Important Bacterial Groups in Foods PDF

Dept. of Agricultural Microbiology S H I M AA AB D E L R AO U F AM I N AS S O C I AT E P R O F E S S O R O F AG R I C U LT U R E M I C R O B I O L O G Y FAC. O F AG R I. , AI N S H AM S U N I V E...

Dept. of Agricultural Microbiology S H I M AA AB D E L R AO U F AM I N AS S O C I AT E P R O F E S S O R O F AG R I C U LT U R E M I C R O B I O L O G Y FAC. O F AG R I. , AI N S H AM S U N I V E R S I T Y  Important Bacterial Groups in Foods Among the microorganisms found in foods, bacteria constitute major important groups. This is not only because many different species can be present in foods, but also because of their rapid growth rate, ability to utilize food nutrients, and ability to grow under a wide range of temperatures, aerobiosis, pH, and water activity, as well as to better survive adverse situations, such as survival of spores at high temperature. Bacteria important in foods have been divided into several groups. Some of these groups and their importance in foods are listed here. 1) Proteolytic Bacteria They are bacteria that can hydrolyze proteins because they produce extracellular proteinases. Species in genera Micrococcus, Staphylococcus, Bacillus, Clostridium, Pseudomonas, Alteromonas, Flavobacterium, Alcaligenes, some in Enterobacteriaceae,and Brevibacterium are included in this group. 2) Lipolytic Bacteria They are bacteria that are able to hydrolyze triglycerides because they produce extracellular lipases. Species in genera Micrococcus, Staphylococcus, Pseudomonas, Alteromonas, and Flavobacterium are included in this group. 3) Saccharolytic Bacteria They are bacteria that are able to hydrolyze complex carbohydrates. Species in genera Bacillus, Clostridium, Aeromonas, Pseudomonas, and Enterobacter are included in this group. 4) Halotolerant Bacteria They are bacteria that are able to survive high salt concentrations. Some species from Bacillus, Micrococcus, Staphylococcus, Pediococcus, Vibrio, and Corynebacterium are included in this group. 5) Aciduric Bacteria They are bacteria that are able to survive at low pH (