KWAME NKRUMAH UNIVERSITY OF SCIENCE AND TECHNOLOGY COLLEGE OF SCIENCE FACULTY OF BIOSCIENCES DEPARTMENT OF FOOD SCIENCE WATER ACTIVITY PROFILE AND MICROBIAL SAFETY OF HOT PEPPER SAUCE “SHITO” BY GLORIA ASAFO-ADJAYE NOVEMBER, 2018 1 WATER ACTIVITY PROFILE AND MICROBIAL SAFETY OF HOT PEPPER SAUCE “SHITO” By GLORIA ASAFO-ADJAYE (BSc Catering and Hospitality Education) A thesis submitted to the Department of Geography, Kwame Nkrumah University of Science and Technology, Kumasi in partial fulfilment of the requirements for the award of MASTER OF SCIENCE IN FOOD QUALITY MANAGEMENT NOVEMBER, 2018 2 DECLARATION/ CERTIFICATION I hereby declare that this submission is my own work and that, to the best of my knowledge and belief, it contains no material previously published or written by another person nor material which to a substantial extent has been accepted for the award of any other degree or diploma at Kwame Nkrumah University of Science and Technology, Kumasi or any other educational institution, except where due acknowledgment is made in the thesis. GLORIA ASAFO-ADJAYE (PG1048517) ............................. ............................ Student Name and ID Signature Date Certified by Supervisors: Dr.(Mrs). Gloria Ankar-Brewoo ............................. ............................. Signature Date Certified by Dr Faustina Dufie Wireko-Manu. ............................. ............................. Head of Department: Signature Date ii ABSTRACT Hot pepper sauce “shito” is one of the commonly used products in most Ghanaian homes, schools, restaurants etc, which sometimes serves as condiments. This study therefore seeks to determine the water activity profile and microbial safety of hot pepper sauce „shito‟. “Shito” samples were purchased in the Kumasi Metropolis from Food and Drugs Authority registered and non-registered manufacturers. Water Activity and microbial contamination were determined using standard methods. Water Activity (aw) for the results for FDA registered products were between 0.51 and 0.88 while those for product not registered with the FDA were between 0.52 and 0.95. FDA Registered shito samples recorded a significant difference lower total aerobic count (23%) as compared to unregistered samples (46%). The morphological characterization on the agar plates indicated the presence of Escherichia coli. and some suspected Enterococci faecalis spp. However, no Salmonellaspp. was detected in the samples. A direct correlation was found between total aerobic count and coliform assay for samples, which failed the TAC assay. The presence of E.coli indicated the poor personal hygiene of the some of the shito manufacturers. “Shito” produced by FDA registered caterers are safer and might have longer shelf life due to their lower aw and microbial load as compared to non-FDA registered caterers. iii ACKNOWLEDGEMENT To God be the Glory great things He has done. For without him this study would not be a success. With unqualified appreciation, I say thank you Dr. Gloria Ankar-Brewoo for the continuous support and encouragement throughout the entire study. May God never cease to bless you, lastly, I say thank you to my husband Michael Asafo-Adjaye and my children for your lovely, care and support. Thank you all once again. iv TABLE OF CONTENT DECLARATION/ CERTIFICATION...................................................................... II ABSTRACT............................................................................................................... III ACKNOWLEDGEMENT ....................................................................................... IV TABLE OF CONTENT ............................................................................................. V LIST OF TABLES ................................................................................................. VIII LIST OF FIGURES .................................................................................................. IX LIST OF PLATE ........................................................................................................ X CHAPTER ONE .......................................................................................................... 1 INTRODUCTION ....................................................................................................... 1 1.1 BACKGROUND OF THE STUDY ........................................................................ 1 1.2 STATEMENT OF THE PROBLEM ......................................................................................... 4 1.3 OBJECTIVE ............................................................................................................ 4 1.4 SIGNIFICANCE OF THE STUDY ........................................................................ 4 1.5 LIMITATIONS OF THE STUDY .......................................................................... 5 CHAPTER TWO ......................................................................................................... 6 LITERATURE REVIEW ........................................................................................... 6 2.1 THE CONCEPT OF WATER ACTIVITY PROFILE ............................................ 6 2.2 THE IMPACT OF WATER ACTIVITY ON THE SHELF LIFE OR STABILITY OF FOODS .................................................................................................................... 7 2.3 THE ROLE OF WATER ACTIVITY IN ENSURING QUALITY AND FOOD SAFETY ........................................................................................................................ 8 2.4 FACTORS THAT INFLUENCE MICROBIAL SAFETY IN FOOD PRODUCTS9 2.4.1 MICRO OR INTERNAL FACTORS ................................................................... 9 2.4.2 MACRO OR EXTERNAL FACTORS .............................................................. 11 2.5 MICROORGANISMS IN FOOD .......................................................................... 13 2.5.1 MICROBIAL QUALITY OF CONDIMENTS .................................................. 15 2.6 THE CONCEPT OF HOT PEPPER SAUCE „SHITO‟ ........................................ 15 2.7 MICROBIAL LOAD OF FOODS SOLD IN SHOPS AND ON STREETS IN GHANA ....................................................................................................................... 15 v 2.8 SOURCES OF FOOD CONTAMINATION ........................................................ 16 CHAPTER THREE ................................................................................................... 17 METHODOLOGY .................................................................................................... 17 3.1 MATERIALS ........................................................................................................ 17 3.2 SOURCE OF SAMPLE ......................................................................................... 17 3.1 WATER ACTIVITY DETERMINATION ........................................................... 17 3.2 SAMPLE PREPARATION ................................................................................... 18 3.3.1 PREPARATION OF PLATE COUNT AGAR .................................................. 18 3.3.2 PREPARATION OF MANNITOL SALT AGAR ............................................. 19 3.3.3 PREPARATION OF MACCONKEY AGAR.................................................... 19 3.4 SERIAL DILUTION ............................................................................................. 19 3.5 DETERMINATION OF TOTAL AEROBIC COUNT ......................................... 19 3.5.1 SUB-CULTURING ............................................................................................ 20 3.6 BIOCHEMICAL TESTS ....................................................................................... 20 3.6.1 CATALASE TEST ............................................................................................. 20 3.6.2 CITRATE UTILIZATION TEST ....................................................................... 21 3.6.3 GRAM STAINING AND MICROSCOPY ........................................................ 21 3.7 DETERMINATION OF STAPHYLOCOCCUS AUREUS ................................. 21 3.8 DETERMINATION OF TOTAL COLIFORM COUNT ...................................... 22 3.9 DATA ANALYSIS ............................................................................................... 22 CHAPTER FOUR ..................................................................................................... 23 RESULTS AND DISCUSSION ................................................................................ 23 4.1 WATER ACTIVITY ............................................................................................. 23 4.2 MICROBIAL LEVEL OF „SHITO‟ SAMPLES ................................................... 24 4.2.1 TOTAL AEROBIC COUNT (TAC) .................................................................. 24 4.2.3 QUALITATIVE ASSESSMENT OF COLIFORMS ......................................... 30 4.3 QUALITATIVE ASSESSMENT OF MICROBIAL QUALITY OF SAMPLES 32 4.3.1 STAPHYLOCOCCUS SPECIES ....................................................................... 32 vi CHAPTER FIVE ....................................................................................................... 35 CONCLUSION AND RECOMMENDATION ....................................................... 35 5.1 CONCLUSION...................................................................................................... 35 5.2 RECOMMENDATION ........................................................................................