Lactic acid-forming bacteria, acetic acid-forming bacteria, and butyric acid-forming bacteria play important roles in food microbiology. Lactic acid-forming bacteria are involved in the production of sauerkraut, cheese, and wine spoilage. Acetic acid-forming bacteria oxidize ethanol to acetic acid and are used to make vinegar and can spoil alcoholic beverages. Butyric acid-forming bacteria, like Clostridium, are spore forming anaerobes.
2. Groups of Bacteria important in Food Bacteriology
Groups of Bacteria Role in Food microbiology
Lactic acid-forming Bacteria
or Lactics
These bacteria ferment sugar to lactose.
Involved in the production of sauerkraut, cheese and spoilage
of wine.
Major genera: Leuconostoc, Lactobacillus, Streptococcus,
Pediococcus.
Acetic acid-forming Bacteria
or Acetics
Oxidize ethanol to acetic acid.
Manufacture of vinegar and spoilage of alcoholic beverages.
Major genera: Acetobacter and Gluconobacter.
Butyric acid-forming Bacteria
or Butyrics
Spore forming anaerobes.
Genus: Clostridium.
Propionic acid-forming Bacteria
or Propionics
Genus: Propionibacterium.
Proteolytic Bacteria Produce extracellular proteinases.
Eg: Bacillus cereus, Pseudomonas fluorescens.
Major genera: Clostridium, Bacillus, Pseudomonas.
Some are acid- proteolytic and cause putrefaction.
3. Groups of Bacteria Role in Food microbiology
Lipolytic Bacteria Produce lipase enzymes that catalyze the hydrolysis of fats to
fatty acids and glycerol.
Major genera: Pseudomonas, Alcaligenes, Staphylococcus,
Serratia and Micrococcus.
Saccharolytic Bacteria Hydrolyze disaccharides or polysaccharides to simple sugars.
Eg: Bacillus subtilis and Clostridium butyricum.
Gas-forming Bacteria Produce small amount of gas and yield it very slowly that is not
ordinarily detected.
Major genera: Leuconostoc, Lactobacillus, Escherichia,
Bacillus.
Osmophilic or
Saccharophilic Bacteria
Grow in high concentration of sugar.
Eg: Species of Leuconostoc.
Pigmented Bacteria Capable of producing pigments.
Serratia- red, Flavibacterium-yellow to orange pigments.
Other groups
Pectinolytic Bacteria
Thermophiles
Psychrophiles
Halophiles
Slime or Rope-forming Bacteria
Coliforms and Fecal Coliforms
4. Importance of Bacteria in Food Microbiology
• Bacteria are important members of Food Microbiology as
they are involved in
• Production of various food and dairy products. Strains of
Streptococcus, Lactobacillus, Bifidobacterium are used in
the production of fermented food and dairy products.
• Pathogenic bacteria cause food intoxications. Example:
C. boltulinum and B. cereus.
• Cause food spoilage. Example: Serratia, Pseudomonas.
5. Reference
• Food Microbiology by Martin R. Adams and Maurice O.
Moss, 3rd e.
• Food Microbiology by William C. Frazier and Dannis C.
Westhoff, 5th e.