Download the complete microbiology project topic and material (chapter 1-5) titled MICROBIOLOGICAL QUALITY OF INDUSTRIALLY PROCESSED ORANGE FRUIT JUICES here on PROJECTS.ng. See below for the abstract, table of contents, list of figures, list of tables, list of appendices, list of abbreviations and chapter one. Click the DOWNLOAD NOW button to get the complete project work instantly.
The Project File Details
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:
1.2 LITERATURE REVIEW:
1.2.1 BACK GROUND STUDY OF ORANGE FRUIT JUICE
Orange juice is defined in the United States Code of Federal Regulations as the “unfermented juice obtained from mature oranges of the species Citrus sinensis or of the citrus hybrid commonly called Ambersweet.” True fresh squeezed juice is difficult to market commercially because it requires special processing to preserve it. Orange juice is commonly marketed in three forms: as a frozen concentrate, which is diluted with water after purchase; as a reconstituted liquid, which has been concentrated and then diluted prior to sale; or as a single strength, unconcentrated beverage called NFC or Not From Concentrate (Randy, 1997). The latter two types are also known as Ready To Drink (RTD) juices. Citrus fruits, like oranges, have been cultivated for the last 4,000 years in southern China and Southeast Asia. One variety, the citron, was carried to the Middle East some-time between 400 and 600 B.C. Arab traders transported oranges to eastern Africa and the Middle East sometime between 100 and 700 A.D. , and during the Arab occupation of Spain, citrus fruits first arrived in southern Europe (Nelson et al, 2000). From there, they were carried to the New World by explorers where they spread to Florida and Brazil by the sixteenth century. By the 1800s, citrus fruits achieved worldwide distribution. In the 1890s, the demand for them greatly increased because physicians discovered that drinking the juice of oranges or other citrus fruits could prevent scurvy, a vitamin deficiency disease. The popularity of orange juice dramatically increased again with the development of the commercial orange juice industry in the late 1920s. In its early days, the juice industry primarily relied on salvaged fruit, which was unsuitable for regular consumption because it was misshapen, badly colored or blemished. In the 1930s, development of porcelain-lined cans and advances in pasteurization techniques led to improved juice quality and the industry expanded significantly. Then, in 1944, scientists found a way to concentrate fruit juice in a vacuum and freeze it without destroying the flavor or vitamin content. Frozen concentrated juices were first sold in the United States during 1945-46, and they became widely available and popular. After World War II, most Americans stopped squeezing their own juice and concentrated juice became the predominant form. With the increase in home refrigerators, frozen concentrate became even more popular. The demand for frozen juices had a profound impact on the citrus industry and spurred the growth of the Florida citrus groves. Frozen concentrates remained the most popular form until 1985 when reconstituted and NFC juices first out-sold the frozen type. In 1995, NFC juices were responsible for 37% of the North American market. This is in comparison to reconstituted juice, which held about 39% of the market. Today, commercial aseptic packaging allows RTD juices to be marketed without refrigerated storage. The current worldwide market for orange juice is more than $2.3 billion with the biggest area being the United States followed by Canada, Western Europe, and Japan (Nelson et al, 2000).
1.2.2 RAW MATERIALS
The primary ingredient in orange juice is, of course, oranges. Oranges are members of the rue family (Rutaceae), and citrus trees belong to the genus Citrus. Oranges, along with all citrus fruits, are a special type of berry botanists refer to as a hesperidium. Popular types of oranges include navel, Mandarin, and Valencia. A blend of different types of oranges is generally used to provide a specific flavor and to ensure freedom from bitterness (Randy, 1997). Selection of oranges for juice is made on the basis of a number of factors such as variety and maturity of the fruit. The fruit contains a number of natural materials that contribute to the overall flavor and consistency of the juice including water, sugars (primarily sucrose, fructose, and glucose), organic acids (primarily citric, malic, and tartaric), and flavor compounds (including various esters, alcohols, ketones, lactones, and hydrocarbons) (Randy, 2006).
Preservatives such as sulfur dioxide or sodium benzoate are allowed by federal regulation in orange juice although the amounts are strictly controlled. Similarly, ascorbic acid, alpha tocopherol, EDTA, BHA, or BHT are used as antioxidants. Sweeteners may be added in the form of corn syrup, dextrose, honey, or even artificial sweeteners. More often, though, citric acid is added to provide tartness (Nelson et al., 2000)
Manufacturers may also fortify juices with extra vitamins or supplemental nutrients such as vitamin C, and less commonly, vitamins A and E, and beta carotene . (Beta carotene is naturally present in oranges, but only to a small degree.) There is some concern about the stability of these added vitamins because thehy do not survive the heating process very well. Calcium in the form of tricalcium phosphate is also frequently added to orange juice (Randy, 1997).
1.2.3 THE MANUFACTURING PROCESS
Oranges are harvested from large groves. Some citrus growers are members of cooperative packing and marketing associations, while others are independent growers. When the mature fruit is ready to pick, a crew of pickers is sent in to pull the fruit off the trees. The collected fruit is sent to packing centers where it is boxed for sale as whole fruit, or sent to plants for juice processing. The oranges are generally shipped via truck to juice extraction facilities, where they are unloaded by a gravity feed onto a conveyor belt that transports the fruit to a storage bin (Nelson et al., 2000).
The fruit must be inspected and graded before it can be used. An inspector takes a 39.7 lb (18 kg) sample to analyze in order to make sure the fruit meets maturity requirements for processing. The certified fruit is then transported along a conveyor belt where it is washed with a detergent as it passes over roller brushes. This process removes debris and dirt and reduces the number of microbes. The fruit is rinsed and dried. Graders remove bad fruit as it passes over the rollers and the remaining quality pieces are automatically segregated by size prior to extraction. Proper size is critical for the extraction process (Nelson et al., 2000).
Proper juice extraction is important to optimize the efficiency of the juice production process as well as the quality of the finished drink (Nelson et al., 2000). The latter is true because oranges have thick peels, which contain bitter resins that must be carefully separated to avoid tainting the sweeter juice. There are two automated extraction methods commonly used by the industry. The first places the fruit between two metal cups with sharpened metal tubes at their base. The upper cup descends and the fingers on each cup mesh to express the juice as the tubes cut holes in the top and bottom of the fruit. The fruit solids are compressed into the bottom tube between the two plugs of peel while the juice is forced out through perforations in the tube wall. At the same time, a water spray washes away the oil from the peel. This oil is reclaimed for later use (Randy, 1997). The second type of extraction has the oranges cut in half before the juice is removed. The fruits are sliced as they pass by a stationary knife and the halves are then picked up by rubber suction cups and moved against plastic serrated reamers. The rotating reamers express the juice as the orange halves travel around the conveyor line. When the mature fruit is ready to pick, a crew of pickers pull the fruit off the trees. Once collected, the fruit is sent to plants for juice processing. Before extraction, the fruit is cleaned and graded. Some of the peel oil may be removed prior to extraction by needles which prick the skin, thereby releasing the oil which is washed away (Nelson et al., 2000). Modern extraction equipment of this type can slice, ream, and eject a peel in about 3 seconds. The extracted juice is filtered through a stainless steel screen before it is ready for the next stage. At this point, the juice can be chilled or concentrated if it is intended for a reconstituted beverage. If a NFC type, it may be pasteurized (Randy, 1997).
Concentrated juice extract is approximately five times more concentrated than squeezed juice. Diluted with water, it is used to make frozen juice and many RTD beverages. Concentration is useful because it extends the shelf life of the juice and makes storage and shipping more economical (Randy, 1996). Juice is commonly concentrated with a piece of equipment known as a Thermally Accelerated Short-Time Evaporator, or TASTE for short. TASTE uses steam to heat the juice under vacuum and force water to be evaporated. Concentrated juice is discharged to a vacuum flash cooler, which reduces the product temperature to about 55.4° F (13° C). A newer concentration process requires minimal heat treatment and is used commercially in Japan. The pulp is separated from the juice by ultra-filtration and pasteurized. The clarified juice containing the volatile flavorings is concentrated at 50° F (10° C) by reverse osmosis and the concentrate and the pulp are recombined to produce the appropriate juice concentration. The flavor of this concentrate has been judged to be superior to what is commercially available in the United States and is close to fresh juice. Juice concentrate is then stored in refrigerated stainless steel bulk tanks until is ready to be packaged or reconstituted (Randy, 1997).
When the juice processor is ready to prepare a commercial package for retail sale, concentrate is pulled from several storage batches and blended with water to achieve the desired sugar to acid ratio, color, and flavor. This step must be carefully controlled because during the concentration process much of the juice’s flavor may be lost. Proper blending of juice concentrate and other flavor fractions is necessary to ensure the final juice product achieves a high quality flavor (Nelson et al., 2000)
Thanks to its low pH (about 4) orange juice has some natural protection from microbes. However, pasteurization is still required to further retard spoilage. Pasteurization also inactivates certain enzymes which cause the pulp to separate from the juice, resulting in an aesthetically undesirably beverage. This enzyme related clarification is one of the reasons why fresh squeezed juice has a shelf life of only a few hours (ICMSF, 2005). Flash pasteurization minimizes flavor changes from heat treatment and is recommended for premium quality products. Several pasteurization methods are commercially used. One common method passes juice through a tube next to a plate heat exchanger, so the juice is heated without direct contact with the heating surface. Another method uses hot, pasteurized juice to preheat incoming unpasteurized juice. The preheated juice is further heated with steam or hot water to the pasteurization temperature. Typically, reaching a temperature of 185-201.2° F (85-94° C) for about 30 seconds is adequate to reduce the microbe count and prepare the juice for filling (Randy, 1997).
To ensure sterility, the pasteurized juice should be filled while still hot. Where possible, metal or glass bottles and cans can be preheated (Randy 1997). Packaging which cannot withstand high temperatures (e.g., aseptic, multilayer plastic juice boxes which don’t require refrigeration) must be filled in a sterile environment. Instead of heat, hydrogen peroxide or another approved sterilizing agent may be used prior to filling. In any case, the empty packages are fed down a conveyor belt to liquid filling machinery, which is fed juice from bulk storage tanks. The filling head meters the precise amount of product into the container, and depending on the design of the package, it may immediately invert to sterilize the lid. After filling, the containers are cooled as fast as possible. Orange juice packaged in this manner has a shelf life of 6-8 months at room temperature (Nelson et al., 2000).
Byproducts from orange juice production come from the rind and pulp that is created as waste. Products made with these materials include dehydrated feed for livestock, pectin for use in making jellies, citric acid, essential oils, molasses, and candied peel. Certain fractions of orange oil (known as d-limonene), have excellent solvent properties and are sold for use in industrial cleaners (Randy, 1997).
1.2.5 Quality Control
Quality is checked throughout the production process. Inspectors grade the fruit before the juice is extracted. After extraction and concentration, the product is checked to ensure it meets a number of USDA quality control standards (ICMSF, 2005). The most important measurement in orange juice production is the sugar level, which is measured in degrees Brix (percentages by weight of sugar in a solution) (Randy, 1996). The types of oranges used and the climate in which they were grown affect the sugar level. Manufacturers blend juices with different sugar levels together to achieve a desired sugar balance. The final juice product is evaluated for a number of key parameters include acidity, citrus oil level, pulp level, pulp cell integrity, color, viscosity, microbiological contamination, mouth feel, and taste. A sensory panel is used to evaluate subjective qualities like flavor and texture. Lastly during the filling process, units are inspected to make sure they are filled and sealed appropriately (Nelson et al., 2000).
1.2.6 The Future
Future processing improvements are likely to come from the use of computer controlled sizing and grading of fruit. Orange juice formulations will see changes as the trend toward adding more nutrition-oriented ingredients, such as antioxidants, continues. In addition, future formulas are likely to be blends of orange juice with other, more exotic, fruit flavors, like kiwi, or even vegetable juices, like carrot (Randy, 1997).
1.3 PATHOGEN ASSOCIATED WITH ORANG JUICE
Food borne diseases are an increasingly recognized problem involving a wide spectrum of illnesses caused by bacterial, viral, parasitic or chemical contamination of food. Although viruses account for half of all the food borne illnesses, most hospitalizations and deaths related to food borne infections are due to bacterial agents. Diarrheal diseases are the commonest manifestation of food poisoning and in some cases, can lead to death. The diseases are caused by either toxin from the “disease-causing” microbe, or by the human body’s reactions to the microbe itself (Teplitski et al., 2009). The spoilage of fruit juice occurs, if the fruit is untreated, in a matter of hours or days and results in the juice becoming unappetizing, poisonous or infectious. Spoilage is caused by the practically unavoidable infection and subsequent decomposition of juice by bacteria and fungi, which are borne by the fruit itself, by the people handling the fruits, and by their implements. Fruit juice can be kept drinkable for a much longer time if proper hygiene is observed during production and processing, and if appropriate food safety, food preservation and food storage procedures are applied.
Bacterial genera commonly infecting orange juice while it is being processed, cut, packaged, transported, sold and handled include; Escherichia coli, Staph .aureus and Salmonella. These bacteria are all commonly carried by humans (Lawrie et al., 2006). As these microorganisms colonize the fruit juice, they begin to break it down, leaving behind toxins that can cause enteritis or food poisoning, potentially lethal in the rare case of botulism (Lawrie et al., 2006).The microorganisms do not survive heating, but several of their toxins and microbial spores do (Lawrie et al., 2006). The microbes may also infect the person drinking the fruit juice, although against this the microflora of the human gut is normally an effective barrier (Lawrie et al., 2006).
1.4 HEALTH IMPLICATION OF CONTAMINATED ORANGE FRUIT JUICE
Food borne diseases are diseases resulting from ingestion of bacteria, toxins and cells produced by microorganism present in food. Food borne illness is a major international health problem with a consequent economic reduction. Important bacteria food borne pathogen may be implicated either of the two primary types of food released diseases: food borne ingestion and food intoxications.
A food borne ingestion involves the ingestion of pathogen, followed by growth in the host, including invasion and or the release of toxin (Prescott et al., 2008).
Some of the major diseases of this type associated with fruit product include listeriosis and hemorrhagic colitis caused by a strain of Escherichia coli known as Enterohemorrhagic Escherichia coli (Dolobes et al., 2011).
Food intoxication produces a symptom after food is consumed because of the growth of the disease causing microorganisms (bacteria) is not required (Prescott et al., 2008). Major diseases of this type associated with orange juice include staphylococcal food intoxication.
In most countries the most common food borne illness is Staphylococcus food intoxication. Enterotoxigenic Staphylococcus strains and E.coli strains have been so latent from food implicated to illness. E. coli and S. aureus are named flora in humans and animals. Their presence in food is an indication of excessive human handling. They produce some enzymes which are very harmful and extra cellular substances some of which are heat stable enterotoxin that render food dangerous even though it appears normal (Prescott et al., 2008).
Once the bacteria has produced toxin, the food can be extensively and properly cooked killing the bacterial without destroying their toxin. Many of the toxin are gene based that is carried on plasmid. The intensity of the sign and symptoms may vary with amount of contaminated food ingested and susceptibility of individual to toxins. Escherichia coli are commonly used as a surrogate indicator. Its presences in food (orange juice) generally indicate direct or indirect food combination.
In the health benefit of Orange juice, you can get healthy significance because the orange contains a lot of dietary fibers that prevent constipation and also reduces cholesterol.
1.5 POSSIBLE BACTERIA THAT CAN BE FOUND IN ORANGE FRUIT JUICE
Man’s respiratory passages, skin and superficial wounds are common sources of S. aureu. When S. aureus is allowed to grow in juice, it can produce a toxin that causes illness. Although heating destroys the bacteria, the toxin produced is heat stable and may not be destroyed. Staphylococcal food poisoning occurs most often in foods that require hand preparation, such as potato salad, ham salad and sandwich spreads and fruit juice. Sometimes these foods and drinks are left at room temperature for long periods of time, allowing the bacteria to grow and produce toxin. Good hygiene while handling and preparation of food and drinks will help keep S. aureus out of foods, and refrigeration of fruit drinks, raw and cooked foods will prevent the growth of these bacteria if any are present (Wagner, 2008).
A rapid onset which is usually 1–8 hours, nausea, explosive vomiting for up to 24 hours, abdominal cramps/pain, headache, weakness, diarrhea and usually a subnormal body temperature. Symptoms usually start one to six hours after ingestion and last less than 12 hours. The duration of some cases may take two or more days to fully resolve (Prescott et al., 2008).
The gastrointestinal tracts of animals and man are common sources of Salmonella. High protein foods such as meat, poultry, fish and eggs are most commonly associated with Salmonella, although poor hygiene in industries, where food and drinks are produced, can introduce the bacteria into the products. However, any food that becomes contaminated and is then held at improper temperatures can cause salmonellosis. Salmonella are destroyed at temperatures above 150 degrees F. The major causes of salmonellosis are contamination of foods/ drinks and insufficient heating. Contamination of foods/drinks occurs from contact with surfaces of utensils that were not properly washed after use with raw products. If Salmonella is present on foods, its growth can be controlled by refrigeration below 40 degrees F (Wagner, 2008).
Enteropathoginec E. coli is a significant cause of diarrhea in developing countries and localities of poor sanitation. There are at least four subgroups of enteropathogenic E. coli: enterotoxigenic, enterinvasive, hemorrhagic, and enteropathogenic. Each strain has different characteristics. The major source of the bacteria in the environment is probably the feces of infected humans, but there may also be animal reservoirs. Feces and untreated water are the most likely sources for contamination of food. Control of enteropathogenic E. coli and other food-borne pathogens such as Salmonella and Staphylococcus aureus can be achieved.
Food and drink service establishments should monitor adequacy of heating, holding times, and temperatures as well as the personal hygiene of handlers (Wagner, 2008).
Symptoms of intestinal infection include diarrhea, abdominal pain, and fever. More severe cases can lead to bloody diarrhea, dehydration, or even kidney failure. People with weakened immune systems, pregnant women, young children, and older adults are at increased risk for developing these complications.
Most intestinal infections are caused by contaminated food or water. Proper food preparation and good hygiene can greatly decrease your chances of developing an intestinal infection. Most cases of intestinal E. coli infection can be treated at home (Prescott et al., 2008)