Food microbiology  



  Food microbiology is the study of the microorganisms which inhabit, create or contaminate food. Of major importance is the study of microorganisms causing food spoilage. However "good" bacteria such as probiotics are becoming increasingly important in food science. In addition, microorganisms are essential for the production of foods such as cheese, yoghurt, other fermented foods, bread, beer and wine.

  Food safety is a major focus of food microbiology. Pathogenic bacteria, viruses and toxins produced by microorganisms are all possible contaminants of food. However, microorganisms and their products can also be used to combat these pathogenic microbes. Probiotic bacteria, including those which produce bacteriocins can kill and inhibit pathogens. Alternatively, purified bacteriocins such as nisin can be added directly to food products. Finally, bacteriophage, viruses which only infect bacteria, can be used to kill bacterial pathogens. Thorough preparation of food, including proper cooking will eliminate most bacteria and viruses. However, toxins produced by contaminants may not be heat-labile, and some will not be eliminated by cooking.

  Fermentation is one way microorganisms can change a food. Yeast, especially S. cerevisiae, is used to leaven bread, brew beer and make wine. Certain bacteria, including lactic acid bacteria, are used to make yogurt, cheese, hot sauce, pickles.



     Foodborne pathogens   
pathogens are the leading causes of illness      and death
     Protozoan parasites associated with food and water can      cause illness in humans
    Molds produce mycotoxins, which are secondary metabolites      that can cause acute or chronic diseases in humans when      ingested from contaminated foods.
 Vibrio species are prevalent in marine environments
  Staphylococcus aureus
Staphylococcus aureus is a common cause of bacterial     foodborne disease worldwide.    
infections are commonly acquired by animal to human
Shigella species are members of the family     Enterobacteriaceae and are Gram negative
Escherichia coli
E. coli was considered a commensal of human and      animal intestinal tracts with low virulence potential.     Clostridiumbotulinum and Clostridium perfringens
Clostridium botulinum produces extremely potent     neurotoxins that result in the severe neuroparalytic disease,     botulism.
Bacillus cereus

    B. cereus is a normal soil inhabitant and is frequently     isolated from a variety of foods, including vegetables,     dairy products and meat.
Water activity
 Water activity or aw is a measurement of the energy     status of the water in a system.   
  Pasteurization is the process of heating liquids for the     purpose of destroying bacteria, protozoa, molds, and     yeasts.
 Sterilization refers to any process that effectively kills or     eliminates transmissible agents