STATEMENT OF RESEARCH PROBLEM:

Foodborne diseases are a major global problem causing considerable morbidity and mortality annually (Hanson et al.,
2012). World Health Organization (WHO) reported that every day more than 5000 children die globally due to consumption of contaminated food and water (Moeezuddin, 2005). Foodborne illnesses are prevalent in all parts of the world and their toll on human well-being is enormous which lead to major economic loss (Caroline et al., 2008). The incidence rate of foodborne diseases is also rising up. In industrialized countries about one third of the population is suffering from foodborne illnesses each year whereas, in developing world the problem is worse due to overcrowding, poverty, inadequate sanitary conditions and poor general hygiene (Fratamico et al., 2005). Ready-to-eat foods such as rice available in market have gained much popularity over the years because of the ease and the taste these offer. Despite of their advantages, the category ready-to-eat is considered as high-risk foods because they do not necessitate any heating or processing prior to consumption (Cruickshank, 1990).

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Diarrhoeal disease remains one of the most important causes of morbidity and mortality in developing countries, especially in African countries (Kosek et al., 2003). Worldwide, acute diarrhoea constitutes a major cause of morbidity and mortality, especially among the very young, very old, and infirm. It is estimated that each year, U.S. adults experience 99 million episodes of acute diarrhoea or gastroenteritis, resulting in about 8 million physician visits and more than 250,000 hospital admissions each year (1.5% of adult hospitalizations). Most acute diarrhoea or gastroenteritis cases are caused by enteric infections. Diarrhoea is the third leading cause of death of under 5 after Malaria and upper respiratory infection. Diarrhoea kills an estimated 2.5 million people each year, with about 60-70% of them being children under five years of age (Cesar et al., 2000). The disease is responsible for over a quarter of the deaths of children in the world today (Yilgwan and Okolo, 2015). Most of these deaths occur in developing countries where an estimated 25% of under-five mortality is directly attributed to diarrhoea disease (Cesar et al., 2000; Yilgwan and Okolo, 2015).

1.3 AIM AND OBJECTIVES OF STUDY:

The aim of this study is to find out bacteriological quality of ready-to-eat (RTE) RICE sold in and around Oduduwa University by ascertaining the bacteria contaminating various RTE rice.

1. To isolate and identify bacterial species associated with food
   contamination.
2. To determine the bacteriological analysis in the ready to eat rice
3. To determine the antimicrobial susceptibility of the microorganisms to the antibiotics.
4. To establish the public health implication of consumption of such
   foods.

CHAPTER TWO

2.0 - LITRETURE REVIEW:

2.1 - FOOD

Food borne illness caused by microbial contamination of foods in an important international public health problem and is known to be a major cause of diarrhoea disease especially in developing countries (Mensah, 2007). In these developing countries a major source of ready - to - eat foods are prepare and or sold at public places such as markets place, schools, canteens and along the streets, all together termed street foods (SFS). The SFS offer food at relatively cheaper cost and at easily accessible places. Furthermore, it offers the traditional meals and preparations of a number of them are quite laborious and time consuming. (Chakra Varky and Canet, 2002). However, a number of observational studies have shown that these foods are sometimes held at improper temperature, excessively handle by food vendors and sold at very dirty surrounding (WHO, 2001, 2003; Ghosh et al., 2007). In addition the vendors practice poor personal hygiene and reports of food vendor being carriers and therefore could serve as a potential source of transmission of enteric fevers are many. Most of the vendors have had either no formal education or few years of schooling and therefore, lack knowledge on proper food handling and their role in the transmission of pathogens (Mensah et al., 2007). At the same time, most of the people who patronize these foods are more interested in its convenience than question of its bacteriological quality and hygiene. The bacteriological quality of food indicates the amount of bacterial contaminants it has; a high level of contamination indicates low quality and more likely to transmit infection. The concerns have been raised by the Food and Agricultural organization (FAO) and other about these foods serving as a potential source of food poisoning outbreaks (Chakravarty and Canet, 2002). In Nigeria, consumption of street food has witnessed a phenomenal growth over the years as rapid population growth over the years as rapid population growth, Urbanization, Unemployment and poverty; occupational pressures and lifestyles changes has created a poll of mobile and transient population who depend almost entirely on these relatively low cost foods for their nutrition. (Martin, 2006).
Although epidemiological data on the incidence of foodborne diseases are inadequate, and the outbreak often not investigated, the recurrent episodes of food borne illnesses with symptoms of gastro intestinal distress like diarrhoea, vomiting, abdominal cramp and nausea has remained a major cause of mortality and morbidity in Nigeria. (Nweze, 2010). Chemicals heavily metals, parasites, fungi, viruses and bacteria can cause food – borne illness, bacteria related food poisoning is the most common. More than 90% of the cases of food poisoning each year are caused by Staphylococcus aureus, Salmonella spp, Clostridium perfringes, Clostridium botulinum, Campylobacter, Vibro parahaemolyticus, Bacillus cerus. These bacteria are commonly found on many raw foods such as rice. Normally a large number of food poisoning bacteria causes illness, therefore illness can be prevented by controlling number of bacteria present, by preventing the small number from growing, destroying the bacteria by proper cooking and avoiding re contamination (De Boer and Beuner,2011). Poor personal hygiene, improper cleaning of storage and preparation areas and unclean utensil causes contamination cooked rice. Mishandling of raw and cooked rice allows bacteria to grow. The temperature range in which most bacteria grow is between 40 degrees (50c) and 1400f (600c). Raw and cooked rice should not be kept in this danger zone any longer than absolutely necessary. Analysing rice for the presence of both pathogenic and spoilage bacteria is a standard way of enduring food safety and quality (De Boer and Beuner, 2011). If microorganisms are able to survive and grow on food which are sold and consumed by people, then the risk of food borne illness is increased in the society. The presence of microorganisms on rice can be important, because the essential nutrients of rice is ingested by some organisms which stimulates growth, while some organisms are known to be pathogenic to man as long as their growth conditions are favourable (De Boer and Beuner, 2011).
Majority of food borne illnesses are caused by harmful bacteria which are tiny organisms responsible for the infectious of the gastrointestinal tracts. Some harmful bacteria may also be present in food when they are purchased, raw foods including meat, poultry, fish, eggs, diary product and fresh produce often contain bacteria that c auses food borne illness, food may be contaminated with bacteria during food preparation.
Bacteria may pass from equipment to the rice when the equipment that has touched other foods has not been properly cleaned and sanitized before being used to prepare the rice (James, 2005). When rice with harmful bacteria is ingested there is a period of time before symptoms of the food – borne illness begin. The amount of times varies with the different bacteria, how many consumed and the individual’s physical condition. Many different harmful organisms produce the same symptoms. (FDA, 2004).

2.2 RICE

Rice is a seed of the grass species Oryza sativa (Asian rice) or Oryza glaberrima (African rice). As a cereal grain, it is the most widely consumed staple food for a large part of the world’s human population, especially in Asia. It is the agricultural commodity with the third-highest worldwide production, after sugarcane and maize, according to 2012 FAOSTAT data. (September 4, 2015). Rice is the most important grain with regard to human nutrition and caloric intake, providing more than one-fifth of the calories consumed worldwide by humans. (Smith, Bruce D, 2007), first used in English in the middle of the 13th century, the word “rice” derives from the old French ris, which comes from Italian riso, in turn from the latin oriza. (Henry George Liddell and Robert Scott, March 13, 2014). Rice itself is a widely consumed commodity, it is widely accepted in the whole wide world, rice is considered a first aid treatment, rather than a cure for soft tissue injuries. The aim is to manage discomfort and internal bleeding. (Jarvinen TA et al.,2007).

HEALTH BENEFITS OF RICE

i. Great Source Of Energy: since rice is abundant in carbohydrates, it acts as fuel for the body and aids in the normal functioning of the brain. Carbohydrates are essential to be metabolized by the body and turned in to functional and usable energy.
ii. Cholesterol Free: eating rice is extremely beneficial for the health simply because it does not contain harmful fats, cholesterol or sodium, it forms an integral part of balanced diet.
iii. Blood Pressure Management: Rice is low in sodium, so it is considered one of the best foods for those suffering from high blood pressure and hypertension. Sodium can cause veins and arteries to constrict, increasing the stress and strain on the cardiovascular system as the blood pressure increases.
iv. Cancer Prevention: Whole grain rice like brown rice is rich in insoluble fibre that can protect against many types of cancer. Many scientists and researchers believe that such insoluble fibres are vital for protecting the body against the development and metastasis of cancerous cells.
v. Rich in Vitamins: It’s an excellent source of vitamins and minerals like niacin, vitamin D, calcium, fibre, iron, thiamine and riboflavin. These vitamins provides the foundation for body metabolism, immune system health and general functioning of the organ systems.

2.3 FOODBORNE DISEASES

The centers for Disease control and prevention (CDC) estimates that approximately 76 million people within the United States contact food-borne illness each year (CDC, 2004). Of those 76 million cases, 325,000 hospitalization and 5,000 deaths results. The CDC preliminary food net data reports that in 2005, there were 15,600 diagnosed cases of food-borne illness caused by bacteria pathogens and of these total 6,017 cases were attributed to salmonella, 5,215 to campylobacter, 3,021 to shigella 443 to Escherichia coli. (CDC, 2004). Most food-borne illness are classified as “acute” they are usually self-limiting and of short duration with symptoms including wild gastro-enteritis. However some illness progress to life threatening neurological or renal syndromes called sequelae. Harmful micro organisms may contaminate rice during receiving, during preparation and serving, during preparation techniques such as cooking and cooling, by coughing or sneezing, from unsanitised facilities and equipment, from disease spreading pest such as cockroaches, flies and mice (CDC, 2004).

2.4 FEATURES OF COMMON RICE –BORNE BACTERIA PATHOGENS

Staphylococcus aureus

Man’s respiratory passage, skins and superficial wounds are common sources of staphylococcus aureus. When Staphylococcus aureus is allowed to grow in rice, it can produce a toxin that causes illness. Although cooking destroys the bacteria, the toxin produce is heat stable and may not be destroyed. Staphylococcal food poisoning occurs most often in rice, sometimes rice is left at room temperature for periods of time, allowing the bacteria to grow and produce toxin. Good personal hygiene when handling foods will keep Staphylococcus aureus out of rice and refrigeration of raw and cooked rice will prevent the growth of these bacteria if any is present (Wagner, 2001)

Salmonella spp.

Is a generic name applied to a group of nearly 2,000 biochemical related serotypes responsible for rice-borne illness. The disease is grossly underreported because it is generally self- limiting gastroenteritis which may be misdiagnosed as intestinal influenza by patient or the physician. As a consequence, estimates of the true incidence of disease are based as assumptions derived from epidemiological evidence. Clearly, salmonellosis continues to be an important cause of food-borne disease worldwide.
Two clinical manifestations caused by Salmonella are recognized: enteric fever (a severe, life threatening illness) and the more common foodborne illness syndrome: In both cased, the oral route. Enteric fever, commonly referred to a typhoid fever, is primarily caused by one species, Salmonella typhi. But other Salmonellae such as Salmonella paratyphi are potentially capable of producing this syndrome. The illness is commonly associated with foreign travel and affects an estimated 800 people annually (Mead et al; 1999). Although the route of entry of the pathogen into the body is primarily oral, the symptoms of enteric fever are generally not elicited through the intestinal tract. However, a short episode of vomiting and diarrhoea sometimes occurs in the first day or two in typhoid fever. The onset times vary considerably between typhoid and paratyphoid enteric fevers. Onset time for typhoid is usually 8 – 15 days, seldom as short as five days but sometimes as long as 30 – 35 days; while onset time for paratyphoid fever tends to be shorter, and may be so short as to suggest typical food poisoning. (Parker, 1984). Salmonella are destroyed at cooking contamination, cooked rice occurs from contact with utensils that were not properly washed after use with raw products. If salmonella is presented in raw or cooked rice, its growth can be controlled by refrigeration below 40ºF. There are various environmental sources that include water, soil, kitchen surfaces and animal faeces that helps in the transmission, Salmonella are transmitted through the faecal matter of people or animals and are usually transmitted to humans by eating foods that have been contaminated with faecal matter via cross-contaminations. As few as 15 to 20 cells depending on the age and health of the host and strain of bacterial are necessary to cause illness (FDA, 2004). It is estimated that approximately 40,000 cases of Salmonelosis are reported each year in the U.S.A. (FDA, 2004).

Shigella spp.

The members of genus Shigella are non-motile, non-spore-forming rods. The Gram reaction is negative and they are capable of growing in aerobic and anaerobic conditions. Biochemically these bacteria ferment sugars with production of acid but no gas, lactose fermentation is very rare and, excluding Shigella dysentriae serotype 1, all members are catalase and nitrate positive, oxidase test is negative in all members except Shigella dysenteriae type 1. O antigen is the basis of serogroups among Shigellae.

Pseudomonas aeruginosa

Belongs to the family Pseudomonadaceae. It is a Gram negative rod, motile with monotrichous flagella. The organism ferments sugar by oxidation. Pseudomonas aeruginosa is oxidase, catalase and citrate positive. It is also capable of growing on higher temperatures ranges from 41-42ºC. Blue-green fluorescent color (pyocyanin) is the mark of identification for P. aeruginosa.

Escherichia coli

Escherichia coli was first described by Theodor Escherich in 1885 as Bacterium coli commune, which he isolated from the faeces of newborns (Todar, 2008). In 1935 a strain of E. coli is shown to be the causative agent in an outbreak of diarrhea in infants, although for many years it was considered a simple commensal bacterium of the large intestines (Todar, 2008). E. coli is now used as an indicator of faecal pollution that originates from human and warm-blooded animals (Omar and Barnard, 2010). E. coli survives in drinking water for between 4 and 12 weeks, depending on environmental conditions (temperature, micrcroflora, etc.) (Okeke et al., 2000).
E. coli is found in mammal faeces at concentration of 109 cfu/100 ml, but it does not multiply appreciably in the environment (Edberg et al., 2000). Although usually harmless, various E. coli strains have acquired genetic determinants (virulence genes) rendering them pathogenic for both humans and animals. These pathogens are responsible for three main types of clinical infections: (i) enteric and diarrheal diseases, (ii) urinary tract infections and (iii) sepsis and meningitis (Bekas et al., 2003). Virulence factors involved in pathogenic mechanisms of E. coli include adhesins, host cell surface-modifying factors, invasins, toxins and secretion systems (Bekal et al., 2003). E. coli is the most common bacterial pathogen associated with endemic forms of childhood diarrhea in developing countries (Okeke et al., 2000) including South Africa, especially in regions with poor sanitation.
Based on the presence of different chromosomal or plasmid-encoded virulence genes, their pattern of interaction with epithelial cell and tissue culture monolayers enteropathogens are classified into six categories: E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. coli (EHEC), enteroaggregative E. coli (EAEC), and diffusely adherent E. coli (DAEC) (Okeke et al., 2000; Nataro and Kaper, 1998).

Enterotoxigenic E. coli (ETEC)

Enterotoxigenic E. coli is the most common pathotype, particularly in developing countries and is recognized as an emerging enteric pathogen (Osode and Okoh, 2008; WHO, 2000). ETEC strains produce heat-liable toxin (LT), heat-stable toxin or both toxins and colonization factors allowing the organism to colonize the small intestine with subsequent development of diarrhoea (Osode and Okoh, 2008). A number of different O serogroups and H serotypes are represented among ETEC strains (Mahdy et al., 2010). ETEC is the common cause of traveller’s diarrhoea and it is also responsible for diarrhoea in children in the developing world (Nataro and Kaper, 1998) and adults (4.5%) presenting to emergency departments and inpatient units in the United States (Osode and Okoh, 2008; Cohen et al.,2005; Nataro et al., 2006).
The incubation period for ETEC is between 14 to 50 hrs (Nataro and Kaper, 1998) causing watery diarrhoea similar to that of Vibrio cholera, usually without blood or mucus (Benenson, 1995), fever may not be present and the disease is self-limiting (Benenson, 1995; Beutin et al., 1998). The most common vehicles for ETEC infection are food and water contaminated with faeces (Zuber, 1999). There are about 400 million episodes of diarrhoea with ETEC that occur annually worldwide, with an estimated 700,000 deaths (Mandy et al., 2010; Putnam et al., 2004).

Enterohemorrhagic E. coli (EHEC)

Enterohemorrhagic E. coli also known as E. coli 0157:H7 surfaced in the last decade as an important food-borne pathogen with 73,000 cases of annual infection in the United States (Rangel et al., 2005; Zhao et al., 2006). Several studies have shown cattle to be the major reservoir of E. coli 0157:H7, thus the cattle drinking water troughs are an important source of this pathogen on farms (Bach et al.,2004; Bach et al., 2005; Al-Saigh et al., 2004; Bosilevac et al., 2004; Low et al., 2005; Sheng et al., 2004).
Most studies indicate that E. coli 0157:H7 can survive in cattle drinking water up to 12 months and that the pathogen can be easily disseminated to other cattle (Faith et al., 1996; LeJeune et al., 2005; Shere et al., 2002) and subsequently to the environmental source waters used for human consumption.

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