**2.1 Bacteria**

Bacteria are small microorganisms that can grow in an ideal condition. They split and multiply so quickly [6]. Harmful bacteria, called pathogen, are recognized as hazards in safety of food. Therefore the spread and incidence of them must be controlled in food. The common sources for bacterial growth and further distribution are the air, human body, dust, pets and pests, row food (meat, milk, vegetable, etc.), soil, kitchen/factory instruments, food handlers and cloths/hands. The extrinsic factors that provide optimum conditions for bacteria to survive include food (especially protein), water (water activity), oxygen, temperature, and pH level [7]. The control of these factors can result in well preservation of food [8]. **Table 1** is illustrates major bacteria and their risks.


**7**

**Table 3.**

**3. Chemical contamination**

*The major parasites and their risks.*

*Food Contamination*

**2.2 Viruses**

**2.3 Parasites**

**Table 2.**

Parasites and their risks.

*The major viruses and their risk.*

**Major viruses Risk contamination** Hepatitis A virus Fever, abdominal discomfort

Rotavirus Vomiting, watery diarrhea, fever, abdominal pain

weightloss *Entamoeba histolytica* Dysentery (severe, bloody diarrhea)

**Major parasites Risk contamination**

*Ascaris lumbricoides* Intestinal, lung infection *Diphyllobothrium latum* Attaches to intestinal wall

*Taenia solium* Attaches to intestinal wall

*Anisakis* spp. Anisakiasis

*Cryptosporidia* Respiratory, gastrointestinal illness

*DOI: http://dx.doi.org/10.5772/intechopen.89802*

Viruses are very tiny organisms that can grow and survive only in a host cell. They are able to enter food and water due to poor hygienic conditions. Viruses can also be found in people who disrespect hygienic practices [9]. Viruses can only multiply and grow inside a living cell. They are very resistant to heat, drying, freezing, radiation, etc., and are also able to survive for a long time in food or environment. Viruses can enter food during processing, transportation through person to person contact [10]. The awareness about the importance of viruses as food contaminants would result in good hygiene practices done by consumers to minimize the transmission of viral illnesses [2]. **Table 2** shows the major viruses and their risk.

Parasite including worms and protozoa can enter food or water. They can also infect people through these ways. They need ambient environment and proper hosts to survive. Contamination of food occurs by fecal due to poor personal hygiene of food handler, improper disposal of human feces, improper sewage treatment and utilization of untreated sewage for crop culturing [3, 11]. **Table 3** shows major

Norwalk virus Nausea, vomiting, diarrhea, abdominal pain (gastroenteritis), headache, low-grade fever

*Giardia lamblia* Diarrhea, abdominal cramps, fatigue, nausea, flatulence (intestinal gas),

*Trichinella spiralis* Intestinal wall, enter the blood (to feed on it) and lymphatic system *Toxoplasma gondii* Neurological disorders, particularly schizophrenia, bipolar disorder

Chemical contaminations of food are another human concern that involves numerous substances such as: agrochemicals, veterinary medicines residues, pesticides residues, environmental contaminants, heavy metals, persistent organic

#### **Table 1.**

*The major bacteria and their risks.*
