**Food Poisoning:**

To cause food poisoning, a large amount of food-poisoning bacteria typically needs to be present in the food. However, under suitable conditions, bacteria can multiply rapidly.

These conditions include:  
- **Time:** Under ideal conditions, one bacterium can multiply into 2,097,152 bacteria in 7 hours.  
- **Temperature:** Food-poisoning bacteria grow best between 5ºC and 60ºC, a range known as the "Danger Zone." Foods should not be kept within this temperature range.  
- **Nutrients:** Bacteria require specific nutrients to grow and multiply. Preferred foods include dairy products, egg products, meat, poultry, fish, and shellfish. Because bacteria grow rapidly in these foods, they are considered high-risk. High-risk foods contaminated with food-poisoning bacteria (such as meat, fish, poultry, and seafood) can poison anyone who consumes them if kept in the danger zone.  
- **Water:** In environments without water, bacterial growth slows down or stops. Drying is an effective method of food preservation.  

Individuals at high risk of food poisoning include pregnant women, children, the elderly, and those with weakened immune systems.

**How Does Food Contamination (Cross-Contamination) Occur?**  
Food contamination occurs due to inadequate storage, preparation, and processing, and poor personal hygiene of those who prepare and serve food. Food-poisoning bacteria can be found everywhere: in soil, on animals, and in humans. Raw meat, poultry, and vegetables naturally carry these bacteria. When raw foods come into contact with ready-to-eat foods, bacteria from the raw foods can be transferred. This is known as cross-contamination.

Cross-contamination is a common way for bacteria to spread to food. It can occur in two ways:

1. **During Food Preparation:** Bacteria from raw foods can be transferred to hands, utensils, and equipment such as cutting boards. If these items are later used to prepare ready-to-eat food (e.g., salad) without thorough washing, bacteria from the raw food can contaminate the ready-to-eat food. If these foods are not cooked afterward, the bacteria will not be destroyed before consumption.

To prevent such contamination from cutting boards:  
- Use different boards for raw and ready-to-eat foods. Using different colored boards can help avoid confusion (e.g., red for raw foods, green for ready-to-eat foods).  
- Clean and sanitize the board after working with raw food before using it for ready-to-eat food.  

2. **During Storage:** If ready-to-eat foods are not stored separately from raw foods, bacteria can transfer from the raw foods to the ready-to-eat foods. If stored in the same refrigerator, raw foods should be kept on the lowest shelves and ready-to-eat foods on higher shelves to prevent liquids from dripping onto them. Foods should also be stored in washable, non-toxic, and covered containers.

**How to Prevent Food Poisoning?**  
To prevent food poisoning:  
- Prevent (cross) contamination of food.  
- Prevent bacterial growth and multiplication.  

Food poisoning can be thought of as a result of a chain of events:  
- Bacteria must be present in the food.  
- To grow, bacteria need the right temperature (5ºC - 60ºC), moisture, and nutrients.  
- Bacteria need time to grow and multiply.  
If this chain can be broken, food poisoning can be prevented.

For example:  
- Wash hands thoroughly before touching food.  
- Wash all tools, utensils, and equipment used in preparing raw foods thoroughly with hot water and detergent.  
- Store raw foods below cooked foods in the refrigerator.  
- Store foods correctly to avoid the Danger Zone.  
- Consume foods as soon as possible.  

**Common Food-Poisoning Bacteria:**

- **Salmonella:**  
  - Commonly Found In: Meat, poultry, eggs, and egg products.  
  - Symptoms: Nausea, stomach cramps, diarrhea, fever, and headache.  
  - Effect: 6-72 hours after consumption.  

- **Bacillus:**  
  - Commonly Found In: Cereals, rice, meat products, and packet soups.  
  - Effective Amount: 108 spores/g.  
  - Symptoms: Nausea, vomiting, diarrhea, and stomach cramps.  
  - Effect: 1-6 hours after consumption, lasting no more than 24 hours.  
  - Note: This bacterium produces spores that do not die during cooking. Leaving cooked food in the Danger Zone can cause these spores to produce toxins in the food.  

- **Staphylococcus aureus:**  
  - Commonly Found In: Meat and poultry dishes, egg products, mayonnaise-based salads, cream, and creamy desserts.  
  - Effective Amount: 0.5-1 μg.  
  - Symptoms: Acute vomiting, nausea, sometimes diarrhea, and cramps.  
  - Effect: 30 minutes to 8 hours after consumption, lasting no more than 24 hours.  
  - Note: This bacterium produces toxins in the food that are not destroyed by cooking. Therefore, proper storage of food before and after cooking is crucial. This bacterium is often found in the mouth, nose, or skin of humans. Thus, maintaining high levels of personal hygiene for food handlers is essential. Workers with cuts or wounds on their hands or arms should completely cover them with waterproof bandages, change them frequently, and wear disposable gloves if the cut/wound is on the hand.  

Other common food-poisoning bacteria:  
- Clostridium perfringens  
- Vibrio parahaemolyticus  
- Listeria monocytogenes  

**Diseases Caused by Foodborne Pathogens:**  

- **Salmonella spp. (Acute Enterocolitis):** Incubation: 6-48 hours, Duration: 1-7 days.  
- **Escherichia coli (Diarrhea):** Incubation: 1-10 days, Duration: 1-7 days.  
- **Escherichia coli (O157:H7) (Hemorrhagic Colitis, "Hamburger Disease"):** Incubation: 3-4 days, Duration: 3-7 days or longer.  
- **Staphylococcus aureus (Diarrhea, vomiting due to toxins in food):** Incubation: 2-4 hours, Duration: 6-24 hours.  
- **Clostridium perfringens (Diarrhea due to intestinal toxins):** Incubation: 6-48 hours, Duration: 24-48 hours.  
- **Bacillus cereus (Diarrhea, vomiting due to toxins in food):** Incubation: 1-24 hours, Duration: 12-24 hours.  
- **Vibrio parahaemolyticus (Watery diarrhea, cramps):** Incubation: 4-30 hours, Duration: 2-5 days.