MICROBIOLOGICAL EXAMINATION OF SURFACES OF CANNED DRINKS

ABSTRACT

Contamination of canned drinks surfaces with foodborne pathogens remains an important public health issue, because it lead to illness if there are malpractices in handling and storage of the product. The microbiological examination of canned drinks were analyzed to determine their level of surface contamination. 27 samples of canned drinks were collected from three different locations (distributor in Umuahia, supermarket in Ahiaeke and kiosk in Bende road) all in Umuahia metropolis. For every store or shop, nine sets of samples were collected, three (3) from the shelf, three (3) from the fridge and three(3) used as control. The isolation, identifications, characterization and microbial counts were done using standard microbiological techniques methods.  All the canned drinks samples examined were contaminated with some bacterial and fungal species namely, Klebsiella species, Bacillus species, Escherichia coli, and Staphylococcus aurues, and fungal isolates were Mucor species and Aspergillus species. The shelf samples have microbial loads from 2.3 x 101 to 6.3 x 101; while the rinsed with water samples (control) range from 1.4 x 101 to 3.2 x 101.The refrigerator samples have microbial loads from 1.1 x 101 to 2.9 x 101 while rinsed with water samples(control) range from 1.1 x 101 to 2.1 x 101. Escherichia coli had the highest percentage occurrence 13(17.7%), followed by staphylococcus species 11(13.0%) and the least was Pseudomonas species 3(5.1%). These finding suggest that most of the canned drinks stored in the open market may constitute sources of microbial food poisoning and public health hazard.

TABLE OF CONTENTS

Title Page                                                                                                                                i

Certification                                                                                                                           ii

Dedication                                                                                                                              iii

Acknowledgement                                                                                                                  iv

Table of Contents                                                                                                                   v

List of Tables                                                                                                                          vii

Abstract                                                                                                                                  viii

CHAPTER ONE

1.0           INTRODUCTION

1.1       Aims of the Study                                                                                                       4

1.2       Objectives of the Study                                                                                              4

CHAPTER TWO

2.0           LITERATURE REVIEW

2.1       Composition of Canned Drinks and Canned Drinks in Relation to Spoilage          6

2.2       Surface Contamination                                                                                              7

2.3       Microbiological Contamination of Surfaces                                                                 8

2.4       Food Borne Illnesses                                                                                                  9

2.5       Growth Factors of Microorganisms                                                                                  13

2.6        Microbiological Spoilage of Canned Drinks                                                            16

CHAPTER THREE

3.0       MATERIALS AND METHODS

3.1       Collection of Samples                                                                                                21

3.2       Preparation and Sterilization of Culture Media                                                        21

3.3       Enumeration of Bacterial Isolates                                                                                    21

3.3.1    Bacterial Count                                                                                                           21

3.3.2    Identification and Characterization of bacterial isolates                                     22

3.3.3    Gram staining technique                                                                                             22

3.3.4    Biochemical tests for bacteria                                                                                     22

3.4       Enumeration of Fungal Isolates                                                                                    24

3.4.1    Fungal Count                                                                                                              24

3.4.2    Identification and Characterization of Fungal Isolates                                        24

3.4.3    Examination of Fungal Hyphae                                                                                   24

CHAPTER FOUR

4.0       RESULT

4. 1      Microbial Count                                                                                                          25

4.2       Discussion of Results                                                                                                 37

CHAPTER FIVE

5.0       CONCLUSION AND RECOMMENDATION

5.1       Conclusion                                                                                                                  39

5.2       Recommendation                                                                                                        39

References                                              40

LIST OF TABLES 

Table                                 Title                                  Page

Identification and characterization of Fungal Isolates from surface of canned drinks.

CHAPTER ONE

INTRODUCTION

In 1810, Englishman Peter Durand patented the preservation of food in tin-coated iron cans then in 1813 two other Englishmen Brian Donkin and his brother-in-law John Hall bought Durand’s patent to set up the first commercial canning operation in London (Michaels, 2003). One year before the London commercial operation, Thomas Kennett started canning meats, fruits and vegetables in New York City. Although food had been sold in cans for many years, the first commercial can of beer was sold in Richmond, VA in January of 1935 and by the end of that year over 200 million cans of beer had been sold (Lee, 2003). First introduced in 1965, aluminium beverage cans now make up about 75% of the beverage can market share and according to the aluminium can manufacturers association there are about 100 billion aluminium beverage cans produced in the US each year (Gangar,2003). There are many different container types and materials used to package beverages, such as glass bottles, aluminium cans, and plastic bottles, all of which have the potential to become contaminated. With the popularity of beer and soft drinks, beverages stored in cans are extremely common. These cans are often transported and stored in packaged boxes. Cans are often packed and displayed with the tops uncovered. During storage and transportation, microorganisms may contaminate cans. Thus when drinking from a can, one’s mouth comes in direct contact with the can lid allowing possible transfer of microorganisms (Gangar, 2003).

Canned drinks, according to Kigighai and Jonathan, (2012) are defined as packaged beverages which might be non-alcoholic, non-carbonated or carbonated and flavored. They are best enjoyed when served cold. Different variations or variants of canned drinks exist depending on the flavored ingredients which include: lemon, orange, lime, assorted fruit-juices, colas, ginger ales, sodas and root beers according to CSDA, (1996). It is often a cliché in microbiology that “microorganisms are ubiquitous” in that they are able to survive and live everywhere they deem fit. Thus there might not be any place on the earth surface that is devoid of microbial forms. Bacteria in particular like other microbial forms are known for their ability to survive in different environments such as on soil, air, water and canned drinks. More so, they have been found to grow on certain materials which are deplete in nutrients and moisture such as clothing, glassware and other inanimate objects  (Pelczar et al., 1993). 

Canned drinks represent an important market within the food industry. The increasing variety of products being released at a bewildering rate has altered the potential for spoilage problems. Canned drinks are generally nutrient poor media that are spoiled by relatively few organisms – usually yeasts, and a few acid-tolerant bacteria and fungi. Carbonation shifts the spoilage flora to those organisms tolerant of carbon dioxide. Canned drinks enhanced by the addition of low levels of fruit juice tend to exhibit similar spoilage flora to canned drinks. The use of ever more exotic raw ingredients may lead to the discovery of unusual spoilage organisms in the future. Yeasts in general, and Zygosaccharomyces bailii in particular, remain the key spoilage organisms because of their overall physiology and resistance to organic acid preservatives (Stratford et al., 2000).

Several studies have shown that microbes have been able to colonize inanimate objects such as beverage packages and other items used to consume beverages (Dantas et al., 2006); mobile phones of health care staff/workers (Kilic et al., 2009) and household surfaces as well as food surfaces (Othman, 2015). Microorganisms are not just ubiquitous in nature but a plethora of their activities in the environment can lead to positive or negative consequences on humans, animals and plants. 

There are few published work on the associated health risk to consumers of canned or bottle canned drinks due to microbial contamination from the surfaces and orifces especially in the third World and developing countries. Kigighai and Jonathan (2012), carried out the microbiological survey of non-alcoholic carbonated beverages and reported the presence of bacterial pathogens such as Staphylococcus, Bacillus, Enterococcus, Micrococcus Proteus and Pseudomonas species which are of public health significance. Griffiths et al. (1997) carried out an analysis of the quality of the ingredients used in the Canned drink Industries. In the City of Ibadan, Amusa et al. (2005) carried out microbiological and nutritional studies on the quality of hawked sorrel drinks popularly known as zobo and the report revealed a plethora of microbial contaminants of public health importance which include Bacillus cereus, B. subtilis, Staphylococcus, Streptococcus and Escherichia. Fungal contaminants were also reported which are basically species in the genus Aspergillus, Penicillium, Fusarium and Rhizopus. Oranusi et al. (1994) in a technical report, studied the microbial contaminants of commercially bottled non-alcoholic beverage available in Nigeria at the time and 50% of a total of analyzed 90 samples were contaminated mainly with saprophytic and non-pathogenic bacterial species such as Bacillus, Lactobacillus, Pediococcus, Staphylococcus epidermidis and Micrococcus. 

With the recent news of leptospirosis on the internet (Gompf, 2017; CDC, 2017), there are concerns over the safety of consumers who consumes canned drinks most especially canned drinks directly from the orifice. Just as the definition of canned drinks goes, it is best consumed when cold or chilled thus most consumers do not take cleaning the canned drink surfaces seriously before consumption while others are under the assumption and illusion of the fact that when it is brought out of the refrigerator cold or chilled, it is apparently safe for consumption. Contamination of canned drinks surface can occur anywhere including environment where it was manufactured to the point of storage in the refrigerator as well as point of consumption. Studies have shown that certain bacterial and fungal species of public health importance are able to survive refrigeration temperature (Davenport,1995a).

Kregiel, (2015) reported that Canned drinks consumption is still a controversial issue for public health and public policy. Through the years, several studies have been carried out to evaluate the possible links between the consumption of canned drink and associated health problems. The findings, however, remain highly contested. Nonetheless, there is an increasing emphasis being placed on the health properties of canned drinks, by both the industry and the consumers. Moreover, there are extant rules already in place to ensure that manufacturers of canned drinks conform to established national and international standards (Davesmith, 1997). Most consumers believe that the canned drinks are safe for consumption in whatever form and that their quality is guaranteed; but little do they understand that there is also another reason to worry over our public health as it concerns canned drinks or food. Hygiene is one aspect of science that most persons do not give much credence to. Notwithstanding, in the science of hygiene, everything is a potential infection vehicle including the orifice or surfaces of canned drinks (Czajka,2005a).

1.1       AIMS OF THE STUDY

The aim of the study is to examine the microorganisms from surfaces of canned drinks sold at different locations in Umuahia metropolis, Abia state.

1.2       OBJECTIVES OF THE STUDY

The objectives of the study includes:

1.     To isolate and characterize microorganisms (bacteria and fungi) present on the surfaces of canned drinks sold in Umuahia metropolis

2.     To determine the microbial loads of contaminated canned drinks surfaces.

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