Bacteria are everywhere - in the air, in the water, in the ground, on our food, on our skin, inside our bodies. Scientists have various ways of classifying and describing these bacteria. As food workers, we are interested in a way of classifying them that may be less scientific but is more practical to our work.
1. Harmless bacteria = Most bacteria fall into this category. They are neither helpful nor harmful to us. We are not concerned with them in food sanitation.
2. Beneficial bacteria = These bacteria are helpful to us. For example, many live in the intestinal tract, where they fight harmful bacteria, aid the digestion of food, and produce certain nutrients. In food production, bacteria make possible the manufacture of many foods, including cheese, yogurt, and sauerkraut.
3. Undesirable bacteria = These are the bacteria that are responsible for food spoilage. They cause souring, putrefying, and decomposition. These bacteria may or may not cause disease, but they offer a built-in safety factor: They announce their presence by means of sour odors, sticky or slimy surfaces, and discoloration. As long as we use common sense and follow the rule that says “when in doubt, throw it out,” we are relatively safe from these bacteria.
We are concerned with these bacteria for two reasons:
• Food spoilage costs money.
• Food spoilage is a sign of improper food handling and storage.
This means the next kind of bacteria is probably present.
4. Disease-causing bacteria, or pathogens = These are the bacteria that cause most food-borne illness, the bacteria we are most concerned with. Pathogens do not necessarily leave detectable odors or tastes in food. In other words, you can’t tell if food is contaminated by smelling, tasting, or looking at it. The only way to protect food against pathogenic bacteria is to use proper hygiene and sanitary food handling and storage techniques.
Each kind of bacterial pathogen causes disease in one of three ways:
1. Intoxications are caused by poisons (toxins) the bacteria produce while they are growing in the food. It is these poisons, not the bacteria themselves, that cause the diseases.
2. Infections are caused by bacteria (or other organisms) that get into the intestinal system and attack the body. Disease is caused by the bacteria as they multiply in the body.
3. Toxin-mediated infections are also caused by bacteria that get into the body and grow. Disease is caused by poisons the bacteria produce as they grow and multiply. Most food-borne diseases are toxin-mediated infections.
[source: professional cooking sixth edition]