Species Of Fungi Associated With Deteriorated Loaves Of Bread

ABSTRACTStudies were carried out on species of fungi associated with deteriorated loaves of bread. Ten (10) loaves of bread each weighing 10kg each were purchased from different shops in local market within Umuahia metropolis in the morning and evening. A total of thirty seven (37) fungi species were isolated using the pour plate technique. The fungal isolates included; Aspergillus niger, Fusarium oxysporum, Aspergillus flavus, Rhizopus stolonifer, Mucor alternaria and Rhodotorula spp, which were responsible for the bread spoilage. The results in this study revealed that after incubation period, the total fungal count of each bread samples over a storage period of fifteen (15) days ranged from 0.20x1011 to 6.95x1011. There was no fungal count on the first two days of study for the ten (10) bread samples used. The percentage of occurrence of the fungi in the bread samples showed that Rhodotorula spp 9(24.32%) had the highest percentage followed by Rhizopus stolonfer 7(18.92%) and Mucor alternaria 7(18.92%) while Aspergillius spp 4(10.8%) had the lowest frequency of occurrence. The percentage moisture content of the spoilt bread samples ranged from 43.2 to 43.7 while the pH values were between 4.90 and 4.98. Sample (C) had the highest percentage moisture content and least pH values of 43.7 and 4.90 respectively while Sample (B) and I had the lowest percentage moisture content at 43.2 each. The low pH of the samples may be due to the use of acidic chemical preservatives such as propionates, palmitates or sorbates in bread. High moisture content and low pH make bread susceptible to fungal spoilage. The knowledge of the fungal spoilage of bread will educate the consumers on the public health implications of the growth of the organisms and their toxins in bread and proffer the possible solutions to such spoilage. This study concluded that various fungi, especially Mucor spp and Rhodotorula spp are associated with spoilage of bread.
TABLE OF CONTENTSTitle ﾿        Page Title Page ﾿   ﾿ iCertification ﾿ iiDedication ﾿ iiiAcknowledgement ﾿ ivTable of Contents ﾿ vList of Tables ﾿ viiAbstract ﾿ ixCHAPTER ONE1.0 ﾿ Introduction ﾿ 11.1 ﾿ Aim and Objectives ﾿ 4CHAPTER TWO2.0 ﾿ Literature Review ﾿ 52.1 ﾿ Bread Production ﾿ 52.2.1 ﾿ Flour ﾿ 52.3 ﾿ Microorganisms Associated With Bread Spoilage ﾿ 62.3.1 ﾿ Penicillium spp ﾿ 62.3.2 ﾿ Mucor spp ﾿ 62.4 ﾿ Economical Importance of Bakery Products (Bread) ﾿ 72.5 ﾿ Microbial Spoilage of Bakery Products (Bread) ﾿ 82.5.1 ﾿ Bacterial spoilage ﾿ 92.5.2 ﾿ Yeast spoilage ﾿ 102.5.3 ﾿ Mold spoilage ﾿ 112.6 ﾿ Physical Factors Influence the Microbial Growth ﾿ 122.6.1 ﾿ Effect of Temperature, Ph and Water Activity ﾿ 122.7 ﾿ Control of Microbial Growth in Bakery Products (Bread) ﾿ 142.7.1 ﾿ Freezing ﾿ 152.7.2 ﾿ Preservatives ﾿ 152.8 ﾿ Effect of Chemical Preservatives ﾿ 152.8.1 ﾿ Sorbic Acid and Sorbates ﾿ 172.8.2 ﾿ Propionic Acids and Its Salts ﾿ 172.8.3 ﾿ Effect of Bio-preservatives ﾿ 18
CHAPTER THREE3.0 ﾿ Materials and Methods ﾿ 203.1 ﾿ Source/Collection of Samples ﾿ 203.1.1 ﾿ Materials and Media Used ﾿ 203.1.1 ﾿ Sterilization of Materials ﾿ 203.2 ﾿ Isolation of Fungi Associated With Bread Spoilage ﾿ 203.2.1 ﾿ Processing of Samples ﾿ 203.2.2 ﾿ Preparation of sample and inoculation of samples ﾿ ﾿ 213.2.3 ﾿ Isolation of Spoilage Fungi ﾿ 213.2.4 ﾿ Sub-culturing/Purification and Identification of Test Fungi Pathogens ﾿ 213.2.5 ﾿ Identification of Fungal Isolates ﾿ 223.2.5.1 ﾿ Wet Preparation ﾿ 223.2.5.2 ﾿ Colonial Morphology ﾿ 223.3 ﾿ Determination of Parameters at Which Bread Spoilage Occur ﾿ 223.3.1 ﾿ Determination of the Moisture Content of the Bread Samples ﾿ 223.3.2 ﾿ Determination of the pH of the Bread Samples ﾿ 233.3.3 ﾿ Determination of Percentage Occurrence of the Bread Samples ﾿ 23CHAPTER FOUR4.0 ﾿ Results ﾿ 244.1 ﾿ The Mean Fungal Counts in cfu/g of Bread Spoilage Samples ﾿ 244.2 ﾿ The Cultural Morphology and Microscopic Characteristics of Fungal  ﾿ Isolates from the Spoilt Bread Samples ﾿ 244.3 ﾿ The Percentage Moisture Content and pH of the Spoilt Bread Sample ﾿ 244.4 ﾿ The Percentage Occurrence of Various Fungi Isolates from Spoilt Bread Samples ﾿ 24CHAPTER FIVE5.0 ﾿ Discussion and Conclusion ﾿ 295.1 ﾿ Discussion ﾿ 295.2 ﾿ Conclusion ﾿ 31 ﾿ References