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Spoilage of meat

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ketaki patil
ketaki patil

This document discusses microbial spoilage of meat and poultry products. It explains that spoilage occurs when microbes break down food, creating acids and waste products that can make the food unpleasant or harmful. Meat is highly perishable due to its nutrients, pH, and moisture content. Contamination can occur during slaughter or processing and growth depends on temperature, oxygen availability, and other factors. Both aerobic and anaerobic bacteria can cause spoilage through off odors, discoloration, and gas production. Various pathogens are responsible for different types of spoilage in meats like ham, sausage, and canned products. Proper handling and preservation techniques can help delay this natural spoilage process.

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Spoilage of meat
MICROBIAL SPOILAGE OF MEAT AND POULTRY PRODUCTS Presented by:- Ketaki Patil SRM university, Chennai
What is Spoilage??? Spoilage is the process in which food deteriorates to the point in which it is not edible to humans or its quality of edibility becomes reduced.
What is microbial spoilage??? Microbes can be responsible for the spoilage of food. When they breaks down the food, acids and other waste products are created in the process. While the microbes itself may or may not be harmful, the waste products may be unpleasant to taste or may even be harmful to one's health
How it occurs??? Normal slaughtering techniques External sources during bleeding, handling, skinning, cutting and processing. Intestinal tract of animals, exterior of animals ( hide, hooves and hairs) Knives, cloths, air, and hands and clothing of workers. Depends on methods of slaughtering methods such as mechanical, chemical, electrical etc.
MEAT SPOILAGE Raw meat is subject to change by its own enzymes and microbial action and its fat may be oxidized chemically. Autolysis changes include some proteolytic action on muscle and connective tissue and slight hydrolysis of fats. The defect caused by excessive autolysis has been called souring
Invasion of tissue by micro organism Upon the death of the animal, invasion of tissue by contaminating micro organism takes place. Factors influence that invasion includes following:- The load in the gut of the animal The physical condition of the animal immediately before slaughter The method of killing and bleeding The rate of cooling
Growth of micro organism in Meat Meat is an ideal culture for many microbes because it is high in moisture, rich in nitrogenous foods of various degree of complexity , and plentifully supplied with minerals and accessory growth factors. Also, it usually has some fermentable carbohydrate( glycogen) & is at favorable pH for most micro-organism.
Factors influence growth of microorganism The kind & amount of contamination with microorganism and the spread of these microorganism in the meat. The physical properties of the meat Chemical properties of the meat Availability of oxygen Temperature
Types of Spoilage of Meats Spoilage under 1)Aerobic conditions 2)anaerobic conditions
Spoilage under Aerobic conditions Under aerobic conditions bacteria may cause the following- Surface slime which may be caused by species of Pseudomonas, Acinetobacter, Moraxella, Alcaligenes, streptococcus, Leuconostoc, Bacillus, and Micrococcus It is early indication of spoilage, often observed before expiry date.
Changes in color of meat pigment- The red color of meat, called bloom, may be changed to shades of green, brown, gray as result of the production of oxidizing compound . e.g. hydrogen peroxides, hydrogen sulfide. Lactobacillus and Leuconostoc are basically responsible. Changes in fats:- The oxidation of unsaturated fats may takes place chemically in air and may be catalyzed by light and copper. e.g. oxidative rancidity Pseudomonas and Achromobacter are responsible for oxidative rancidity or by yeast.
Phosphorescence This rather uncommon defect caused by phosphorescent or luminous bacteria. E.g. Photobacterium spp. Grows on the surface of meat. Various surface colours due to pigmented bacteria:- red spot may be caused by Serratia marcescens or other bacteria with red pigment. Pseudomonas syncyanea can impart blue color to the surface, Micrococcus or flavobacterium imparts yellow color with yellow pigment and Chromobacterium lividum and other bacteria gives greenish blue or brownish black spot.
Off odors and off taste:- Taints or undesirable odors and tastes, that appear in a meat . souring is the term applied to almost any defect that gives the sour odor that may be due to volatile acids. e.g. formic, butyric,propionic acids Cold storage flavor or taint its nothing but stale flavor. Actinomycetes may be responsible for Musty or earthy flavor
Aerobic growth of moulds may causes Stickiness surface becomes sticky Whiskers- when meat is stored at temperatures near freezing, a limited amount of mycelial growth may takes place without sporulation. Black spot- this usually caused by Cladosporium herbarum White spot- Sporotricum carnis mostly causes white spots.
Green patches- this occurs due to species Penicillum such as p.expansum P.oxalicum Decomposition of fats- many molds have lipase and hence cause hydrolysis of fats .
Spoilage under anaerobic conditions Facultative and anaerobic bacteria can able to grow within the meat under anaerobic conditions and cause spoilage. Following changes occurs in such conditions Souring Putrefacation Taint
Souring it imparts sour taste to meat due to acids such as formic, propionic, acetic etc. meats own enzymes are responsible for it . Putrefaction- true putrefaction is the anaerobic decomposition of protein with the production of foul smelling compound such as hydrogen sulfide, indole, ammonia, amines due to species Clostridium Taint - Taints or undesirable odors and tastes, that appear in a meat
Various spoilage features of Meat Off odor-off flavours Discoloration Gas production
Off odors & off flavours Off odors such as sweet and fruity, putrid, sulphury and cheesy, are characterized in aerobically stored meat. Species which are responsible Psuedomonas sp. & Psuedomonas fragi Sulphur compounds may also contribute off flavor
Discoloration The bacterial production of hydrogen sulphide converts the muscle pigment to green sulphmyoglobin. Hydrogen sulphide is produced from cystein and is triggered by glucose limitation L.sake forms hydrogen sulphide.
Gas production Clostridium spp. have been associated with the production of large amount of gas in vacuum packaged beef , accompanied by foul off-odors. Gas production (co2) by lactic acid bacteria without extensive off odors may be associated with vacuum packaged beef and pork.
organism Responsible for changes Psuedomonas species Off odor and off flavor Microbacterium thermosphactum Spoilage in processed meat Achromobacter species Spoilage in processed meat Lactobacter species Spoilage of vacuum packaged cuts or ground meat Moulds species like Cladosporium Spoilage of beef sides or quarters during prolong storage at 0属c.
Cured meat type Spoilage organism Sliced ham and bacon Souring due to Streptococcus faecium, & Microbacterium thermosphactum Pasteurized canned product Bacillus sps., clostridium sps.,enterococci, streptococci and heat resistance lactic acid bacteria Refrigerated canned product Streptococcus sps.
Type of sausage Type of spoilage Organism responsible Fresh uncooked sausage Putrefaction souring Achromobacter and Psuedomonas & Microbacterium thermosphactum, Cooked sausages Irregular green spots on surface, green cores Narrow green rings within the product Lactobacteriaceae, Leuconostoc, streptococci and pediococci Cooked sausages sliming Yeast , Microbacterium thermosphactum
References Willam C. Frazier Food microbiology Principles Of Meat Technology by V.P Singh Food microbiology by K. Vijaya Ramesh
Spoilage of meat

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Spoilage of meat

  • 2. MICROBIAL SPOILAGE OF MEAT AND POULTRY PRODUCTS Presented by:- Ketaki Patil SRM university, Chennai
  • 3. What is Spoilage??? Spoilage is the process in which food deteriorates to the point in which it is not edible to humans or its quality of edibility becomes reduced.
  • 4. What is microbial spoilage??? Microbes can be responsible for the spoilage of food. When they breaks down the food, acids and other waste products are created in the process. While the microbes itself may or may not be harmful, the waste products may be unpleasant to taste or may even be harmful to one's health
  • 5. How it occurs??? Normal slaughtering techniques External sources during bleeding, handling, skinning, cutting and processing. Intestinal tract of animals, exterior of animals ( hide, hooves and hairs) Knives, cloths, air, and hands and clothing of workers. Depends on methods of slaughtering methods such as mechanical, chemical, electrical etc.
  • 6. MEAT SPOILAGE Raw meat is subject to change by its own enzymes and microbial action and its fat may be oxidized chemically. Autolysis changes include some proteolytic action on muscle and connective tissue and slight hydrolysis of fats. The defect caused by excessive autolysis has been called souring
  • 7. Invasion of tissue by micro organism Upon the death of the animal, invasion of tissue by contaminating micro organism takes place. Factors influence that invasion includes following:- The load in the gut of the animal The physical condition of the animal immediately before slaughter The method of killing and bleeding The rate of cooling
  • 8. Growth of micro organism in Meat Meat is an ideal culture for many microbes because it is high in moisture, rich in nitrogenous foods of various degree of complexity , and plentifully supplied with minerals and accessory growth factors. Also, it usually has some fermentable carbohydrate( glycogen) & is at favorable pH for most micro-organism.
  • 9. Factors influence growth of microorganism The kind & amount of contamination with microorganism and the spread of these microorganism in the meat. The physical properties of the meat Chemical properties of the meat Availability of oxygen Temperature
  • 10. Types of Spoilage of Meats Spoilage under 1)Aerobic conditions 2)anaerobic conditions
  • 11. Spoilage under Aerobic conditions Under aerobic conditions bacteria may cause the following- Surface slime which may be caused by species of Pseudomonas, Acinetobacter, Moraxella, Alcaligenes, streptococcus, Leuconostoc, Bacillus, and Micrococcus It is early indication of spoilage, often observed before expiry date.
  • 12. Changes in color of meat pigment- The red color of meat, called bloom, may be changed to shades of green, brown, gray as result of the production of oxidizing compound . e.g. hydrogen peroxides, hydrogen sulfide. Lactobacillus and Leuconostoc are basically responsible. Changes in fats:- The oxidation of unsaturated fats may takes place chemically in air and may be catalyzed by light and copper. e.g. oxidative rancidity Pseudomonas and Achromobacter are responsible for oxidative rancidity or by yeast.
  • 13. Phosphorescence This rather uncommon defect caused by phosphorescent or luminous bacteria. E.g. Photobacterium spp. Grows on the surface of meat. Various surface colours due to pigmented bacteria:- red spot may be caused by Serratia marcescens or other bacteria with red pigment. Pseudomonas syncyanea can impart blue color to the surface, Micrococcus or flavobacterium imparts yellow color with yellow pigment and Chromobacterium lividum and other bacteria gives greenish blue or brownish black spot.
  • 14. Off odors and off taste:- Taints or undesirable odors and tastes, that appear in a meat . souring is the term applied to almost any defect that gives the sour odor that may be due to volatile acids. e.g. formic, butyric,propionic acids Cold storage flavor or taint its nothing but stale flavor. Actinomycetes may be responsible for Musty or earthy flavor
  • 15. Aerobic growth of moulds may causes Stickiness surface becomes sticky Whiskers- when meat is stored at temperatures near freezing, a limited amount of mycelial growth may takes place without sporulation. Black spot- this usually caused by Cladosporium herbarum White spot- Sporotricum carnis mostly causes white spots.
  • 16. Green patches- this occurs due to species Penicillum such as p.expansum P.oxalicum Decomposition of fats- many molds have lipase and hence cause hydrolysis of fats .
  • 17. Spoilage under anaerobic conditions Facultative and anaerobic bacteria can able to grow within the meat under anaerobic conditions and cause spoilage. Following changes occurs in such conditions Souring Putrefacation Taint
  • 18. Souring it imparts sour taste to meat due to acids such as formic, propionic, acetic etc. meats own enzymes are responsible for it . Putrefaction- true putrefaction is the anaerobic decomposition of protein with the production of foul smelling compound such as hydrogen sulfide, indole, ammonia, amines due to species Clostridium Taint - Taints or undesirable odors and tastes, that appear in a meat
  • 19. Various spoilage features of Meat Off odor-off flavours Discoloration Gas production
  • 20. Off odors & off flavours Off odors such as sweet and fruity, putrid, sulphury and cheesy, are characterized in aerobically stored meat. Species which are responsible Psuedomonas sp. & Psuedomonas fragi Sulphur compounds may also contribute off flavor
  • 21. Discoloration The bacterial production of hydrogen sulphide converts the muscle pigment to green sulphmyoglobin. Hydrogen sulphide is produced from cystein and is triggered by glucose limitation L.sake forms hydrogen sulphide.
  • 22. Gas production Clostridium spp. have been associated with the production of large amount of gas in vacuum packaged beef , accompanied by foul off-odors. Gas production (co2) by lactic acid bacteria without extensive off odors may be associated with vacuum packaged beef and pork.
  • 23. organism Responsible for changes Psuedomonas species Off odor and off flavor Microbacterium thermosphactum Spoilage in processed meat Achromobacter species Spoilage in processed meat Lactobacter species Spoilage of vacuum packaged cuts or ground meat Moulds species like Cladosporium Spoilage of beef sides or quarters during prolong storage at 0属c.
  • 24. Cured meat type Spoilage organism Sliced ham and bacon Souring due to Streptococcus faecium, & Microbacterium thermosphactum Pasteurized canned product Bacillus sps., clostridium sps.,enterococci, streptococci and heat resistance lactic acid bacteria Refrigerated canned product Streptococcus sps.
  • 25. Type of sausage Type of spoilage Organism responsible Fresh uncooked sausage Putrefaction souring Achromobacter and Psuedomonas & Microbacterium thermosphactum, Cooked sausages Irregular green spots on surface, green cores Narrow green rings within the product Lactobacteriaceae, Leuconostoc, streptococci and pediococci Cooked sausages sliming Yeast , Microbacterium thermosphactum
  • 26. References Willam C. Frazier Food microbiology Principles Of Meat Technology by V.P Singh Food microbiology by K. Vijaya Ramesh