varieties)

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Cassava tubers

Washing

Peeling

Washing

Grating

Baging & fermentation (48hours) 

Pressing /dewatering

pulverizing

Frying/toasting (90 0c)

Cooling

Garri

Figure 2. Flow process for the production of cassava garri from cassava tubers (for both varieties)

E.N. Onyeneke et al. 263

Cassava roots tubers

Harvest/sorting of cassava (Select fresh, mature cassava roots without rot)

Peeling

Washing

Wet-grating (Mechanical grater)

De-watery (screw or hydraulic press)

Pulverize

Sundry in a thin layer (polythene bag)

Dry-milling

Sieving

Cassava flour

Package

Figure 3. Flow Process for the production of cassava flour from cassava tubers (for both varieties) Source: Onabolu, Abass and Bokanga (1998)

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Cassava tubers

Cutting (10cm length)

Washing

Boiling (100 oc)

Peeling

Cutting

Soaking in water (24hrs)

Washing & rinsing

Tapioca (Abacha Mmir)

Figure 4. Flow process for the production of cassava tapioca from cassava tubers (for both varieties)

Results

Table 1. Results of Micro Organisms Identified and Isolated In the Eight (8) Samples Type Micro Organisms Identified Bacteria Enterobacteria, Spp, Staphylococcus Spp, Klebsiella Spp, Bacillus, Lactobacillus, proteus Vulgaris Mucrococcus Spp Fungi Penicillrum Spp, Aspergillus Spp, Rhizopus Spp, Mucor Spp.

E.N. Onyeneke et al. 265

Table 2. Microbial count of the different samples of the cassava products.

SAMPLES TOTAL MICROBIAL COUNT 1 9.0 x 10 2cfug -1 2 8.7 x 10 2cfug -1 3 6.0 x 10 2cfug -1 4 5.4 x 10 2cfug -1 5 4.8 x 10 2cfug -1 6 4.9 x 10 2cfug -1 7 6.8 x 10 2cfug -1 8 6.5 x 10 2cfug -1

Table 3. Shows the Characterization and Isolates Bacteria In the Samples Based On Morphology, Microscopy And Biochemical Test

Sample Gram Motility Catalase Coagulase Indole Metitylred Urease Oxidase Isolate Organisms Test Test Test Test Test Test Test Test

S1 + + + + - - - + Staphylococcus ssp

S2 + + - + + + + + Entrobacteria ssp

S3 + ------+ Klebscella spp

S4 + + + - + - - - Bacillus

S5 + - + + - - + + Lactobacillus lactic

S6 + ------Micrococcus spp

S7 + + - - - - - + Proteous vulgsris

S8 - + + - - + + Lactobacillus brevis

Table 4. Shows the Characterization and Isolates Fungi In the samples based on Morphology, Microscopy and Biochemical test

Sample Gram Motility Catalase Coagulase Indole Metitylred Urease Oxidase Isolate organisms test Test Test Test Test Test Test Test

S1 + - + + - + - - Pennicelium spp

S2 + + - + - - + + Aspergillus niger

S3 + - + + - + - - Mucro spp

S4 + - + + - + - - Rhizopus

S5 - - + - + + - - oxysporium

S6 + - + + - + - - Penntcellum spp

S7 + - - + - - + + Aspergillus flavus

S8 + - + + - + - - Micror racemoscus

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Table 5. Mean Results of Sensory Properties Of the Eight (8) Samples of Cassava Products

Samples Taste Texture Appearance Overall acceptability 1 2.86±1.6 ab 5.2±2.0 a 5.3±1.9 a 5.86±1.8 a 2 2.61±1.2 a 5.3±1.36 a 5.42±1.3 a 5.71± ab 1.2 3 6.10±1.8 a 5.9±1.8 a 5.89±1.7 a 6.28±1.8 a 4 6.3±1.2 a 6.1±1.1 a 5.98±1.8 a 6.01±1.8 a 5 4.01±1.2 ab 4.30±1.6 a 4.56±1.7 a 4.20±1.6 b 6 4.03±1.2 b 4.10±1.3 a 4.07±1.8 a 4.10±1.2 a 7 5.80±1.8 a 5.67±1.8 a 5.18±1.1 a 5.26±1.8 a 8 5.96±1.6 a 5.90±1.2 a 6.01±1.7 a 6.31±1.8 a

Discussion

Table 1 - The result in table 1 showed the microorganisms identified in the samples to include; Bacteria Entrobacteria SPP, Lactobacillus, Proteus Vulgoris, and micrococcus SPP. Aspergillus SPP, Rhizopus Sspp and Mukcor SPP. This result is in line with the work OLopade et al . (2014) and Kolowale et al ,. (2009) which identified some microorganisms associated with fermented cassava products .However they identified Leuconostoc SPP which was not isolated in this work. Table 2 – Showed the total microbial count in the samples. The microbial count ranged from9.0 x 10 2cfug- 1 to 4.8 x 10 2Cfug-1, sample1(fufu mash produced with white cassava variety) had the highest count and sample 5(cassava flour produced with cassava) showed the lowest count. This is similar to the results obtained by Olopade et al (2014) which examined the microbiological content of garri sold inota Ogun State Nigeria. Table 3- This result showed the microbiological, microscopic and biochemical characterization and isolation of bacteria. It showed gram staining appearing positive in all the samples and for the micro organisms isolated and other varying positive and negative results in motility, catalase, coagulase, indole- methylred, urease, oxidase tests. These are similar to Kolawale et a l (2009). Result on the effects of colour light frequencies on the nutrient and microbial composition of cassava product in which gram staining showed positive to all bacteria isolated. Table 4 –Shows the result of fungi characterization of the isolates in the samples, the fungi pennicelium SPP A. Niger, Mucor SPP, Rhizopus, Oxysporium, A. Flavis, M. racemoscus showed varying positive and negativity to the biochemical tests carried out. This is in line with the result of (Kolawale et al ,. 2009). Table 5- shows the result of the evaluation of sensory properties, the taste value ranged from 6.3±1.2 to 2.86±1.6. Sample 4 had the highest value while sample 1 had the lowest. The value showed significant difference p<0.05. Texture ranged from 6.1±1.1 to 4.10±1.3 for sample 4 and 6 respectively .It showed no significant difference at p<0.05. It ranged from 6.31±1.8 for sample 8 and sample 6 respectively. The overall appearance ranged from 6.31±1.8 for sample 8 and 4.10±1.2 for sample 6.It did not differ significantly at p< 0.05. This is in contrast with Kolawole et al (2009) When the overall acceptance and appearance differed significantly (p<0.05). However, the result is in line with Olapode et al ,. (2014) .

Conclusion

From this work it could be concluded that cassava products have appreciable level of microbial load. However, both the white and yellow varieties are similar as they showed no much difference in their E.N. Onyeneke et al. 267 microbial content. Again, the white variety showed higher overall acceptability values in almost all the samples and relatively higher in the total microbial count in all the samples.

Recommendation

It is recommended here that cassava products has significant level of microbial load hence there is need for proper sanitary condition and best processing and production to avoid health risk among its consumers as the cassava product especially garri forms the basic staple food in Nigeria and some African countries (IITA 1990).

Acknowledgements

My heartfelt thanks to the organizers of the International conference of arts and sciences at London University, 2016 for the opportunity because it’s not just a conference but also a forum for learning and sharing scientific ideas with academics and professionals. I am very grateful to Prof. C.N. Ubbaonu and Prof N.C.Ohazurike whose support and exposure made this research a real life experience. My gratitude goes my colleagues Dr Mrs Afam- Anene, Prof Asinobi, Dr Obiakor, P.N, Dr Mrs J.C. Nwaiwu, Dr Ogbuehi, Dr Mrs Nneka mark, Mrs Jessicca, Dr Newton Amaglo, Dr Ikpeama for all their encouragement during the research. I want to appreciate all the staff of the institute of Imo Agricultural Development Project and the staff of Imo state university, department of Food Science laboratory for the analysis of all data obtained from this research. My gratitude to my lovely husband Mr Onyeneke, O.B and my kids; Nelly, Nuela , Nelson and Neri for all their understanding and encouragement throughout the research period. I also recognize and appreciate the support of my other family members; Ezinne J.A Oke, Rev Obi Oke, Mr Emma Oke, Mrs Chika Ekwugha, Mrs Miriam Uwaga and Mrs Obianuju Uchendu. To God, I say a big thank you for making all things possible at His own time!

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