Microbial growth and metabolism depends on various factors including. Meat spoilage mechanisms and preservation techniques. Explain fundamental methods of controlling microbial contamination of meat. The influence of environmental factors product composition and storage conditions on the selection, growth rate and metabolic activity of the bacterial flora is presented for meat. Pdf introduction to the microbiological spoilage of foods. Ppt microbial food spoilage powerpoint presentation free. Bacterial spoilage of meat and cured meat products. Specific microorganisms inducing spoilage of cooled. Introduction to the microbiology of food food technology. Nov, 2009 understanding poultry products spoilage approximately 9 billion chickens are processed in the u. The scientific community became interested in meat microbiology when. Meat spoilage meat storage molecular methods the spoilage of raw meat is mainly due to undesired microbial development in meat during storage.
Most common spoilages of microbial origin are known as flat sour spoilage, thermophilic anaerobic ta spoilage and putrefaction. List important pathogens of concern in meat and poultry products. Mar 01, 2011 the microbial spoilage of meat can be classified as aerobic or anaerobic, depending on the conditions under which it occurs and the microorganisms involved. Jun 26, 2018 spoilage is also influenced by temperature not only air but temperature has an important influence on the type of spoilage to be expected in meat. Food spoilage can be defined as any sensory change tactile, visual, olfactory or flavour which the consumer considers to be unacceptable. Meat borne zoonotic diseases such as salmonellosis. The predominant bacteria associated with spoilage of refrigerated beef and pork, are brochothrix thermosphacta, carnobacterium spp. Spoilage is the process of food deterioration leading to a reduction in its quality, to the point of not being edible for humans.
Most meat, vegetable, and dairy products process often at 230of or above retorts, aseptic processing. Poultry meat is spoiled quickly, even under cold storage conditions. Microbial spoilage of foods pdf free download epdf. Microbial spoilage in meat spoilage of meat and poultry is indicated most commonly by development of offodours and offflavours, but can include colour and texture changes, slime or any other undesirable characteristic. To increase the level of wholesomeness all meat and products. Food spoilage may be caused by a variety of mechanisms, including microbial, chemical and physical reactions, and in many cases spoilage can be clearly defined in these distinct terms fig. Introduction to the microbiology of food processing. Lactic acid bacteria chiefly of the genera lactobacillus, leuconostoc, streptococcus, brevibacterium and pediococcus are present in most meats, fresh or cured and can grow even at refrigerator temperatures. Delaying the spoilage of fresh and processed meats iowa state. Show full abstract minimally processed fishery products including fresh meat for retarding microbial growth and enzymatic spoilage. It also includes foodtofood contact, for example between cooked meat and raw meat or between rotting fruit and sound fruit.
Important factors in microbial food spoilage significance of microbial types raw and most processed foods. Foods and microorganisms have long and interesting associations which developed long before the beginning of recorded history. Describe the typical bacterial growth pattern, and explain important factors affecting microbial growth. For example, most meats naturally have a ph of about 5. Food and industrial microbiology food spoilage, food infections and intoxications caused by microorganisms and.
At this ph meat is susceptible to spoilage by bacteria, moulds and yeasts. Sep 11, 2015 factors affecting the spoilage of meat a. Microbial control methods in fresh and processed meats. Microbial food spoilage can define the biological process which involves microorganisms can degrade and decompose the food material, at optimal environmental conditions temperature, ph, oxygen, moisture etc. The microbial volatile organic compounds mvocs are generated in this process as well, and the amount of mvocs can reflect the condition of microbial growth and food spoilage directly wang et al. Ppt microbial food spoilage powerpoint presentation. Spoilage may arise from insect damage, physical damage, indigenous enzyme activity in the animal or plant tissue or by microbial infections. Describe basic mechanisms and indications of microbial food spoilage. Spoilage can occur either during the fermentation period or upon storage of the final product. Microbial growth to large numbers is a prerequisite for meat spoilage that can be considered an ecological phenomenon, encompassing the changes of the available substrata during the proliferation of bacteria 5, 6. Microorganisms may cause healththreatening conditions directly by being ingested together with.
Chilled storage allows psychrotrophic bacteria to grow, for example pseudomonads, but if the surface of fresh meat becomes. It is estimated that 2% to 4% of this meat is lost as a result of poultry spoilage. Introduction to the microbiological spoilage of foods and beverages 3 ta b l e 1 percent loss of the united states food supply from primary production through con sumption abstracted from ers. Microbial deterioration of vacuumpackaged chilled beef cuts. Besides air, temperature has important influences on the spoilage of meat. Describe sources of microbes in meat and poultry products. The term contact spoilage is used when microbial spoilage is the result of direct contact or touching between the food and any contaminated or unclean surface such as shelves, food preparation boards or unwashed hands. Numerous attempts have been made to associate certain metabolites with microbial spoilage nychas and panagou, 2011. The microbial spoilage of meat can be classified as aerobic or anaerobic, depending on the conditions under which it occurs and the microorganisms involved.
Physical signs of spoilage 8 chemical tests of meat 9 water in meat 9 measuring water percentage 10 measuring drip loss 11 ph of meat 12 measuring ph of meat microbial tests 14 microbial tests coliform test 15 salmonella test 17 meat processing laboratory exercises 18 poultry 19 meat preservation 19. Assessment of microbial load of raw meat samples sold in the. Microbial food spoilage involves the following steps. Table 2 shows the microbiological limits for fresh meats that have. Assessment of microbial load of raw meat samples sold in. Although lactic acid microorganisms also can spoil meat, this type of spoilage requires significantly higher numbers of microbes and is less undesirable. Microbiological spoilage of fish and fish products pdf. Declaration i, the undersigned, declare that microbial quality and safety of ostrich meat is my own work and that all sources i have used or quoted have been indicated and acknowledged by means of complete references. This dissertation is brought to you for free and open access by the iowa state university capstones.
A free powerpoint ppt presentation displayed as a flash slide show on id. Fermented and pickled foods owe their stability to the microbial development of organic acids by lactic bacteria or the addition of such acids to the foods, especially in the presence of a relatively high level of salt. Bacteria and yeasts typically result in slime formation, bad odors, rancid flavors, and discoloration grey, brown, or green. Microbiological spoilage of meat and p oultry products. To enhance consumer satisfaction and confidence in meat as a food. Main aspects of the food preservation techniques, alternative food preservation techniques, role of microorganisms in food processing and their positive and negative features are covered. The role played by bacteria in meat spoilage at refrigeration temperatures has been studied since the 1930s jay et al. Microbial food spoilage disorders diseases and its control biochemistry project topics foods and microorganisms have long and interesting associations. In this article we will discuss about the spoilage of different kind of meat. The type of bacteria and their loads depend on the initial meat contamination and on the speci. Laboratory exercises for afghanistan authors paul ebner, phd.
The factors that are considered to have the main effect on the speed of spoilage and the shelf life of fresh meat are intrinsic factors initial number of psychrotrophs present on the meat surface, water activity, the ph value. Microorganisms such as molds, yeasts, and bacteria can grow in food and cause spoilage. The availability of oxygen determines the type of organism that will grow. Microbiological spoilage and contaminatio n of vacuum.
Microbiological spoilage of fish and fish products pdf free. My doctor told me that i am no longer diabetic, that i am free of diabetes and that i can stop all the medications. Lactobacillus sake forms the largest group in radurised well. Microbial contamination and food degradation, volume 10. Food spoilage is the process where a food product becomes unsuitable to ingest by the consumer. Meat spoilage mechanisms and preservation techniques science. Meat spoilage is characterized by the appearance of off odors and slime, which are manifest when surface loads exceed 10 7 cfucm 2. Microbial growth, oxidation and enzymatic autolysis are three basic mechanisms responsible for spoilage of meat. Microbial spoilage of foods spoilage of fresh and readytoeat meat products. The slime is due to the accumulation of bacterial cells. Due to food spoilage, onethird of the worlds food produced for the consumption of humans is lost every year. Lactic acid bacteria chiefly lactobacillus, leuconostoc, streptococcus, and pediococcus are present in either meats and can grow even at refrigerated temperature. Pork is the only meat which spoils more readily than other meats because of its high content of vitamin b. Pdf on jun 1, 2018, asim faraz and others published microbial spoilage of meat.
Microbial spoilage is often due to the growth andor metabolism of spoilage bacteria, yeasts or moulds. Extended refrigeration may have the growth of pseudomonas, acinetobacter, moraxella and causes spoilage of fresh meat. The main defects in meat are offodours and offflavours, but discolouration and gas production also occur. Describe how certain microbes are used in food preservation. Meat and poultry spoilage of meat pdf free download. Many bacteria and molds produce slimes, discolouration, and spots of growth on the surface and may cause souring such as pseudomonas, lactobacillus, alacaligenes, leuconostoc, streptococcus and flavobacterium species.
Spoilage is also influenced by temperature not only air but temperature has an important influence on the type of spoilage to be expected in meat. Apr 22, 2016 features subjects on mechanism of antimicrobial action of heat, thermal process, mechanisms for microbial control by low temperature, mechanism of food preservation, control of microorganisms and mycotoxin formation by reducing water activity, food preservation by additives and biocontrol, food preservation by modified atmosphere, alternative. During bleeding, skinning, and cutting, the main sources of microorganisms are the body parts of the animal and the intestinal tract. Food spoilage microorganisms focuses on the control of microbial spoilage and provides an understanding necessary to do this.
Food spoilage and general principles underlying spoilage of food intrinsic parameters extrinsic parameters microbial spoilage of foods spoilage of fresh and readytoeat meat products spoilage of milk and milk products spoilage of fruits and vegetables spoilage of canned foods major food borne infections intoxications caused by bacteria. Rapid and quantitative detection of the microbial spoilage. The microbial spoilage of canned food is classified as caused by thermophilic bacteria and mesophilic organisms. These are the organisms which cause food spoilage at low moisture, warm environment 560 degrees celsius, neutral acidity and in the presence of oxygen. Interestingly, meat spoilage including poultry and fish occurs without any significant breakdown of the primary protein. The microorganisms most commonly involved in meat spoilage are pseudomonas spp. The initial microbial population on meat depends on the physiological state of the. In spite of decades of effort it has been difficult to obtain food animals free of pathogenic bacteria. Microbiological spoilage and safety risks in nonbeer. This book covers application of food microbiology principles into food preservation and processing. Special forms of spoilage which adversely affect the meat 62. Fresh meat spoilage is considered a surface phenom. In this article we will discuss about the microbial contamination of meats.
Understanding spoilage microbial community and spoilage. Physical signs of spoilage 8 chemical tests of meat 9 water in meat 9 measuring water percentage 10 measuring drip loss 11 ph of meat 12 measuring ph of meat microbial tests 14 microbial tests coliform test 15 salmonella test 17 meat. Nir diffuse reflectance spectroscopy 6001100 nm to quantify the microbial loads in chicken meat and to develop a rapid methodology for monitoring the onset of spoilage. Pdf introduction to the microbiological spoilage of. Microbial contamination and food degradation, volume 10 in the handbook of food bioengineering series, provides an understanding of the most common microbial agents involved in food contamination and spoilage, and highlights the main detection techniques to help pinpoint the cause of contamination. Meat spoilage microorganisms although a range of microbial taxa are found in meat table 1, its spoilage in countries in which meat is stored under refrigeration is caused by relatively few of these organisms table 2. Indications of microbial food spoilage vary with the microbes involved and the time. All these substance can cause microbial growth which can lead to early spoilage. The spoilage of meat occurs, if the meat is untreated, in a matter of hours or days and results in the meat becoming unappetizing, poisonous, or infectious.
Microbial deterioration of vacuumpackaged chilled beef. The important contamination comes from external source during bleeding, handling and processing. Spoilage is caused by the practically unavoidable infection and subsequent decomposition of meat by bacteria and fungi, which are borne by the animal itself, by the people handling the meat, and by their implements. The first part of this essential new book looks at tools, techniques and methods for the detection and analysis of microbial food spoilage with chapters focussing on analytical methods, predictive modelling and stability. Autoxidation of lipids and the production of free radicals are natural processes.
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