ASSESSMENT OF MICRO ORGANISMS IN MINIMALLY PROCESSED FRUITS AND VEGETABLES

ASSESSMENT OF MICRO ORGANISMS IN MINIMALLY PROCESSED FRUITS AND VEGETABLES

ABSTRACT

Vegetables and fruits that have been physically altered from its original state but remain in its fresh state are considered minimally processed. Fresh fruits and vegetables are an important source of nourishment and a vital ingredient in healthy and balanced diets. Minimally processed fruits and vegetables are good media for growth of microorganisms, infact the habour potential pathogens. They have been involved in disease outbreaks because of the consumption of products contaminated by pathogens. They are also sensitive to various spoilage microorganisms such as salmonella Spp. Shigella Spp. E. Coli and a host of other pathogenic organisms. Contamination of minimally processed fruits and vegetables occurs at every stage of the food chain, from cultivation to processing. Polluted environments or a poor hygienic condition in minimal processing (that is during peeling, cutting or slicing) increases the risk of contamination with foodborne pathogens. The four fruits and three vegetables (water melon, pineapple, paw-paw citrus, Pumpkin, Spinach and Cabbage) assessed bacteriologically had high viable counts even though within tolerable limits. A good pre-decontamination of these fruits and vegetables can be achieved through various forms of washing as shown by this study will reduce the density of the microbial load. These forms of washing include: washing with tap water, washing with distilled water or washing with salted water. This work has been able to determine the total bacterial load of the minimally processed fruits and vegetables from Nasarawa local market. And it has also been able to access the effectiveness of some selected antibiotics in other to treat some of the disease that can arise as a result of the consumption of the contaminated food.

CHAPTER ONE

1.1     INTRODUCTION

Vegetables and fruits that have been physically altered from its original state but remain in its fresh state are considered minimally processed. Fresh fruits and vegetables are an important source of nourishment and a vital ingredient in healthy and balanced diets. Fresh produce is highly recommended in any diet, virtually without quantitative restriction. Minimally processed fruits and vegetables are products that undergo some industrial or manual processing (such as peeling, slicing, chopping, shredding, trimming, washing or packaging) which make them ready for consumption. However, in this dicing step occurs the release of internal cellular fluid rich in nutrients, which allow microorganisms to multiply rapidly increasing the initial microbial load and thus reducing considerably the shelf life of these products. Washing and soaking with sanitizing chemicals, followed by slicing, are stages of a complex, multipart process developed to preserve and guarantee the quality of minimally processed fruits and vegetables. Packaging in modified atmospheres, together with refrigeration, slows down air flow and consequently the respiration of the vegetables. Bacterial growth is also inhibited, and the shelf-life of the product is enhanced. (Fallik and Aharoni, 2004).

Advances in processing and conservation technologies, together with better distribution and trading, have made nearly all kinds of fresh fruits and vegetables available, with good quality. On the other hand, some of the technologies employed have increased health hazards, mainly associated with pathogenic microorganisms. Several outbreaks of gastroenteritis (A condition that causes irritation and inflammation of the stomach and intestine) have been imputed to the consumption of contaminated fresh vegetables. Toxin infections associated with ingestion of vegetables, which revealed a lack of hygiene during manipulation, have been recorded. 

Food-borne parasites have received little attention in developing countries. As a rule, these organisms infest fruits vegetables while still in the field, and are usually transmitted by contaminated wash water and spread by ineffective hygiene practices. Control of protozoan and helminthes is a constant object of public-health strategies, especially where reclaimed water is used. The resistant cysts or eggs of these organisms enhance their survival in the natural environment. (Anjezaeoku, 2011).

Food safety in ready-to-eat products, especially raw foods, has long been an object of study. In order to effectively assess all the steps in a minimal-processing plant and to analyze the entire food-production chain, it is important to identify the origin of the likely contaminants. A number of studies have assessed the microbiologic conditions of ready-to-eat fruits and vegetables available in supermarkets, street markets, and grocery shops, as well as in self-service and fast-food restaurants. (Anjezaeoku, 2011)

From the quality stand point it is desirable to preserve the quality and characteristics of minimally processed fruits and vegetables at their peak. What the consumer perceives as the most appealing attribute of this products include: their fresh-like appearance, taste and flavor, in addition to convenience. Obviously any food product should be safe for consumption and minimally processed fruits and vegetables are very prone to contamination. Some of the effects of contamination of minimally processed food include: discoloration or browning, desiccation, microbial spoilage’ Texture changes and development of off-flavor or off-odor. (S.Demelo Silva, 2001).

There are few factors that increase the risk associated with minimally processed fruits and vegetables above that of their non-processed counterparts. First, the more a product is handled and the longer between production and consumption, the more opportunity there is for contamination of the product. Secondly, most minimally processed or ready-to-eat products are meant to be taken home and eaten with no further washing or processing needed. The lack of any step that will kill or reduce the level of contamination before consumption increases the risk of consumer’s exposure to pathogens. Thirdly, in processing the peel or rind is often disrupted by cutting or peeling. The peel or rind can act as an effective barrier to microbial or chemical contaminants, so when it is disrupted, it leaves the fruits more vulnerable to contamination. Also when the rind happen to be contaminated, when it is cut the contaminant can be transferred to the flesh which is more likely to be consumed. (Silva et al., 2010)

Biological, chemical and physical hazards May contacts fruits and vegetables through vectors such as water, air, equipment, pest and people. These vectors allow hazard to contact fruit, resulting in contamination during processing. Water is a common vector used for rinsing, washing and sanitizing of fruits and equipment during processing. It can be a major source of exposure to hazards if not properly managed. The quality of the water used is extremely important because of the large amount of contact it has with both fruits and equipment. (Zagory, 1999).

Minimal processing in which fruits and vegetables are subjected to renders the products highly perishable, hence requiring chilled storage to ensure a reasonable shelf-life, this is as a result of the exposition of the internal tissues to microbes and potentially deleterious endogenous enzymes. Among the possible consequences of mechanical injury to produce are increase in respiration rate and ethylene production, accelerated senescence and enzymatic browning (Pixley, 1913).

1.2     AIM AND OBJECTIVES

The aim of this project work is to assess the microorganisms in minimally processed fruits and vegetables and to provide a systematic review of the potential food safety risks from pre-processing to sale in the market. The general objectives are:

·        Identify the various pathogens that are found on minimally processed fruits and vegetables.

·        The effects of these pathogens on human health

·        Develop more effective technology for decontaminating minimally processed fruits and vegetables containing human pathogens

·        Proffer ways of improving the packaging of these fruits and vegetables so as reduce micro organism infestation

1.3     SCOPE AND LIMITATION

The scope of this project is to assess micro organisms in minimally processed fruits (citrus, pineapple, water melon, paw-paw and mango) and vegetables (cabbage, spinach, okro) which are mostly consumed within our locality.

The micro organisms of interest in this study are the pathogenic organisms, that is; micro organisms that are capable of causing diseases and are detrimental to health with special emphasis on Samolnella spp  Shigella dysenteriae and Escherichia coli. And also assess the effects of this pathogen on human health and probable solution to such hazard based on the results obtained from the assessment.

1.4     STATEMENT OF PROBLEM

Minimally processed fruits and vegetables are products that are in high demand due to the fact that it is a ready to eat product, hence assessing the microbial load as well as providing possible solution in order to prevent contamination is of paramout importance.

The major constraint of this project is the cost implication, that is, the cost of purchasing all the media (agar), as well as the materials required.

Another important problem is difficulty involved in maintaining an aseptic condition throughout the analysis in order to obtain accurate result.  

1.5     JUSTIFICATION

The complete execution of this project work (assessment of microorganisms in minimally processed fruits and vegetables) will be of relevance in the following ways:

·        Production of micro-organism free fruits and vegetables for the teaming population

·        Proper packaging of minimally processed fruits in such a way that microorganism infestation would be minimal.