meat and meat product spoilage and .pptx

Meat spoilage # diseases due to spoilage

1. Meat and its product are highly nutritious food that is widely consumed by people all over the world. Meat can be obtained from various birds (chicken, turkey, ducks, etc.) or mammals (pork, mutton, buffalo, sheep), and after slaughtering, carcasses and primary cuts are processed to raw or processed food products. It is a nutritious, protein-rich food that is highly perishable and has a short shelf life. The biological and chemical nature of meat leads to its deterioration from the time of slaughter until consumption.  Meat and its products such as ham, sausages, cooked meat, dry meats, smoked meats, vacuum-packed meat, minced meat, etc. are all susceptible to  microbial spoilage . Microbial spoilage of meat and meat products Introduction

2. Contamination source and causes C aused by natural processes, like lipid oxidation or autolytic enzymatic that occurs in the muscle after slaughtering.  Several factors are responsible for microbial contamination of meat such as: Bacterial flora of animal. Knives, utensils, hands, and clothing of the workers. Pre-slaughter handling of livestock and post-slaughter handling of meat. handling during slaughtering, evisceration, and processing temperature controls during slaughtering, processing and distribution type of packaging used Handling and storage 

3. RIGOR MORTIS (events following it ) Respiration ceases , which stops ATP synthesis. lack of ATP causes stiffening of muscle Reduction of oxidation-reduction potential due to lack of oxygen The loss of vitamins and antioxidants causes the development of rancidity. Glycolysis begins in which most glycogen is converted to lactic acid that reduces pH. The ending of a reticuloendothelial system leads to the susceptibility of meat to microorganisms. Nervous system cease , thereby causing the temperature of the animal to fall and fat to solidify. Various metabolites accumulate that also aid protein denaturation.

4. Spoilage of fresh meat Fresh meat is subjected to spoilage by enzymes microbial action. AUTOLYSIS - cause proteolytic action on muscle and connective tissue and hydrolysis of fats. Fresh meat contains nutrients - sugars, amino acids, vitamins, cofactors, etc and it had pH (5.5-5.9) and Aw (0.85). B acteria - cinetobacter , Pseudomonas, Brochothrix thermosphacta , Flavobacterium, Psychrobacter , Moraxella, Staphylococci, Micrococci, lactic acid bacteria (LAB). Pathogens-   Salmonella, Campylobacter, E.coli, Listeria monocytogenes. There are two types of spoilage of meat: Spoilage under Aerobic condition Spoilage under Anaerobic condition

5. The kind of defects caused by microorganisms on fresh meat Condition Kind of defects Microorganisms Aerobic condition Surface slime Pseudomonas, Moraxella, Streptococcus, Bacillus, micrococcus  The red color of meat called “bloom” caused by the production of an oxidizing compound Lactobacillus, Leuconostoc Oxidative rancidity Pseudomanas spp, Archromobacter Red spot Serratia marcescens,  Blue color Pseudomonas syncyanea Greenish blue or brownish black spot Chromobacterium lividum Stickiness, whiskers, Green patches Mold Anaerobic condition Putrefaction Clostridium  spp, Alcaligennes, Proteus Souring Lactic acid bacteria

6. Spoilage of meat 3 BASIC MECHANISMS - Microbial growth, oxidation, and enzymatic autolysis responsible for the spoilage of meat. E xcellent medium for microbial growth – N utrient composition, H igh water content, M oderate pH of meat. Flora of animal’s lymph nodes contaminating meat -   Staphylococcus, Streptococcus, Clostridium, and Salmonella. Bacteria -Acinetobacter, Aeromonas, Alcaligenes, Alteromonas , Brochothrix , Carnobacterium , Escherichia, Enterobacter, Enterococcus, Flavobacterium, Lactobacillus, Leuconostoc , Micrococcus, Proteus, Pseudomonas, Sarcina , Serratia,  and  Streptococcus . Pathogens - Salmonella enteric strains, Yersinia enterocolitica, Campylobacter jejuni , Aeromonas hydrophila , Listeria monocytogenes,  and  Escherichia coli .  Mold -  Cladosporium, Sporotrichum , Geotrichum , Penicillium,  and  Mucor   yeasts - Candida spp., Cryptococcus spp ., and  Rhodotorula spp . Main defects -off-odour, off-flavour, discoloration, and gas production.

7. Some defects caused by microorganism in different kinds of meat are: Products Defects Microorganisms Vacuum packed meat Sulfide odor Clostridium spp., Hafnia spp. H2S greening Shewanella spp. Blown Pack Clostridium spp., lactic acid bacteria Fresh meat Putrefaction Alcaligenes, Clostridium, Chromobacterium, Proteus vulgaris, Pseudomonas fluorescens Souring Chromobacterium, Pseudomonas Cured meat Moldy odor Aspergillus, Penicillium, Rhizopus Greening Pediococcus, Streptococcus Souring Micrococcus, Pseudomonas Slimy  Leuconostoc Modified atmosphere packaging meats Souring, off-odor  Leuconostoc, Lactobacillus Souring B. thermosphacta Refrigerated packaged meat Off-flavors, slime, putrefaction Pseudomonas, Acinetobacter, Moraxella sour, slime, and flavor change Lactic acid bacteria

8. Spoilage of refrigerated meat When fresh meat is refrigerated at 4 ± 1°C, they remain in good condition for 5-7 days which favours the growth of psychrophilic organisms in due course of time. C ontaminations occur during slicing and serving operations, from hands, slicing machines. BACTERIA- of refrigerated meat - Acinetobacter, Moraxella, Pseudomonas, Aeromonas, Alcaligenes , and  Micrococcus. MOLDS - Alternaria, Cladosporium, Geotrichum , Mucor, Monilia, Penicillium, Sporotrichum , and Thamnidium ; YEAST - associated with spoilage of refrigerated meat are  Candida, Torulopsis , Debaryomyces ,  and  Rhodotorula . PATHOGENS - C botulinum type E, Yersinia enterocolitica, E nteropathogenic Escherichia coli, Listeria monocytogenes, Aeromonas hydrophila  as they are capable of growing at temperatures below 5°C.

9. Spoilage of cured meat Cured meat - preserved by aging, drying, canning, brining, or smoking for enhancement of flavor shelf life. EXAMPLES - sausage, bacon, salami, ham, canned meat, dry spicy meat, meat pickles, kebab, meatballs, meat patty, etc. The cured meat has a long shelf-life compared to fresh and raw meat But unimmune to spoilage. The bacterial spoilage causing organisms in processed and cured meats are lactic acid bacteria EXAMPLES-  Lactobacillus sake Lactobacillus curvatus , Leuconostoc gelidium , Leuconostoc carnosum , Leuconostoc mesenteroides ,   Acinetobacter, Bacillus, Micrococcus, Serratia,  and  Staphylococcus . M old in cured meat - Aspergillus, Penicillium, Rhizopus,  and   Thamnidium Y east in cured meat - Candida, Debaryomyces ,

10. Torula, Torulopsis ,  and  Trichosporon . Other spoilage microorganisms- Clostridium  spp , Hafnia  spp , Weisella   spp , Shewanella   spp , Pseudomonas  spp , Enterococcus  spp , etc.  Pathogens -   Escherichia coli, Salmonella, Staphylococcus aureus, Listeria monocytogenes, Clostridium botulinum,  and  Toxoplasma gondii.

11. Spoilage of Poultry and Poultry Products Poultry meat is the muscle tissue of chicken, ducks, turkey etc. The reference to poultry meat generally is the dressed chicken’, similarly considered along with the other meats. The spoilage organisms involved also follow more or less the same pattern. Post processing, like evisceration (removal of the parts), the meat is stored under chill conditions. Under this storage temperature, the bacterial growth in poultry meat takes place on the surface. Once the spoilage takes place, off- odours are initially noticed and then followed by slime formation. Species belonging to Pseudomonas - primary spoilage organisms in the meat held at 10°C or less. Above 10°C, Micrococci, Alcaligenes and Flavobacterium also grow.Next , let us look at the spoilage of poultry products, specifically eggs.EggsMost of the freshly laid eggs are sterile, although it may get contaminated through cracks in the shell.

12. Washing aids in the spoilage of eggs due to increased moisture on the surface of the shell. The bacteria which cause spoilage of eggs include species of Pseudomonas, Micrococcus, Bacillus, Proteus, Alcaligenes, Flavobacterium and Salmonella. Moulds found on eggs include Penicillium, Aspergillus, Cladosporium, Mucor and Rhizopus. But the spoilage is generally caused by bacteria than mould . Once the bacteria invade the inside of an egg, they develop characteristic odours and appearance. The common form of spoilage is known as rotting. CANDLING - How do we know whether an egg is rotten? Whether an egg is defective or not, could be identified by subjecting the egg to 'candling', which is a technique which involves rotating the egg in front of the candle light . This helps in identifying the cracks, rots etc. There are different types of rots characteristic to egg spoilage , for example- Black rots: The black rots are caused by bacterial species of Proteus, Aeromonas and Pseudomonas. The species of Proteus usually causes the black rot. The egg under this condition, when broken, gives a muddy dark brown appearance with putrid odour due to hydrogen sulphide .

13. Red rots: This rot is caused by Serratia marcescens and is distinguished by a red colour . Pink rots: This is caused by the species of Pseudomonas. Green rots: Pseudomonas fluorescens is the causative organism of this rot, which fluorescens under the UV light. Colourless rots : Acinetobacter, Alcaligenes and Pseudomonas are responsible for this rot. Of all the rots, the important ones are the green, colourless and black rots. Pink rots are not frequently encountered