Equity Journal of Science and Technology, 2019 6(1): 72 -77 ISSN; 2354 – 1814 EQUIJOST An Official Publication of Kebbi State University of Science and Technology, Aliero, Nigeria Evaluation of Fungi Species from Commercial Yoghurts in Birnin Kebbi, Kebbi State Nigeria *1Keta, J.N., 2Suberu, H.A., 3Aliero, A.A., 4Mohammed, N.K., 1Anas, H., 1Mubarak, A. 1Department of Plant Sciences and Biotechnology, Kebbi State University of Science and Technology, Aliero, Nigeria 2Department of Biological Science, Federal University, Lokoja, Kogi State, Nigeria 3Department of Biological Science Federal University, Kalgo, Kebbi State, Nigeria 4Department of Microbiology, Kebbi State University of Science and Technology, Aliero *Corresponding author Email; [email protected]; Abstract Yoghurt is frequently taken as a drink or prepared together with Fura in the northern part of Nigeria due to the quality of nutrients present. Five different commercial Yoghurts, namely Hamdala, Rufaida, Gamji, Alhilal and Batulah were purchased from distributors in Birnin Kebbi metropolis. Using culture growth medium (Potato dextrose Agar) and poured plate method, the fungi species present were analyzed. A total of five (5) fungal species were isolated and identified from the samples. These include Aspergillus niger, Aspergillus fumigatus, Penicillium, Fusarium species and Mucor species. The results obtained from the samples analyzed showed that the Yoghurts samples had fungal load in the range of 1.2 x 105 (as the lowest fungal count in Gamji and Hamdala Yoghurts) and 8.0 x 106 (as the highest fungal count in Batula, Alhalal and Rufaida yoghurts). The highest levels of fungal species identified from this study could be attributed to poor processing method, environment, equipment used and preservation method adopted by these industries. Thus, there is need for these Yoghurts industries to improve on the quality of their products by improving their processing method, proper hygienic environment, personnel as well as proper storing method. Keywords: Fungi, Commercial Yoghurt, Birnin Kebbi 1. Introduction increased their nutritional qualities, which make it to have the same value as fresh milk [2]. Yogurt is a product of fermented milk that resulted from the need to prolong the shelf life Yoghurt is made from milk, which is known for to prevent milk spoilage [1]. However, not until ages. It is a custard-like food with a sour flavor in the 20th century when Yoghurt became a that is prepared from milk curdled by bacteria profitable commercially good product, Yoghurt such as Lactobacillus bulgaricus and manufacturers were not giving standards for its Streptococcus thermophilus that make it to have production. This however, have raised the value the same test and flavor as fruit [3]. The L. of Yoghurt products worldwide and also bulgaricus produces amino acids, which stimulate S. thermophilus to produce formic 72 Keta, J.N. et al.: Evaluation of Fungi Species from Commercial Yoghurts in Birnin Kebbi, Kebbi State Nigeria acid. The presences of S. thermophilus revolve Yogurt could be contaminated with different the milk sour and produce a distinctive, typical microbial organisms among which the pleasant smell. Yoghurt can be produce using dominant ones are the molds or fungi. Some of animal milk depending on the resources these could be pathogenic in nature and some available and geographical location of the could cause spoilage of the product due to their industries as well as the consumer preferences metabolic activities on the specific products. [4]. Other substances apart from milk that are However, the unhygienic nature of preparation added during manufacturing of Yoghurt and production method, post production contribute in determining the state of the processes, environmental conditions Yoghurt condition [5]. surrounding the production and storage conditions are all necessary for the spoilage of Yoghurt is said to be low in saturated fatty acids Yoghurt products [11, 12]. Molds and yeast are and cholesterol level, but is nutritionally rich in the primary contaminants in Yoghurts produced protein and vitamins such as, calcium, iron, in Nigeria and other countries [13]. These potassium, and phosphorus, which maintain the microorganisms as they grow in Yoghurt, Red blood cells, improve the good function of utilize some of the acid present and cause a the nervous system in human body [6]. Yoghurt corresponding decrease in the acidity of the is said to prevent high blood pressure in Yoghurt, which may favor the growth of hypertensive people. The percentage of putrefactive organisms in the product. potassium in Yoghurt is higher having 600 mg Therefore, this research study aimed at per bottle container of Yoghurt, and these assessing and identifying the different fungal would help to flush the excess sodium and iron species responsible for the spoilage of Yoghurt out of the human metabolic system when taken products in the study area. and could also help in maintaining the normal activities or metabolic activities in the human 2. Materials and Methods body system [11]. The proteins, carbohydrate 2.1 Sample Collection and Serial Dilution and vitamins contents present in Yoghurt are found to be greater compared to those in fresh Yoghurt samples were collected from five (5) milk [7, 8]. However, there is little difference different Yoghurt companies in Birnin Kebbi between fresh milk and Yoghurt product in metropolis. From each company, five (5) terms of energy and sugar contents. This is to Yoghurt samples, packaged in plastic bottles, say that the sweeter Yoghurt provides more were collected to make a total of twenty-five energy when compared to fresh milk [9]. (25) samples. The five (5) Yoghurt product companies selected within Birnin Kebbi for the According to our research source, there are two sample collection were Gamji, Alhalil, Rufaida, types of commercially prepared Yoghurts Batulah and Hamdala. The samples collected produced in Birnin Kebbi metropolis. These were brought to the Department of Plant are: the powdered Yoghurt and the soft or liquid Science and Biotechnology, Kebbi State yoghurt. But the most commonly produced type University of Science and Technology, Aliero in Birnin Kebbi metropolis is the soft Yoghurt and the samples were kept refrigerated for one [10]. However, in Northern Nigeria Yoghurt is day before serial dilution. Two grams (2 g) of a very important product of “Fura” delicacy each sample was measured and added to a which gives Yoghurt its paramount importance conical flask containing 9 ml of distilled water as many people now prefer Yoghurt with Fura from which serial dilution was carried out up to than as it was originally known to be taken with seven places as describe previously [13]. fresh cow milk. 2.2 Culture media preparation 73 Keta, J.N. et al.: Evaluation of Fungi Species from Commercial Yoghurts in Birnin Kebbi, Kebbi State Nigeria Potato Dextrose Agar (PDA) was used to result showed higher fungal load in Yoghurt culture the organisms. The medium was samples obtained from Alhalil, Rufaida and prepared according to the manufacturer’s Batulah Yoghurt companies (8.0 x 105 – 8.0 x instructions. The prepared media were allowed 106 colony). While Hamdala and Gamji to cool down over night before being poured Yoghurts had lowest fungal load (1.6 x 10 and into petri dish plates, which were then 1.2 x 105). incubated at 28 oC for 3-5 days. After five days, fungal growth was observed on the petri dish Table 3.1: Total Fungi count of five samples and the same method was used to sub cultured in replicates the fungal myclia on fresh medium in other to Colony Form No. of obtained pure culture the isolated [14]. Sample Name Per Unit Colony (CFU/g) 2.3 Fungi Identification Gamji Yoghurt 4 4.0×106 The fungi were identified using morphological Gamji Yoghurt 12 1.2×105 and cultural characteristics, type of fruiting 4 structure and spores produced and also, by Gamji Yoghurt 4 4.0×10 making comparison with mycological atlas. Hamdalah 16 1.6×106 The technique of [15,16] was adopted for Yoghurt identification of the unknown isolated fungi Hamdalah 4 4.0×105 using cotton blue in lacto phenol stain. The Yoghurt slides were mounted and observed with x10 and Hamdalah 4 4.0×104 x40 objective lenses respectively [16]. Yoghurt 6 Statistical analysis was done based on the Batullah Yoghurt 8 8.0×10 colony formation unit per gram (Cfu/g). 5 Batullah Yoghurt 8 8.0×10 4 3. Results and Discussion Batullah Yoghurt 20 2.0×10 6 3.1 Results Alhalal Yoghurt 8 8.0×10 5 Alhalal Yoghurt 8 8.0×10 The results of the fungal load obtained and 4 analyzed from the five (5) Yoghurt companies, Alhalal Yoghurt 16 1.6×10 namely Gamji, Alhalil, Rufaida, Batulah and Rufaida Yoghurt 8 8.0×106 Hamdala are shown in Table 3.1. The Rufaida Yoghurt 8 8.0×105 morphological and microscopic features of the Rufaida Yoghurt 16 1.6×104 fungal isolates are shown in Table 3.2. The 74 Keta, J.N. et al.: Evaluation of Fungi Species from Commercial Yoghurts in Birnin Kebbi, Kebbi State Nigeria Table 3.2: Morphological and microscopic features of the isolated fungi species Colony Appearance Microscopic Examination Mold Species Colonies were green and Septate hypha formed with smooth walled Penicillium velvety. The reverse side conidiosphore bearing long chains of species was pale yellow in color conidia. Colonies were green Sporangia are back and zygospores and Mucor species sporangio sphores were long branched hyphae were of septate White, later becoming black Septate hyphae with simple thick walls. Aspergillus niger and some pale yellow Conidiosphores bearing conidial head containing conidian was seen Colonies were commonly Conidiosphores are short, smooth walled Aspergillus blue green with narrow bearing conical shaped terminal vesicles fumigates white borders Colonies are usually fast- Multi celled sicked from macro conidia Fusarium species growing pale or bright in seen colour 3.2 Discussion Aspergillus niger and Fusarium species from Yoghurt samples were also reported.