CHAPTER ONE
1.0 INTRODUCTION
Fruit juices are very nutritive, invigorating and non-alcoholic beverage, which is very well liked throughout the world. Juice may be squeezed directly from fruits or may be extracted by water. These juices can be used in their natural concentrations or in processed form. They are very scrumptious and palatable and they have most of the minerals necessary for growth and development, like calcium, magnesium, phosphorus, and sodium and vitamins especially vitamin C (Food and Drug Administration (FDA), 1999). However, these processed juices contain mainly water, sugar, preservatives, colour, fruits pulps and other additives as ingredients and must maintain sanitary standard (Doyle et al., 2001). The most commonly used preservatives are benzoic acid, sorbic acid, or sulphur dioxide (Nahar et al., 2006). Natural colours such as anthocynins and betanin are used (Wareing and Dvenport, 2005). Acid is an essential universal constitution of fruit drinks (Renard, 2008). The most commonly used acid is citric acid.
Fruit juices contain a microflora which is normally present on the surface of fruits during harvest and postharvest processing which include transport, storage, and processing (Tournas et al., 2006). Many microorganisms such as acid tolerant bacteria and fungi (moulds, yeasts) use them as a substrate for their growth. Yeasts form the main flora of fruits before processing because of acidic pH. The major genera include Candida, Dekkera, Hanseniaspora, Pichia, Saccharomyces, and Zygosaccharomyces. Penicillium, Byssochlamys, Aspergillus, Paecilomyces, Mucor, Cladosporium, Fusarium, Botrytis, Talaromyces, and Neosartorya are filamentous fungi most frequently isolated from fresh fruits and juices. Among bacteria, lactic acid bacteria and acetic acid bacteria have been isolated from fruit juices (International Commission on Microbiological Specification for Food (ICMSF), 2005).
Most fruit juices contain sufficient nutrients that could support microbial growth. Several factors encourage, prevent, or limit the growth of microorganisms in juices; the most important are pH, hygienic practice and storage temperature and concentration of preservative (Lawlor et al., 2009). Storage of products at refrigerator temperature or bellow is not always best for the maintenance of desirable quality of some fruits (Matchis, 2008). Water used for juice preparation can be a major source of microbial contaminants such as total coliforms, faecal coliforms, faecal streptococci and so on (Gill et al., 1996). Environmental fomites may also make the fruits unsafe and these may have a role in spreading of Salmonella, Shigella, Vibrio, Escherichia coli, and other diseases, as well as causing fruits spoilage (Doyle et al., 2001). Spoilage yeasts, such as Saccharomyces cerevisiae, Candida lipolytica and Zygosaccharomyces spp. can tolerate acidic environments (ICMSF, 2005). It should also be noted that changes in pH could transform a food into one which can support growth of pathogens (ICMSF, 2005). The critical factors affecting the spoilage of juices include juice pH, oxidation reduction potential, water activity, availability of nutrients, presence of antimicrobial compounds, and competing microflora. Among these factors, pH and water activity are the most influential factors affecting the spoilage of juices. The spoilage caused by microorganisms in juices includes cloud loss, development of off-flavours, CO2 production, and changes in colour, texture, and appearance resulting in degradation of product (Lawlor et al., 2009; Sospedra et al., 2012). The most commonly reported bacterial genera include Acetobacter, Alicyclobacillus, Bacillus, Gluconobacter, Lactobacillus, Leuconostoc, Zymomonas, and Zymobacter. Among yeasts Pichia, Candida, Saccharomyces, and Rhodotorula are commonly encountered genera responsible for spoilage of juices (Bevilacqua et al., 2011). Certain common moulds such as Penicillium sp., Aspergillus sp., Eurotium, Alternaria, Cladosporium, Paecilomyces, and Botrytis have also been reported in spoilage of fruit juices (ICMSF, 2005; Lawlor et al, 2009).
The quality of fruit drinks are strictly maintained, in developed countries like The United States, under some law and regulation but in many developing countries, like Nigeria and under developed countries, Libya for example, the manufacturer is not concerned about the microbiological safety and hygiene of the fruit Juice because of negligence of law. Thus the transmission of some human diseases through juice and other drinks are considered a serious problem in recent years (Geldreich and Bordner, 2000). The market for these products continues to show a remarkable potential for growth. The variety of products and packaging types continues to expand. In recent years these juices have been included significantly in diet of every person irrespective to age or social status. So maintaining the quality of processed fruit juices is an important issue now.
1.1 Aim and Objective:
- In order to develop awareness among the people about fruit juices in transmitting diseases this study was attempted to measure microbiological quality of industrially processed Orange fruit juices.
- This study aims at identifying the possible mediums through which contamination of fruit juice can occur and attempts to proffer possible ways of preventing these contaminations
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