Abstract

Garlic and Ginger are hardy perennial of Asiatic origin, belonging to the plant family liliaceae. Investigations were carried out to study the inhibitory effect of ginger (Zingiber officinale) and garlic (Allium sativum) extracts at 0.5, 1.0, 2.0, 7.0 and 10.0 per cent level in vitro on Escherichia coli and Listeria monocytogenes by spectrophotometer method. Both the spices exhibited bacteriostatic effect against both the test organisms. The inhibitory effect increased with the increase in the concentration of extracts. The garlic extract was more effective against E. coli than L. monocytogenes. Ginger extract was effective in restricting the growth of E. coli at 0.5, 1.0 and 2.0 per cent level. The minimum inhibitory effect of ginger extract was found to be 8.7 and 8.5 for E. coli and L. monocytogenes respectively, whereas in case of garlic extract it was 9.1 and 8.0, respectively. It was concluded that both the spices possess a good potential to act as natural preservative.

CHAPTER ONE

1.0 INTRODUCTION

Ginger (ginger rhizome ) is the root of the Zingiber officinale plant, which can be utilized as a medication or as pleasant condiments. They are grown in Northern Nigeria as medicine for both human and animals. They are primarily used for seasoning and also for its medicinal property.

1.1 BACKGROUND OF STUDY

Ginger derived its name from the genus (Zingiber officinale) and the family (Zingiberaceae). In addition to ginger, there are other important followers to this plant family including turmeric, cardamom and galangal. Zingiber officinale creates sets of flower sprouts (pink and white) that developed into yellow flowers. As a result of the beautiful appearance and the habituation of plant to hot weather, Zingiber officinale is usually utilized as scenery across subequatorial homes.  

Fully developed Zingiber officinale roots are fibrous and approximately arid. The syrup from ancient ginger rhizomes is highly strong and usually utilized like condiments in Indian prescription, and is as typical component of cooking in many Asian countries also this return to its pleasant relish which makes the taste of many food dishes an extremely delicious.   Zingiber officinale plays role as powerful food maintenance. In limited studies, ginger was found to have better effectiveness than placebo in relieving disgust produced by sea dizziness, morning dizziness, despite ginger is not reported to be preferred on placebo in relieving surgical sickness. The plant is reported to have antibacterial, anti-oxidant, antiprotozoal, anti-fungal, anti-emetic, anti-rhinoviral, anti-inflammatory, anti-insecticidal activity. Reported pharmacological activities of ginger include antipyretic, analgesic, ant tissues in addition to hypersensitive effects.

Ginger extract also showed a hepatoprotective effect in rats. Besides that, Ginger was found to have free radical remover activity (prevent oxidant formation); so prevents lipid oxidation. This finding can explain the well documented gastro-protective effects. Additionally, ginger extract has radiopreventive activity which could be useful in preventing gamma radiation from generating adverse reactions during the course of cancer therapy in laboratory animal. Moreover, ginger displayed chemopreventive and antineoplastic effects; also ginger shows to have in the future role in cancer inhibition, although additional studies are required to assess this property of ginger . Patients with diabetes mellitus (cataract) might have  developed glycation end-yield  for this case ginger is chosen because of its antiglycating property.

Allium sativum was utilized to inhibit gangrene formation through the first and Second World War. In new researches, it is reported that garlic extract has been proved to be efficient toward Streptococcus mutans, garlic extract mouth wash may be utilized as a modern line in inhibiting dental caries formation. Garlic is highly documented in exhibiting powerful antimicrobial activities. Garlic can provide proper management for bacterial growth ranging from disinfectant, antiseptic, bacteriostatic and even bactericidal characteristics.  Besides that, garlic may have the ability to prevent and manage viral, fungal and even helminthes infections. Newly obtained garlic has been found to impart a significant role in managing food poisoning through killing the causative agents such as Escherichia coli. Recently, it has approved that there is a possibility of using garlic in preserving meats from bacterial spoilage and this related to the antibacterial activity of garlic.  

Listeria monocytogenes and Escherichia coli have been isolated from various types of foods and associated with food borne infection in man. The presence of these organisms and their growth and multiplication in food do not produce much appreciable changes in foods but leads to food borne infection. In order to prevent the growth of bacterial pathogens in food, various preservative techniques have been used. Consumer concerns on the safety of foods containing synthetic chemicals as preservatives have resulted in a growing need for use of natural antibacterial compounds, having a characteristic flavour, antioxidant and antimicrobial activity. Currently, various natural compounds like spices are preferred and used as food preservatives. Kerala, a south Indian state in tropical Asia is a well-endowed state with numerous varieties of spices. Spices form an integral part of the traditional cuisines in the everyday diet of the common man here. With globalisation and increased recreational travel, intercontinental modification in the local cuisines has resulted in vast changes in traditional cooking methods. The anti-microbial properties of various natural spices against emerging pathogens have to be taken advantage of, with the changing lifestyle.

Bactericidal or bacteriostatic activity of essential oils in spices against various pathogens including Escherichia coli O157:H7 and Listeria monocytogenes have been reported. The present study was undertaken to assess the direct effect of two of the most commonly used spices, ginger and garlic extracts on Listeria monocytogenes and Escherichia coli. The minimum inhibitory concentrations were evaluated to enable the use of these for microbial control and as food preservative specifically against these two organisms.

1.2 OBJECTIVE OF STUDY

The objective of this study is to explain the antimicrobial activities of garlic and ginger extracts.