Food Microbiology

CHAPTER I INTRODUCTION 1. 1 Background Food is one of human sources of calorie, protein, fats, and nutrition. Yet, because of the highly nutritious content, food is susceptible to growth of microorganisms. By the presence of microorganisms in food, the food is more likely to have shorter shelf life. Thus, mostly it is resolved by the addition of antimicrobial substances to food, such as condiments and preservatives. Condiments and preservatives could inhibit the growth of microorganisms or even destroyed them, as they have antimicrobial agents.Some examples of condiments and preservatives are ginger, clove, sodium benzoate, garlic, and coriander. The factors contributing in the effectiveness of condiments and preservatives in inhibiting the growth of microorganisms are the concentration of the antimicrobial, temperature, characteristic of the microorganisms and food, storage time. As different types of microorganisms have different resistance toward the antimicrobial substance, it is important to understand the characteristic of the microorganisms towards the antimicrobial agent.There are two types of resistance: intrinsic resistance and acquired resistance. There are some methods of observing the capability of the condiments in inhibiting the growth of microorganisms. In the experiment, the method used is well diffusion method, which used different type of condiments and added into holes of agar, where by the inhibition zone by the condiments could be observed. The larger the inhibition zone, the more effective the condiment was in inhibiting the growth of microorganisms. 1. 2 Objectives By conducting the experiment, students are expected to learn and observe he effectiveness of antimicrobial substance consisted in condiments and potassium sorbate towards the growth of microorganisms. CHAPTER II LITERATURE REVIEW 2. 1 Antimicrobials Referring to Volk and Wheeler (1993), antimicrobials are the substances that are used to inhibit or kill pathogenic or non-pathog enic microbes. Antimicrobials are also often used as sanitizers and preservatives. Sanitizer is an agent to decrease the amount of microorganisms to the acceptable level. It is generally used in food processing equipments. Antimicrobials are grouped into natural antimicrobials and chemical antimicrobials.According to Fardiaz (1992), antimicrobials may be microstatic, which is inhibitory to the growth of microbes, and microcidal, which means able to kill microbes. Fruit extract is one most susceptible food materials and thus, is often added with preservatives, especially chemical preservatives, stored at low temperature, or pasteurized. Pasteurization is a heating process at 63? C for thirty minutes. This process is aimed to preserve the stability of the food materials (Buckle et al. , 1987). The growth of microbes can be controlled by using various methods, namely physical method, chemical method, and immunological method.The control of microorganism growth is performed to kill the microbes, to inhibit the microbes, and to destroy the microbes. Physical controls can be performed by sterilization with heating or radiation and filtering. Chemical controls can be carried out by using chemical antimicrobial compounds, such as disinfectants and preservatives. Whereas immunological controls can be performed by vaccination (Batzing, 2002). 2. 2 Active Antimicrobial Compounds in Spices 2. 2. 1 Garlic Garlic come from the onion family and are an erect biennial herb, which grow annually. It has irregular roots, condensed, flattened step and narrow and has lat leaves. Garlic’s bulb consists of 6 to 35 bulblets called cloves which enclosed in a thick whitish, glistening, and transparent covering (Anonym1, 2000). According to Ankri and Mirelman (1999), garlic or Allium sativum or lahsoon in Indian name is an edible plant, which has been generating a lot of interest as a medicinal panacea and a cure for a wide variety of different conditions since the human history h as begun. It is reported to have anticancer effects and to reduce blood lipids in human body. Figure 2. 1 shows the approximate composition of fresh garlic. Figure 2. The approximate composition of fresh garlic Source: Ahmad (1996) The active compound found in garlic cloves which have an unusual concentration of sulfur-containing compounds (1-3%) is called allicin. It is a volatile molecule, which is poorly miscible in aqueous solution, and has a strong typical odor of crushed garlic. Chemically, allicin can be synthesized by mild oxidation of diallyl disulfide as presented in Figure 2. 1. It is to be noticed in Figure 2. 2 that there is a compound called alliin which is a stable precusor, that later will be converted to allicin by enzyme called alliinase present in cloves too.Moreover, alliinase is surprisingly found in large amounts in cloves, which is about 10% of the total protein content. Practically, allicin is produced when garlic cloves are cut into or crushed (Ankri and Mir elman, 1999) Figure 2. 2 Generation of allicin in a garlic clove Source: Ankri and Mirelman (1999) According to Ankri and Mirelman (1999), there are several biological activities in allicin such as its activity as an antioxidant and its ability to attack the sulphur (SH) groups in enzymes and proteins while modifying their activities as well.Furthermore, allicin can rapidly penetrate into cells through the cell membranes. In its pure form, allicin has been reputed to exhibit antibacterial activity against a wide range of Gram-negative and Gram-positive bacteria, for instance Escherichia coli that is known to be a multidrug-resistant enterotoxicogenic strains, Salmonella, Staphylococcus, Streptococcus, Klebsiella, Proteus, Bacillus, and Clostridium. It also has antifungal activity that prevents the formation of mycotoxins such as the aflatoxin of Aspergillus parasiticus.Allicin has shown the anticandida activity towards and is effective against the group species of Candida, Cryptococ cus, Trichophyton, Epidermophyton, and Microsporum at only low concentration since it inhibits both the germination of spores and the formation of hyphae. Referring to Dobre et al. (2011), allicin can also attack Aspergillus, Fusarium, and Penecillium species, which are responsible for food poisoning and food decay.The main mechanism of the antimicrobial activity in allicin is the inhibition of certain thiol-containing enzymes in the microorganisms by the super fast reaction of thiosulfinates with thiol groups, such as alcohol dehydrogenase, thioredoxin reductase, and RNA polymerase that later will affect the essential metabolism of cysteine proteinase activity. The reason why microbial cells are highly sensitive to allicin is probably because the lack of glutathione (thiol molecules such as trypanothione) which results of lack of the ability to reactivate the pivotal SH-enzymes that are thiolated by allicin (Ankri and Mirelman, 1999). . 2. 2 Coriander Coriander or Coriandrum sativu m L. is originated from the Mediterranean region and has the appearance of flat shape in the one side while slightly pointed shape is found in the other side. Coriander seed has various lengths between 3 to 5 mm with brown color in ripe state (Sarkar, 2012). Accodring to Rattanachaikunsopon and Phumkhachorn (2010), it has been traditionally used as an analgesic, aphrodisiac, antirheumatic, anti-inflammatory, diuretic, antispasmodic, circulatory stimulant, and antidiabetic. Beside that, coriander is known to have effect in lowering cholesterol. Table 2. shows the composition of coriander seed. Table 2. 3 The coriander seed composition in 1 tsp Total Fat 0. 9g 1% Saturated Fat 0. 00g 0% Monounsaturated Fat 0. 7g Polyunsaturated Fat 0. 1g Cholesterol 0mg 0% Sodium 2mg 0% Total Carbohydrates 2. 7g 1% Dietary Fiber 2. 1 g 8% Protein 0. 6g Vitamin A 0% Vitamin C 2% Calcium 4% Iron 5% Source: Sarkar (2012) The precise volatile compounds acting as antimicrobial compounds have not been exami ned clearly till now, although there are some volatile compounds suggested to be the antimicrobial compound inside coriander which are (2E) – hexenal and (3E) – hexenal (Kubo et al. , 2004).They are reported to have antimicrobial activity against Gram-negative and Gram-positive bacteria such as Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus, which are foodborne pathogenic bacteria. It also exhibits bactericidal activity and is reported to have an effective antibacterial. The mechanism of the activity of coriander is membrane damage causing cell death to the bacteria (Silva et al. , 2011). However, according to Uma et al. (2009), coriander seems to not having an effective antifungal activity and its activity toward yeast have not yet been examined further. 2. 2. 3 Black PepperBlack pepper (Pipper nigrum) is a condiment that has been used since ancient times and is native to India. Black pepper is useful for treatment of various sicknesses su ch as vertigo, asthma, fever and also cholera. The volatile oil of black pepper has been shown to have antimicrobial activity as well (Karsha and Lakshmi, 2009). The major antimicrobial compund found in black pepper are monoterpenes and sesquiterpenes (Davidson et al. , 2005). According to Karsha and Lakshmi (2009), black pepper shows strong antimicrobial activity against gram-positive bacteria such as Staphylococcus aureus, Bacillus cereus and Streptococcus faecalis.Gram-negative bacteria such as Pseudomonas aeruginosa, Salmonella typhi and Escherichia coli are affected as well, although the effect on gram-positive bacteria is better. The mechanism of the antimicrobial activity appears to be loss of control over cell membrane permeability. According to Singh et al. (2004), black pepper has antifungal activity as well as it is effective in stopping the growth of molds such as Fusarium graminearum. Black pepper is also shown to be able to inhibit the growth of yeast such as Candida a lbicans (Joe et al. , 2009). 2. 2. 4 Potassium SorbatePotassium sorbate are currently one of the most widely used preservative and can be used to preserve foods, animal feeds, pharmaceuticals, and cosmetics. Potassium sorbate may be manufactured as a powder or granules and has an antimicrobial potency of 74% compared to sorbic acid. The molecular weight of potassium sorbate is 150. 22 and is the most soluble form of sorbate compared to the others, such as calcium sorbate and sodium sorbate. Besides good solubility, potassium sorbate is also has good stability and easy to manufacture, making it the most used form of sorbate in food industry.Sorbate is very effective when used against bacteria, molds, and yeasts. Yeasts inhibited by sorbate are Brettanomyces, Candida, Cryptococccus, Debaryomyces, Endomycopsis, Hansenula, Kloeckera, Pichia, Rhodotorula, Saccharomyces, Sporobolomyces, Torulaspora, Torulopsis, and Zygosaccharomyces. Molds species inhibited by sorbate are Alternaria, Asco chyta, Ascosphaera, Aspergillus, Botrytis, Cephalosporium, Chaetomium, Cladosporium, Colletotrichum, Cunninghamella, Curvularia, Fusarium, Geotrichum, Gliocladium, Helminthosporium,Heterosporium, Humicola, Monilia, Mucor, Penicillium, Phoma, Pepularia, Pestalotiopsis, Pullularia, Rhizoctonia, Rhizopus, Rosellinia, Sporotrichum, Trichoderma, Truncatella, Ulocladium, and others. While for bacteria, the species inhibited are Acetobacter, Achromobacter, Acinetobacter, Enterobacter, Aeromonas, Alcaligenes, Alteromonas, Arthrobacter, Bacillus, Campylobacter, Clostridium, Escherichia, Klebsiella, Lactobacillus, Micrococcus, Moraxella, Mycobacterium, Pediococcus, Proteus, Pseudomonas, Salmonella, Serratia, Staphylococcus, Vibrio, Yersinia, and others (Davidson et al. , 2005). 2. 3Mechanism of Antimicrobials There exist some mechanisms of antimicrobial activity in inhibiting the growth of microbes. The antimicrobials are classified into: cell wall destructor, cell wall permeability intervent ion, destructor of proteins, nucleic acids, and enzymes, antimetabolites, inhibitors of nucleic acid synthesis, and cell plasmolysis (Fardiaz and Betty, 1989). Referring to Fardiaz and Betty (1989), the broken cell wall of microorganisms will cause the cell content to depart from the cell and thus, inhibit the cell metabolisms. Severe destructions on the cell may cause the death of the cell.Lysozyme is one of the enzymes that are able to destruct the cell wall of Gram-positive bacteria. An enzyme produced by a bacterium might be able to inhibit the growth of other microbes. There is also a type of antimicrobials that is able to inhibit the formation of cell wall materials. These cells that do not have cell wall are called protoplast. Protoplast is very easily broken, except when placed in isotonic medium. Penicillin and cycloserin are examples of compounds that retard the formation of peptidoglycan in developing cell. Gram-positive bacteria are susceptible to penicillin as they have lots of peptidoglycans.The breaking of plasma membrane and leakage of cell content will inhibit the microorganism growth or even kill the microorganisms. The implication if the cell destruction is the enzymes will not be able to function properly in the cell metabolism. However, antimicrobials that intervene the cell wall permeability are rarely used in food industries (Fardiaz and Betty, 1989). Compounds destructing the protein and nucleic acid are able to destroy cells. This type of destruction is unfixable. For instance, certain amount of alcohol and sodium chloride are able to denaturate the proteins.Those two compounds are often used in food industries (Fardiaz and Betty, 1989). Antimetabolites are the compounds that are similar to natural metabolites. These antimetabolites will interrupt the metabolisms in the cell. The interruption of the metabolisms might retard the cell growth or even kill the cell. Furthermore, the synthesis of DNA and RNA may be inhibited by some antimic robial compounds, namely the compounds that are able to retard the formation of nucleic acid arrangement and compounds that inhibit the nucleic acid polymerization (Fardiaz and Betty, 1989).Plasmolysis or the breakage of a cell is caused by the high plasmolysis pressure. Materials that are often used in food to promote the cell plasmolysis are salt and sugar. Salt and sugar are considered to be able to increase the osmotic pressure in food materials therefore plasmolysis takes place (Fardiaz and Betty, 1989). 2. 4 Antimicrobial Sensitivity towards Microbial Defense Microorganisms have the ability to resist some types of antimicrobial substances. There are two types of resistance in microorganisms toward antimicrobial agents, such as intrinsic or natural resistance and acquired resistance.The antimicrobial agents in intrinsic resistance could not affect the microorganisms, as they have no target sites, which are the microorganisms, to affect. In contrary, in microorganisms that donâ €™t have the intrinsic resistance, the antimicrobial substance could gradually enter the microbial cell and affecting the activity of the microorganisms, as the microorganisms’ cell membrane have lower permeability to antimicrobial substance (Sosa et al. , 2010). Furthermore, in acquired resistance, the microorganisms are naturally vulnerable, as they need specific ways for preventing to be affected by the antimicrobial substances.Some examples of the specific ways are the presence of enzyme that has the ability to inactivate the antimicrobial agent, or alternative enzyme that has the ability to inhibit the activity of antimicrobial agent. Then, it also happens when there is mutation and post-transcriptional and posttranslational in the microorganisms that are the target of the antimicrobial agent. Thus, these will reduce the binding of the antimicrobial agent (Sosa et al. , 2010). Every microorganism has different sensitivity towards different type antimicrobial agents. Coriander (Coriandrum sativum L. is mostly used as seasoning condiment. According to Kubo et al. (2004), in the leaves of coriander, there are volatile oils that are suggested to have antimicrobial properties against food born pathogen, such as Salmonella species, which are gram-negative bacteria. Black pepper (Piper nigrum L. ) is used mostly in food as seasoning condiments. The aqueous and ethanolic extract of black pepper is very effective for inhibiting antibacterial activity agains penicillin G resistant strain of Staphylococcus aureus, Bacillus cereus and Bacillus subtilis (Chaudhry and Tariq, 2006).According to Karsha and Lakshmi (2010) experiment, gram-positive bacteria were more susceptible towards antimicrobial in black pepper than gramnegative bacteria. In gram-positive bacteria, the most susceptible towards antimicrobial in black pepper is Staphylococcus and followed by Bacillus and Streptococcus. Furthermore, among gram-negative bacteria, the most susceptible towards an timicrobial in black pepper is Pseudomonas, followed by E. coli, Klebsiella and Salmonella. Garlic (Allium sativum) is commonly used for antifungal, antiviral, antibacterial, antihelmantic, antiseptic and anti-infamatory.Garlic extract is effevtive in inhibiting the microbial activity of both gram-positive and gramnegative bacteria. Several examples of the gram-negative bacteria are E. coli, Salmonella species and Citrobacter Enterobacter, Pseudomon, Kilabsella) and the gram-positive bacteria are Pseudomonas aeruginosa, Salmonella typhi, Proteus, spp. , Staphylococcus aureus, S. pneumonia Group A streptococcus and Bacillus anthrax (Daka, 2011; Durairaj, 2009). Potassium sorbate is used as preservative in food as the sorbic acid is more effective than benzoic acid in preserving food. The preservation process occurs in higher pH.It is effective to inhibit the microbial activity of Pseudomonas species, which are categorized as gram-positive bacteria (Beuchat, 1980). Mostly, gram-positi ve bacteria are more sensitive towards antimicrobial agent than gram-negative bacteria (Torrence and Isaacson, 2003). 2. 5 Factors Affecting Microorganism Strength towards Antimicrobial Compounds The resistance of microbes towards particular antimicrobial compound is dependent on several factors that contained in that particular microbe such as the cell wall, protein content, nucleic acid, and membrane cell (Lay, 2002).There are several types of microbes that have cell walls, and an antimicrobial compound that can affect the mechanism of the cell wall that influence the microbial resistance. Anti-microbial compounds may interfere with the work of the cell wall as well as peptidoglycan biosynthesis, which is the process in prokaryotic cell wall structure construction. Disruption of peptidoglycan may affect the resistance and sensitivity of microbes to changes in osmotic perspective (Lay, 2002). Microbes also contain nucleic acids.The nucleic acid can be affected by antimicrobial comp unds where the enzymes that are going to be used for the synthesis of nucleic acid are inhibited. The example is rifampin where it binds the enzyme RNA polymerase, quinolone as well as binding enzyme DNA gyrase (Lay, 2002). The resistance of microbes can be affected by the metabolism of the microbes. Enzyme that catalyzes the synthesis of essential molecules can be inhibited by antimetabolite. Antimetabolite is the antimicrobial that is used for inhibiting the growth of microbes. An example of antimetabolite is the sulfinylamide (Lay, 2002).In general, most living cells including microorganisms has the ability to control what is going in and out of the membrane. If there is a rupture in the membrane, it will cause the spillage of the essential inorganic ions. Thus, rupture in the cell membrane can affect the growth and death of the microbes (Lay, 2002). 2. 6 Methods of Microbial Defense towards Antimicrobial Activity 2. 6. 1 Well Diffusion Method Well diffusion method is done by pou ring the microbial suspension that is going to be tested into a sterile Petri dish continued by pouring the media agar into the dish. Then, the Petri dishes are mixed by the eight movement ethod to allow even mixing. The media is then allowed to be solidified and cynlidrical holes are made. The holes are then filled with antimicrobial agents to be tested. The cup was incubated at 37Â °C for two days and then observed on the antimicrobial activity of the tested microbial suspension. Antimicrobial ingredients poured into the well are able to spread evenly as it can diffuse in all directions around the microbial suspension. Once incubated, usually will form a clean circular zone of microbes. This method can be used to test several different types of antimicrobial agents. (Smith, 2005) 2. 6. Kirby Bauer Disc Method One of the easy methods to test the vulnerability of organisms towards the antimicrobial agents is by inoculating the agar with culture and allowing the antimicrobes to diff use to the media agar. The discs that contain antimicrobial agents are placed on the surface of the plate that has the organisms that are going to be tested. At particular distance on respective discs, the antimicrobes will diffuse to a point where the antimicrobes are unable to inhibit the microbial growth. Antimicrobial effectiveness is shown by the inhibition zones. Inhibition zone appears as clean areas that surround the disc.The diameter zone can be measured by using ruler and the result of the experiment considered to be one antibiogram. (Smith, 2005) 2. 6. 3 MIC and MBC The antimicrobial activity can be observed by knowing the concentration of the antimicrobial agents that are going to be used by reducing the total critical number of bacteria that caused their death. MIC (minimum inhibitor concentration) from an antimicrobes can be known by providing the antimicrobial agents into two serial dilutions in series tubes or can be done by well method in a media that has been inocu lated with bacteria.Series tubes that have been filled with antimicrobial agents are incubated to see the growth of the bacteria and the turbidity is observed. The increment in turbidity indicates the growth of the microbes. MIC is the lowest concentration of an antimicrobial agent where the grwoth can be inhibited completely. (Smith, 2005) MBC (minimum bactericidal concentration) is the total number of antimicrobial agents that is required to kill organisms.MBC is done by taking a part from each serial tubes from the MIC that does not show any growth of the bacteria that has been incubated, The samples is taken from respective tubes that has been incubated in pour plate media. MBC is the lowest concentration of antimicrobial agents that are able to kill at least 99. 9% of the inoculums that has been incubated (Smith, 2005). 2. 7 Food Preservatives Preservatives are commonly used to prevent destruction of physical, chemical and microbiological food. Use of antimicrobial preservative s combined with other preservatives so that the preservation of the food will be maximized.According Fellows (2000), the criteria for antimicrobial preservative in food are the usage and is more efficient which when dissolved in water, stable in storage, non-toxic, low antimicrobial concentrations but has a wide range, optimum efficiency at room temperature, non-corrosive, odorless, and its high penetrative ability to the food. Based on its mechanism, the antimicrobial agent acts as the rupture of the cell wall When there is a rupture on the cell wall, the cell contents will spill out thus inhibiting the metabolism of cells. The destruction of the cell wall can result in cell death.Lysozyme can damage the cell walls of Gram-positive bacteria. Penicillin and sikloserin inhibit the growth of peptidoglycan in the cell develops. Gram-positive bacteria is sensitive towards penicillin as the high level of peptidoglycan content. Damage to the cell wall would also cause damage to the plasma membrane (Fellows, 2000). NaCl and alcohol is often used to preserve food because it can cause denaturation of proteins and nucleic acids that can destroy the cell and cannot be repaired. While H2O2 is an antimicrobial that can destroy the enzyme activity of microbes.Compounds inhibiting the formation of nucleic acids and nucleic acid polymerization inhibitor compounds can inhibit the synthesis of both DNA and RNA. The use of salt and sugar can cause plasmolysis the microbial cell. Since the osmotic pressure on microbial too high, so that the cells undergo plasmolisis and can inhibit the growth of microbes (Fellows, 2000). Ascorbic acid can inhibit the growth of bacteria and molds in a way to inactivate the enzyme fatty acid dehydrogenase. Ascorbic acid can work optimally at a pH above 6. 5.Propionic acid is at its most effectiveness to inhibit molds and yeasts with maximal activity at pH above 5. Acetic acid as vinegar used to preserve bread in order to prevent mold contamination, but vinegar cannot inhibit the growth of yeasts. Acetic acid work optimally at low pH (acid). Ethylene oxide and propylene oxide can be used as a fumigant in spices and flour. Sodium or potassium nitrite and nitrate are commonly used for preservatives in meat products. Maximum working power of nitrite compounds is pH of about 57. Nitrite also serves to inhibit Clostridium botulinum, Acinetobacter, Moraxella, Flavobacterium,Pseudomonas, Enterobacter, Escherichia, and some micrococcus. Nitrites are heated simultaneously with foods will provide the growth inhibitory effect against microbes ten times greater than that of nitrite without heating (Fellows, 2000). CHAPTER III MATERIALS AND METHOD 3. 1 Materials and Equipments Equipments that are used in the experiment are balance, blender, grater, dilution bottle, autoclave, waterbath, refrigerator, vernier caliper, tip with the cuttop, sterile toothpicks, sterile petri dishes, micropipette, tip (10 ml and 100Â µl), and Bunsen’s b urner.Materials that are used are spices (black pepper, garlic, and coriander), potassium sorbate, alcohol, aquadest, bacteria culture (Bacillus subtilis), yeast culture (Candida tropicalis), mold culture (Aspergillus oryzae), PCA media, and NA media. 3. 2 Procedures 3. 2. 1 Extract Preparation 1. Spices were weighed up to 3 grams and reduced in size. 2. The spices were mixed with 10mL of ethanol into Erlenmeyer flasks. 3. 2. 2 Antimicrobial Assay 1. 1mL of culture is added into Petri plate 2. The matching medium is added into the Petri plates (NA for B. subtilis and PDA for A. ryzae and C. tropicalis) 3. The media were let to solidify. 4. Holes were made by using tips with cut-tops. 5. Mixtures of spices were added into the holes. 6. The plates were incubated were incubated for 48 hours in 37? C. CHAPTER IV RESULTS AND DISSCUSION 4. 1 Effect of Antimicrobial Compounds Towards Microbial Growth 4. 1. 1 Garlic Table 4. 1 Observation result of inhibitory activity by garlic From Table 4 . 1, it can be seen that the microorganism that was the most susceptible to allicin contained in garlic, judging by the largest area inhibition, was Bacillus subtilis.There were even no growths in some Petri dishes that meant that the effectiveness of allicin as the antimicrobial compound could be found most when it was applied for bacteria, which was Bacillus subtilis in particular. It matched with the previous literature discussed stating that allicin is an active compound in garlic that attacks the cell membrane in microorganism. However, there was an error found in the experiment from Group 4, which resulted in no inhibition found from Bacillus subtilis. This might happen due to the absence of the allicin itself or the ontamination happened which might result in the building of the resistance towards antimicrobial compound. Afterwards, it can be seen from the experiment that Candida tropicalis and Aspergillus oryzae shared almost the same result, which means that they were also susceptible to allicin. The uneven inhibition found in Candida tropicalis showing the largest inhibition (7. 23mm) beyond the inhibition done for Bacillus subtilis might happen because of the uneven diffusion of the active antimicrobial compound to the dishes. It still matched the theory since allicin has antibacteria and antifungal activity towards the species mentioned above.From the result, it can be concluded that garlic can be used as the antimicrobial compound in food to prevent foodborne disease and food poisoning. However, the concentration of garlic has to be concerned since it has strong odor and may be unpleasant to some people. 4. 1. 2 Coriander Table 4. 2 Observation result of inhibitory activity by coriander From Table 4. 2, it can be seen that coriander is found to be effective as an antimicrobial compound most in Bacillus subtilis, although some of the dishes showed no area of inhibitions.The disappearance of Bacillus subtilis in most of Petri dishes shown by no grow th sign indicated that coriander worked best to inhibit bacteria. This result matched with the previous literature stating that coriander inhibits food pathogenic bacteria, especially Gram-positive bacteria. However, coriander has the least inhibition activity towards Candida tropicalis and Aspergillus oryzae was found to be less susceptible to the volatile compound in coriander acting as antimicrobial compound. There were almost no area of inhibition found in every petri dish, proving that coriander did not affect mold and yeast.Since the literature stated that coriander has almost no antifungal activity and its activity toward yeast has not been examined, the result matched them. 4. 1. 3 Black Pepper Table 4. 3 Observation result of inhibitory activity by black pepper From the result of the experiment, it can be seen that black pepper is most effective when used against Bacillus subtilis, as many bacteria were inactivated, indicated by the area of clear zone, which in some plates, all of them doesn’t grow at all and so the area of clear zone can’t be measured.Aspergillus oryzae are quite susceptible as well to black pepper’s antimicrobial compound as the area of inhibition overall is large. While the most resistant microorganism from the experiment shown is Candida tropicalis, as the area of inhibition is relatively small. From the theory, black pepper shows antimicrobial activity against bacteria, molds, and yeasts, but the strongest towards bacteria, especially Grampositive bacteria. The result of the experiment matches the theory, as black pepper is very effective in stopping the growth of Bacillus subtilis, which is a Grampositive bacterium.It also inhibited the growth of Candida tropicalis and Aspergillus oryzae, so the result of the experiment matches the theory. 4. 1. 4 Potassium Sorbate Table 4. 4 Observation result of inhibitory activity by potassium sorbate From the result of the experiment, it can be seen that potassium sorbat e is very effective in stopping the growth of Bacillus subtilis, as in some plates it inhibited the growth of all the bacteria and so the area of clear zone can’t be measured. Antimicrobial activity can be seen as well towards Candida tropicalis and Aspergillus oryzae.According to the theory, potassium sorbate is very effective when used to inhibit the growth of bacteria, molds, and yeasts. The result of the experiment matches the theory, as potassium sorbate in this experiment is able to stop the growth of Bacillus subtilis, Candida tropicalis, and Aspergillus Oryzae. 4. 2 Microbial Defense Towards Antimicrobial Compounds 4. 2. 1 Bacteria (Bacillus subtilis) Table 4. 4 Table of diameter of inhibition zone of Bacillus subtilis in some condiments From the table 4. 4, it is shown that the most effective condiment in affecting the microbial defense of the Bacillus subtilis for its growth is arlic. Also, the least effective condiment for inhibiting the growth of Bacillus subtilis is coriander. According to the theory, garlic is effective for both Gram-negative and Grampositive bacteria, thus the inhibition zone is larger. Also, coriander is effective in inhibiting Gram-negative bacteria, as in the experiment the bacteria used was Gram-positive bacteria, thus, coriander is not effective in inhibiting Bacillus subtilis. The experiment result has shown the same result as the theory given. 4. 2. 2 Yeast (Candida tropicalis) Table 4. 5Table of diameter of inhibition zone of Candida tropicalis in some condimentsIn the table 4. 5, it shown that the most effective condiment in affecting the microbial defense and microbial growth of Candida tropicalis is garlic and the least effective is coriander. According to the theory, garlic is used as antifungal and is the most effective one in inhibiting the growth of bacteria, molds and yeast. Thus, the inhibition zone of garlic is the largest. Also, as coriander is mostly effective in inhibiting Gram-negative bacteria, the rate of inhibition of yeast is lower, so the inhibition zone is smaller. The experiment result has shown the exact result as the theory given. 4. 2. Molds (Aspergillus oryzae) Table 4. 6 Table of diameter of inhibition zone of Aspergillus oryzae in some condiments The experiment result has shown that the most effective condiment towards the inhibition zone in Aspergillus oryzae media is garlic and the least effective condiment is coriander. Referring to the theory, garlic is mostly used as antifungal and the most effective condiment used in the experiment to inhibit the growth of bacteria, mold, and yeast. Also, coriander is least effective in inhibiting the growth of Aspergillus oryzae as coriander is most effective in inhibiting gramnegative bacteria.In conclusion, the result of the experiment shows the same result as the theory given. CHAPTER V CONCLUSION Spices have different antimicrobial compounds able to inhibit the growth of various types of microorganisms. Based on the expe riments, garlic, coriander, and black pepper have the most effective activity in inhibiting the growth of bacteria, or in this case Bacillus subtilis. However, coriander was proven to have no antifungal activity by the absence of inhibition zone on the Petri plates with yeast and molds, in this case Candida tropicalis and Aspergillus oryzae.In addition, potassium sorbate is effective to inhibit the growth of all types of micoorganisms in the experiment: bacteria, yeast, and molds. The Bacillus subtilis bacteria, Candida tropicalis yeast, and Aspergillus oryzae molds are most susceptible by the presence of garlic. This means that the garlic has the highest effectiveness in affecting the defense of bacteria, yeast, and molds. In contrast, the growth of bacteria, yeast, and molds is least affected by the presence of coriander.

Segmentation

Segmentation We believe that the marketing segmentation of Lee Kum Kee’s soy sauce is a mixture of demographic, psychographic and benefit segmentation. Since customer’s buying motives comes from their own habit and their own lifestyle before they consume soy sauce as they will use the same brand or the same soy sauce when they find that soy sauce is what they want and they need.Demographic segmentation  consists of dividing the market into groups based on variables such as age, gender family size, income, occupation, education, religion, race and nationality. Lee Kum Kee takes care about the minority with different religion, Lee Kum Kee establishes different labels to show whether that kind of soy sauce is suitable for them or not. For example, Lee Kum Kee recommends the Double Deluxe Soy Sauce to the Kosher as the ingredient of this soy sauce is conformed to the rules of Jewish religion.Psychographic segmentation is a method of dividing markets on the bases of the ps ychology and lifestyle habits of customers. Lee Kum Kee cares those people with different lifestyle, such as, people who concern much about their health and the vegetarian. For example, Lee Kum Kee has produced Salt Reduced Light Soy Sauce for those who concern their health much. Also, Lee kum Kee has recommended some kinds of soy sauce for the vegetarian to use.Benefit segmentation is A  form  of  market segmentation  based on the differences in specific  benefits  that different  groups  of  consumers  look for in a  product. Lee Kum Kee has provided lots of products to satisfy different needs of the people including those who affected by the demographic and psychographic factors. Apart from the above mentioned, Lee Kum Kee endeavors to provide a larger product variety. Recently, Lee Kum Kee introduces a new soy sauce without adding any MSGs. Targeting

Bill Clinton Essay Example | Topics and Well Written Essays - 750 words

Bill Clinton - Essay Example ed States because the US enjoyed a relatively high prosperity during his term progressive laws such as State Children’s Health Insurance Program and agreements such as North American Free Trade Agreement or NAFTA. Because of these achievements, he ended his term with one of the highest approval rating of all times. His presidency however was tainted with a scandal involving an intern named Monika Lewinsky between the period 1998-99 that led to an impeachment trial initiated by the House of Representatives and later acquitted by the Senate (www.infoplease.com, nd). The started by the was filed by Paula Corbin Jones on May 6, 1994 in the United States District Court for the Eastern District of Arkansas when he allegedly made sexual advances to her when he was still a governor of Arkansas. Judge Susan Webber Wright however decided in favor of President Clinton on April 1, 1998 and a settlement was made on November 13, 1998 (infoplease.com, nd). The lawyers of Ms. Jones again presented witnesses to the lawyers of President Clinton to continue the allegations against the President’s pattern of deceit. It was alleged that Monika Lewinsky had sexual relationship with the President. Among the witnesses presented was Monika Lewinsky whose name was presented by Linda Tripp a confidant of Monika Lewinsky who was also a White House staff. Tapes of various conversations relating Monika Lewinsky’s contracts with the President was presented. Monika Lewinsky’s lawyers however issued a sworn statement on her behalf in which she asserted that she had never had a sexual relationship with the President. To quote the affidavit; I have never had a sexual relationship with the President, he did not propose that we have a sexual relationship, he did not offer me employment or other benefits in exchange for a sexual relationship, he did not deny me employment or other benefits for rejecting a sexual relationship (Rutgers University, 2014). For his part, President

The Definition and Knowledge on Youth Culture Research Paper

The Definition and Knowledge on Youth Culture - Research Paper Example Today, the youth engage in too much activity and have access to a lot of information that they refrain from following the advice of their elders; in fact, they believe they are old enough to make their own decisions even at early stages of adolescence (Harvey 228). As a result, the culture of the youth has vastly changed over a short period as compared to customary practices when people had to attain self-sufficiency and follow the right path in order to survive. Assertively, this essay entails a comprehensive assessment of facts supporting the notion that the culture of the youth continues to change over time. These facts will be a general evaluation of the journey from adolescence to adulthood that dictates the culture that the youth adopt. Significantly, the youth culture was not a topic of discussion until late in the 20th Century where it became a historical phenomenon based on an evaluation of past practices relative to the adolescence to adulthood experience. Since then many p rofessionals have come up with theories on the evolution of the youth culture based on the core influential factors i.e. history, economy and psychological traits. According to some of these theories, the changes in youth culture emanated from the introduction of schools as a compulsory way of education. The overall idea is that this isolation of the youth created a completely new experience of the adolescence to adulthood mostly because it led to limited interactions with adults. Contrary, problems such as those identified in the ‘How Long Will I Cry?’

AIDS Essay Example | Topics and Well Written Essays - 1500 words - 1

AIDS - Essay Example The virus is spread by unprotected sex between affected individuals and through shared needles when used for hypodermic infections. Inadvertent transfusion of blood from a suffering person to a healthy person can also transmit the virus. However there are skeptics who claim that the AIDS virus was intentionally developed in a secret military program in the United States as a means of biological warfare to curb world population (Mazza J., 2005). In a controversial article, the author debates the unlikelihood of the accepted theory of a green monkey biting an African native, thereby transmitting the virus to humans and provides an argument in favor of the biological warfare theory and the subsequent creation of this virus in a laboratory. Nevertheless, whatever the origin, AIDS is now a worldwide phenomenon and the subject of intensive research for getting the human population rid of this deadly malady. As far as the United States is concerned, it is believed that almost one million people are living in this country with HIV infection and it has spread to all the states and to all sectors of society (www.avert.org). Half a million deaths have occurred due to HIV infection but the statistical data is not comprehensive as it is based on reports of AIDS diagnosis. The American Centre for Disease Control and Prevention (CDC) data till 2006 suggests that 448,871 people suffering from this disease were living in America. The ethnic data suggests that the black people are the ones leading the group in terms of people affected as they accounted for 44% of the cases with the white majority close at heels with a figure of 35%. The Hispanic population of America suffered at a rate of 19% and the rest 1% were from other races (www.avert.org). Figures of adults and adolescents above the age of 13 years, who were living with AIDS in the USA till 2006, show that in majority of the cases (59%),

Leadership and change Essay Example | Topics and Well Written Essays - 2500 words

Leadership and change - Essay Example Transformational leaders have the capability to encourage others, supporting their followers to respect and trust them. Companies require leaders who are capable of coping with this massive change, maintain day to day functions, and offer a competitive gain even at the time of downsizing. Transformational leaders can motivate and encourage their followers, uniting them for a combined cause, causing better productivity, performance, as well as job significance. The second section - Literature Review - will highlight the theories and concepts of transformational leadership. Third section will explain why transformational leadership is the appropriate approach to adopt at the time of downsizing. Fourth section will discuss the limitations of this leadership approach. Fifth section will reflect on the needs to develop the appropriate leadership skills, and sixth chapter will conclude the paper by providing the summary of the findings. The theory of transformational leadership has its origins with leadership scholar James MacGregor (Bass & Riggio, 2012). He presented the preliminary framework for the theory of transformational leadership by recognizing what he believed two opposed aspects - transactional leadership and transformational leadership (Bass & Riggio, 2012, p. 102). In transactional leadership, leaders keep a rapport with their team as a series of â€Å"exchanges or bargains† (Avolio & Yammarino, 2013, p. 82) to satisfy existing requirements. Transformational leadership bypasses the conventional form of exchanging incentives and attains preferred performance by intellectually motivating, and encouraging followers to go beyond their self-interests for a better mutual objective. Leadership has exceeded beyond the basis of simplifying the necessary performance of staff to boost the value of the productivity. Kearney & Gebert (2009) significantly developed

The influence of payment cards on currency demand in United Kingdom Essay

The influence of payment cards on currency demand in United Kingdom (2001-2010) - Essay Example There are many things that can be seen when the major effects of money demands are debated with the use of empirical analysis. These factors have a clear impact over how things work in the economic terms around the globe. The modern world is the new place for investing money in new things, and when money is to be invested, a lot of research and analysis is required to base the decision upon. There are many factors at play, with a great many implications that need to be considered. For this reason, factors like increasing globalization, along with other things like growth in capital markets, as well as the ever changing (yet flexible) forex exchange rates, are playing a very important role for the many people who are making new discoveries in the already present literature. Most of the time, money bankers and other analysts are not focusing their attention on the major factors that drive business on an international basis; however, with the presence of these factors, these researchers and analysts are paying all due attention towards central banks, their powers, and the factors which have an impact on them to understand money demand analysis.. Making a demand for money is not the only thing that is being put into account; however, these analyses and estimations about money demands can also be problematic. Studying such analysis is not always an easy job. Investment of money cannot always provide anyone with good returns. Demand and supply rules are the basics of any economic system and of trading. Same goes for money as well. For this reason, you are taking money into account when you consider the different routes for money to change hands. Hence, you can take cash or bank deposits into the equation. In short, money could be M1, M2 or M3, depending on t he situation. There are other terms which are regularly given to accommodate the flow of money into an economy. When you consider interest-bearing assets, then the M1 can be given the definition of store of value, and when transactions are done, then the M1 will be denoted as the liquidity. Hence, the fine line between transactions and interest-bearing assets can be taken into account. Thus liquidity can help money rotation while interest amount can take care of the other factors. There is a great deal of demand when the other major things are considered, and for this reason, the capitalist society [believes that the formation of a person’s wealth should be given utmost importance. Hence, in the bigger economies or the macro-economies, holding of wealth is usually not equal. This creates transaction motives and asset motives. Further classifications can also show the micro-economic

Government of Zanzibar v British Aerospace Essay

Government of Zanzibar v British Aerospace - Essay Example In the case, the Government of Zanzibar had contracted with British Aerospace (supplier) in order to purchase an executive jet from the company. As part of the deal, the Government of Zanzibar entered into a separate contract with a financing company that eventually bought the plane before leasing it back to the government. However, the plane was soon found to be defective. It was returned back to British Aerospace for repair but the faults persisted even after the repair. The Government of Zanzibar immediately stopped its payments of the semiannual installments to the financing company. In order to recover their costs, the financing company (CIBC) took possession of the plane and sold it. The Government of Zanzibar then initiated an action against British Aerospace either to rescind the contract or alternatively be awarded damages under the British contract laws.Additionally, the government of Zanzibar accused the supplier (British Aerospace) of false representation in the contract for having claimed that the Jet was airworthy, reliable and without any construction or design defect. They also appealed to rescind the contract and put them back to the pre-contractual position. For example, it could be by returning plane to the Government in its original position or compensation for damages due to misrepresentation. This was particularly because the government claimed that the contract with British Aerospace is subjected to fraudulent misrepresentation (deceit).

Critically Analyse the Claim that Humans Are Political Animals Essay

Critically Analyse the Claim that Humans Are Political Animals - Essay Example This paper stresses that given the fact that individual human beings are not in any position to carry out their naturally defined functions without the city-state, the so given state is therefore naturally precedes the individuals in every aspect. In regards to the above mentioned arguments then, it is clear that every human being or individual has the natural impulse for a community which is political especially with the consideration that the city-state was created out of the intelligence of human beings. They then end up living a political life while in nature they are animals. Man is known to have an innate proclivity to always participate in several public activities and deal with others in the city. Associations and other bonds are then created as men live together in partnership due to the natural tendency to interact and socialize with other men. This rpeort makes a conclusion that as much as the several theorists try to explain the political naturalism in human beings, there is no concern or any consideration expressed on the part of the city-state’s modern liberalism. There is no explanation given on the freedom of individuals who participate in the city-state and protective provisions for their own private life from the exposition of the entire public. Aristotle’s arguments and justification on communitarian politics gives priority to the well-being of a community. Other modernists also argue on the basis of humans being conjugal and dependent on each other and thus conclude that establishing households, interacting and socializing among individuals makes one a complete human being. In that case, individual liberty does not win in context of any city-state just as freedom and private ownership does not exist for animals.