Cooking 101: Sanitation

July 22, 2008

This post is part of a series called Cooking 101, which introduces the basics of cooking. The series follows the book Culinary Fundamentals. Check out the previous posts here.

Unit 3: Sanitation

Sanitation - everyone’s favorite topic, right? I know, it’s not exciting but I thought I’d run down some of the basics and add in a few tips from the the book. Then, next week we can move on to basic food science in Unit 4.

Pathogens

Pathogens are the tiny, invisible organisms that make you sick - and they love your food. Here are the different kinds and how you can get rid of them:

• Bacteria - These are single celled organisms and can grow incredibly quickly. Some are harmful while others are not. Different types of bacteria like different conditions: some like the cold and are destroyed by heat, while others like the heat and are destroyed by cold. Still others like moderate temperatures. The same variety holds true for oxygen conditions. Some bacteria thrive with oxygen and some are killed by it, while others can live with or without it. Be aware that some bacteria produce toxins, which can make you sick but can’t be destroyed, even if the bacteria are gone.
• Molds and Yeast - Molds can be found all over the place and vary greatly in size. The difficult thing about mold is that once it is on your food, it is hard to get rid of. Freezing can stop its growth but won’t destroy it. Some molds also produce toxins.
• Viruses - Viruses live in host cells and can survive both freezing and cooking. The book recommends knowing the source of your food, especially for fish and other seafood.
• Parasites - These pathogens live in/on hosts and can be destroyed by freezing or cooking.

Hazardous Foods

Now that we know what lives on our food, what types of foods are susceptible to them? Three factors contribute to making a food potentially hazardous: moisture, pH, and temperature. And recognize that these aren’t the only types of foods that can have pathogens; different bacteria alone can survive under a huge number of conditions. These criteria merely suggest the most common characteristics of hazardous food.

• Moisture - Moisture is measured on a Water Activity scale of 0 - 1, with 1 being water. Most pathogens prefer food with a moisture content above .85. How do you measure this in foods? I have no idea - just remember moist foods are more likely to grow pathogens.
• pH - Remember that pH is measured on a scale of 0 - 14, with 0 - 7 being acidic and 7-14 being a base (or basic?  Is that the right adjective?). 7 is neutral. Pathogens generally prefer foods in the 4.6 to 7.5 range. Most foods have a pH between those numbers.
• Temperature - This is probably the danger you’ve heard about the most. The danger zone for foods is between 41° and 135° F (5° to 57° C). Keeping foods out of this zone may slow or stop their growth, but it can begin again when the food returns to the right temperature.

Keeping Foods Safe

So how do we keep are foods from becoming a bacteria metropolis? It is a combination of tactics that will keep your food safe. First, wash your hands. I know, it’s obvious, but it is important enough to mention at least. Another obvious one: be aware of expiration dates. With regards to temperature, you could test your refrigerator and freezer temps, which should be between 36° - 40° F (2° - 4° C) and -10° - 0° F (-23° - -18° C) respectively.

From what I can gather, two of the most important parts of controlling food safety is in thawing and cooling foods. This time is when it is most likely that foods will be in the danger zone and grow pathogens. I’ve already covered the right way to thaw foods here, so I’ll run down cooling foods now.

The goal is to have your food cool to below 41° F (5° C) in four hours. A second option is to have the food to 70 F (21 C) in two hours and then 41 F (5 C) in an additional four hours. To achieve this, when cooling liquids, try to use metal containers, as they conduct heat the best. For solids, cut the food into small portions and consider putting it in a thin layer, uncovered to maximize the surface area that will cool. Another option, although one that is significantly more work for the home cook, is using an ice bath. To make an ice bath, just fill a side of your sink with ice and water, and then submerge the bottom of your container of food in the water.

Kitchen Safety

Here are a few final tips on keeping your kitchen safe. First, have a fire extinguisher. For serious.  I started a fire last year in my rental house and a fire extinguisher was very handy. I had spilled some oil around a burner on the stove and it caught fire. Also, in case you start a fire before you run out and buy your extinguisher, remember not to put out a grease or electrical fire with water. Bad things would happen.

Vent covered pots away from your face to prevent steam burns. I got a small steam burn once when I worked at a Skyline Chili in Cincinnati. It was pretty painful. Last, have emergency numbers in your kitchen, just in case. My family always kept them on the inside of a cabinet door.

Hopefully this was helpful and not too boring. Be safe!

Next week: Basic Food Science

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