Cooking safely

Cooking food at in the temperature range of 175200F (8095C) has some disadvantages that you should be aware of.

1. Large meat cuts
The danger zone (40 -140º F or 5 - 60°C) is the temperature range that food bacteria can grow. These bacteria have the potential to cause food poisoning.

Large cuts of meat like pot roasts or whole chickens heat up slowly in a slow cooker and can allow food poisoning bacteria to multiply to substantial numbers while the food is in the danger zone. Bacteria such as Staphylococcus aureus and some strains of E. coli produce toxins which are heat stable at normal cooking temperatures, even though food bacteria are all destroyed at 165°F - 75°C. These toxins can make the people very sick when they eat the food.

The risk of food poisoning can be minimised by browning the roast or searing the meat in a hot skillet or pan. This kills most of the surface bacteria where the majority of the bacteria are. Be careful not to cross contaminate! That is, do not place the cooked meat onto a surface that contains the raw juices and the bacteria of the uncooked meat. An additional benefit of searing the meat is it produces browning reactions in the cooking process which help develop the full intense flavor of cooked meat.

Stainless steel prongs can also be placed into the seared meat cut. Metal is a good conductor of heat and this will heat up the inside of the meat cut much faster.

The meat can also be cut into smaller pieces to ensure thorough cooking. This also shortens the time the food will remain in the danger zone.

2. Toxins from raw and under cooked beans.
Raw or undercooked beans, especially red and white kidney beans, contain the toxin phytohaemagglutinin which is destroyed by boiling at 232°F / 100°C. Heating kidney beans to 175°F/ 80°C can increase the level of poison up to five fold as more of the toxin is released. Red kidney beans also contains about three times more toxin than white kidney beans.

The toxin, phytohaemagglutinin, causes red blood cells to clump together. Symptoms of bean poisoning include extreme nausea, some patients developing abdominal pain. Severe vomiting may follow and after several hours diarrhoea develops. Sometimes hospitalisation may be necessary.

Recipes on this site which contain kidney beans use canned beans which have been previously heated and are safe.

If other types of raw beans are used they must not be sprouted. All dry beans must be soaked overnight. Discard the soaking water, replace with fresh water and boil for 15 minutes.

3. Loss of Vitamins

Biological enzymes contained in foods, particularly vegetables brake down vitamins. When vegetables are boiled at 232°F / 100°C the enzymes are quickly denatured, like egg whites curdling when cooked in water.

The slow cooker process doesn’t boil the food so the enzymes reduce the vitamin content during the cooking process. This can be prevented by blanching the vegetables before they are placed into the slow cooker. Sauteing the food also destroys the enzymes and helps preserve vitamins.