1. Introduction

Background Research

It is known that our skin flora are home to many numerous types of bacteria, but the most commonly found bacterial species found on the skin is the Staphylococcus and Streptococcus species.

The Staphylococcus species especially, causes disease through the infection of tissues found on the body and although over 30 different types of Staphylococci can infect humans, most infections are caused by Staphylococcus aureus. (Stoppler, Shiel Jr, 2012) The Staphylococcus aureus can cause skin infections such as impetigo, which starts as tiny blisters that break and expose moist, red skin. After a few days, the infected area is covered with a grainy, golden crust that gradually spreads at the edges (Gardner, 2013), Cellulitis, in which the infected area will be warm, red, swollen, and tender. It eventually results in a fever, chills, and swollen glands (WebMD, 2011). Methicillin-resistant Staphylococcus aureus, known as MRSA, is also resistant to the antibiotic methicillin and other drugs in the same class, including penicillin, amoxicillin, and oxacillin. (Stoppler, Shiel Jr, 2012) However, research has been done that has shown that certain fruits possess certain compounds which cause staphylococcal growth inhibition. An example is the common walnut, research done showed that extracts of the immature fruit resulted in biofilm adherence and formation of the Staphylococcus aureus as well as the inhibition of staphylococcal growth. The walnut tree is rich in phenolic compounds as well as naphtoquinones and flavonoids, which the researchers believe are the reason for the the growth inhibition as well as the biofilm adherence and formation. (L. Quave, R.W. Plano, Pantuso, C. Bennett, 2008) Other fruits such as chokeberry, blueberry, elderberry and black currant were also found to have flavonols and phenolic acids among other compounds (Jakobek, Seruga, Novak, Medvidovic-Kosanovic, 2008) which could possibly lead to similar anti-bacterial activity like that of the walnuts.

As for the Streptococcus species, there are more than 20 different types of strep bacteria, which are split into two main groups, Group A Strep and Group B Strep. (NHS Choices, 2013) Group A Streptococcus bacteria is usually found on the skin and in the throat. While Group B Streptococcus bacteria can usually be found in the vagina area. Minor Group A Strep infections usually causes pharyngitis, impetigo, cellulitis and sinusitis. While more major Group A Strep infections result in pneumonia, sepsis and meningitis and in more severe cases, necrotizing fasciitis. However, these can only occur when the bacteria enters the tissues and organs of the body resulting in something known as an invasive infection. Streptococcus pyogenes, often referred to as group A Streptococcus bacteria (Encyclopaedia Britannica, 2013), can cause these infections in humans. Minor infections such as strep throat can be cured through the use of medicinal herbs, and many herbs such as the enchinacea, contains different compounds, including polysaccharides, oils, and antioxidants known as flavonoids (Adam Cloe, 2011), which are also found in walnuts and was also useful in the inhibition of Staphylococcal growth as well as biofilm adherence.

However, in more major infections such as necrotizing fasciitis, such herbs will probably not suffice although the root of the infection is still the Streptococcus pyogenes. In necrotizing fasciitis, there are 3 general variations of necrotizing fasciitis classified as such due to the different types of bacteria that causes it. In Type II necrotizing fasciitis, Streptococcus pyogenes is the cause of this. Necrotizing fasciitis causes rapidly spreading infection, usually located in fascial planes of connective tissue that results in tissue death. Patients with necrotizing fasciitis have an ongoing medical emergency that often leads to death or disability if it is not promptly and effectively treated. (Stoppler, 2012). Therefore, it is imperative to prevent such diseases from occurring by destroying or trying to destroy the Staphylococcus and Streptococcus strains found on the body. Many fruits and plants contain compounds that are able to kill these bacteria. Herbs such as garlic, echinacea, aloe, eucalyptus and oregano have also been proven to have antibacterial properties. For example, the aloe vera’s leaves are filled with a medicinal gel that is rich in complex polysaccharides, amino acids and salicylic acid, and it has antibacterial, anti-inflammatory and immune-stimulating properties (Contursi, 2011) which can be rubbed onto skin Staphylococcus infections. Eucalyptus as well as Oregano were shown to have remarkable action on Staphylococcus aureus as well as the Methicillin-resistant Staphylococcus aureus strain.

However these are all just essences of fruits and herbs that have shown that they are effective in the inhibiting or the killing of only specific bacteria. There many more species of bacteria such as Staphylococci, Streptococci as well as Corynebacterium such as Propionibacterium acnes. They are generally nonpathogenic and considered to be commensal, although mutualistic and parasitic roles have been assigned to them (Todar, 2012) Therefore methods such as hand sanitizers have been employed which are able to kill almost all types of bacteria found on the skin. Hand sanitizers usually consist of an active ingredient to kill bacteria, which is usually an alcohol, humectants, which are moisturizing ingredients that counteract the drying effect alcohol can have on the skin (Lohrey, 2010) and emulsifiers which binds the ingredients together to prevent the ingredients from separating. Ethanol is usually used as an active ingredient and The American Society for Microbiology reports that alcohols destroy bacteria by causing membrane damage and denaturation of proteins. Ethanol also prevents the spread of microbes by interfering with cell metabolism and cell division. (Palacios, 2010) Isopropyl alcohol or isopropanol and triclosan are also effective ingredients in hand sanitizers that kill bacteria, isopropanol is said to be effective against bacteria as well as viruses, triclosan is also particularly good at at destroying gram-positive bacteria, according to the American Society for Microbiology. (Palacios, 2010) Well known genera such as Staphylococcus, Streptococcus, Enterococcus, (which are cocci) and Bacillus, Corynebacterium, Nocardia, Clostridium, Actinobacteria, and Listeria (“Gram-positive bacteria”, n.d.) are also gram-positive bacteria, allowing the triclosan to be especially effective in killing them.

However, there are the advantages to using more natural methods such as walnut essence which has been found to inhibit bacterial growth. Fruits such as bananas contains vitamins B and C and is a rich source of potassium. This tightens, softens as well as tones the skin. They can also restore the natural oils found on the skin as well as prevent cell oxidation and wrinkles. Mango pulp can be applied on the face to keep the skin soft and supple. It is an anti-oxidant and used regularly, it can reverse oxidation damage. Just like bananas and lemons, oranges also contain Vitamin C and raw orange and lemon peels can be rubbed on the nails to remove discolouration. Orange peels rubbed regularly on the hands can help to lighten skin colour and also tighten the skin. (D’costa, 2013) Peaches, are also especially good for dry skin as they not only moisturise the skin but also leaves it supple and soft. (TNN, 2012) These are just a few of the many benefits that fruits can bring when applied onto the skin or consumed. Therefore this shows that not only can fruits inhibit and kill bacteria, it is also useful for nourishing the skin, perhaps a better alternative in the future.

Research Question

An investigation on how acids in fruits affect the amount of bacteria on the iPhone.

Hypothesis

Acids in raspberry will kill the most amount bacteria found on the two parts of the iPhone

Independent Variable

Different types of fruits (Nectarine, Peach, Avocado, Raspberry)

Dependant Variables

Bacteria on parts of the iPhone (Black screen area and Speaker area) (1 swab but repeat 3 times)

Constants

• Time for the bacteria to incubate
• Amount of mixture extracted for each different segment
• Amount of dilution

Hypothesis The citric acid in raspberry kills the most bacteria found on the iPhone screen. (Natural Acids of Fruits and Vegetables, n.d.)