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Fermented Meat By Akrum Hamdy. Contents 1. Introduction a) Nutritional role of meat in the human diet b) The relationship between meat in the diet and disease 2. The history and culture related to fermented meat 3. The fermentation process
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Fermented Meat By Akrum Hamdy
Contents 1. Introduction a) Nutritional role of meat in the human diet b) The relationship between meat in the diet and disease 2. The history and culture related to fermented meat 3. The fermentation process a) Fermentation of a comminuted meat matrix i) Variables in sausages production ii) Sausages as possible probiotics b) Fermentation of whole meat products (Ham) 4. Composition and changes during fermentation a) Fermentation Microflora b) Acidification, Dehydration, and Microbial Antagonism c) Proteolytic and Lipolytic degradation during fermentation d) Generation of flavor volatiles e) Biogenic Amines 5. Potential Beneficial health effects of Bacteria involved in meat 6. Conclusions 7. References
1.Introduction Meat is the flesh (muscle tissue ) of warm-blooded animals, but fermented specialties from poultry ( sausages as well as cured and smoked fermented poultry) are available. What is fermented sausage? A sausage is fermented if -its pH below 5.6 and D-lactic acid content above 0.2% -its colour is heat-stable -its texture is no longer crumble -its aroma is typical -lactic acid bacteria predominate -Enterobacteriaceae counts are low
Table. 1Meat consumption in the 1980s and 1990s (g per person per day) Country 1980s 1990s United states 310 231Australia 296 290United Kingdom 201 204 France 290 305 Germany 269 261 Japan 100 123 China 25 108Source: The values quoted are from the Organization for Economic Development and Cooperation (OECD) for the years 1982-1984 and 1992, respectively. The exception is China; these values are taken from Asia Pacific Food Industry 7, 14, 1995, using the years 1979 and 1994. The figures include bone weight.
a) Nutritional Role of Meat in the Human Diet: • essential component of the human diet to ensure optimal growth and development. • as a concentrated source of a wide range of nutrients. • high digestibility required relatively smaller guts. • meat and meat products has increased with the affluence of the consumer. • fat content of meat as consumed is around 2to5%. • protein of high biological value. • micronutrient such as iron, zinc, vitamin B1, niacin equivalents, and vitamin B12 significantly contribute to the nutritional value of meat. • red meat contains 50-60% of iron in the hame from (from hemoglobin and myoglobin).
Classification of Whole Meat Products 1) Classical Ham- Made from thigh of hog with or without bone 2) Cuts of Meat-Pork 3) Other Animal Sources- beef 4) Mutton
b)The relationship between Meat in the diet and Disease • strong correlation between consumption of meat and the incidence of colon cancer among various countries. • consumption of red meat was associated with a high risk of colon cancer. • energy intake was positively associated with a higher risk of colon cancer. • intake of fat, protein, and carbohydrates were not related to cancer risk. • intake of cholesterol was higher (560 to 710mg/day) compared lower (∠20mg/day) is elevated serum cholesterol levels • the Japanese diet has been associated with low incidence of large bowel cancer. -Regular consumption of meat is associated with increased risk of death from coronary heart disease (CHD). • higher intake of red meat may be involved in cardiovascular disease
2. The history and culture related to fermented meat. • Meat is extremely susceptible to microbial spoilage. • meat as a substrate are optimal for the growth of bacteria. • water activity and pH are 0.96 to 0.97 and 5.6 to 5.8, respectively • nutrients and growth factors are abundantly available. • storage and preservation of meat is necessary for the suppression of microbial growth or the elimination of microorganisms and prevention of recontamination. • The traditional methods which comprise reduction - 1) water activity ( drying, salting) and/ or pH (fermentation, acidification) 2) smoking, storage at refrigeration or freezing temperatures, 3) use of curing aids (nitrite and nitrate) • meat may also contain bacterial food pathogens. • meat has to be of high quality with regard to hygiene and microbial counts.
3. The fermentation process Fermentation process : two types -foods from a comminuted matrix -whole meat products.
A. Fermentation of a Comminuted meat matrix a) Variables in sausage production Variables include: • The particle size of the comminuted meat and fatty tissue (1 and 30 mm) • The selection of additives (curing salt, nitrate, ascorbic acid, sodium glutamate and glucono-∂-lactone -source glucose. • The temperature /humidity (below 2to 3℃, the temperature is raised usually to ＞20℃ and ＞28℃, but maximum higher temperatures (32 to 38℃). • The diameter of the sausages • The nature of the casings smoking • Heating after fermentation • Supporting the development of mold growth on the surface or establishing a special tight surface film (e. g. coating with a titanium dioxide film) • Dipping in antifungal preparations ( sorbic acid or pimaricin) • pH-4.8 to 5.4
Species Employed in Meat Starter Cultures • Bacteria: Lactic Acid Bacteria such as Lactobacillus acidophilus, Lb. alimentarius, Lb. curvatus, Lb. plantarum etc, Lactococcus lactis, Pediococcus acidilactici, P. pentosaceus • Actinobacteria : Kocuria varians, Streptomyces griseus, Bifidobacterium spp. • Staphylococci: Staphylococcus xylosus, S. carnosus ssp. • Halomonadaceae : Halomonas elongata • Fungi: Penicillium nalgiovense, P. chrysogenum, P. camemberti • Yeasts: Debaryomyces hansenii, Candida famata
b) Sausages as Possible Probiotics • contain the probiotic bacterial strain which effective in the intestines. • probiotic bacteria supports survival and metabolic activity in the intestinal tract. • probiotic food should have been performed to substantiate any health claim • lactobacilli and bifidobacteria (probiotic strains) had been used for sausage production • Lactobacillus paracasei are used for the production of moist type of fermented sausage • large reduction of pH-∠5.0 • extended ripening―＞1 month • drying, or excessive heating • in these condition all strains of bacteria damaged or killed.
B. Fermentation of Whole Meat Products (HAM) • curing by salting (with or without the use of nitrite and/or nitrate) • to achieve a water activity of ∠0.96 (equivalent to 4.5% sodium chloride) • temperatures (50C)―the salt will diffuse to the deepest part of meat • overcoming the food poisoning through Clostridium botulinum contamination. • after equilibrating the salt concentration and flavor development, the temperature is raised to 15 to 250C to ripen the ham. • optimum flavor has no changed at least 6 to 9 months, maximum 18th month. • at the end of ripening step, the moisture has been reduced by 25% and salt 4.5 to 6%)
4. Composition and changes during fermentation • growth of LAB and concomitant acidification of the product. • reduction of nitrates to nitrites and formation of nitrosomyoglobin • solubilization and gelification of miofibrillar and sarcoplasmic proteins • degradation of proteins and lipids • dehydration
a) Fermentation Microflora • sausage minces favor the growth of Micrococcacea and Lactobacilli (5×108 to 109 CFU/g) • Micrococcacea such as Kocuria varians, Staphylococcus carnosus or S. xylosus grow to cell counts 106 to 107 CFU/g, when nitrate cure is applied. • inhibited the growth of organism • the predominant microorganism is isolated • growth of Staphylococcus occurs • Penicillium constituted 96% of the microflora • the nontoxigenic species Penicillium nalgiovense was most frequently isolated • the halotolerant yeast (Debaryomyces hansenii) is the predominant
b) Acidification, Dehydration, and Microbial Antagonism • isoelectric point of meat proteins (pH 5.3 to 5.4) • increase the ionic strength • sodium chloride and lactate in fermented sausages develop taste of the product. • acidification and drying are importance for inhibition of the growth of pathogens. • low pH and water activity exert an inhibitory effect towards pathogens. • lactic and acetic acids are the major fermentation products • the dry matter content 50-75% • the water activity values .86-.92 depend on ripening
c) Proteolytic and Lipolytic Degradation during fermentation • Peptides and amino acids accumulate to levels of about 1% dry matter • Peptides and amino acids act as flavor enhancers and synergists. • excess proteolysis may result in bitter and metabolic off-flavor • amino acids and peptides are utilized by microorganisms for the conversion to flavor volatiles • the bioactive peptides is influenced by lactic fermentation • Kocuria varians is inhibited by environmental conditions • Lb. casei utilizes peptides released from pork muscles • fat content 40-60% of dry matter • long chain fatty acids are released from triglycerides and phospholipids • free fatty acids are found 5% of the total fatty acids. • polyunsaturated fatty acids is higher than saturated fatty acids.
d) Generation of Flavor volatiles Routes: • by lipolysis and hydrolysis of phospholipids, followed by oxidation of free fatty acids. • microorganisms produce organic acids: convert amino acids and peptides to flavor-active alcohols, aldehydes, and acids • modify products of lipid oxidation • aroma is determined by the addition of spices, smoking, or surface-ripening with yeasts or molds.
Table. 4 Mechanisms for generation of flavor compounds
e) Biogenic amines • histamine, tyramine, phenylethylamine, tryptamine, putrescine and cadaverine not exceeding 100mg/kg. • are mainly derived from bacterial decarboxylation of amino acids • putrescine and cadaverine are produced by the Gram-negative spoilage flora • starter cultures inhibit rapidly metabolism of Gram negative bacteria • effectively reduce tyramine levels in fermented sausages
5. Potential beneficial health effects of bacteria involved in meat fermentation • LAB act as a human intestinal microflora and man-made ecosystems • microorganisms may contribute to the microbial ecosystem of the gastrointestinal tract • bacteria survive gastrointestinal transit • LAB have been predicted with the use of in vitro experiments • some bacteria have capability to survive low pH (1.5-2.5) and bile (10mM ) • to attach to enterocyte-like CaCO-2 cells
5. Potential beneficial health effects of bacteria involved in meat fermentation • had been rendered free of lactobacilli by antibiotic treatment • to participate in the initiation and regulation of the mucosal immune response • responsible for antigen presentation-cytokine and cytokine receptors • intestinal microflora may directly encounter cells of the specific and nonspecific immune system • lactobacilli are potent inducers of monocyte derived cytokine IL-12 • Lactobacillus and Bifidobacterium were effective in reducing mucosal inflammation • maintenance of remission in patients with chronic pouchitis
Product Diversity and Sensory Properties • The main desirable effects of starter micro-organisms on flavor and taste of fermented meats are • formation of lactic acid • transformation of compounds from abiotic breakdown of lipids • degradation of peptides and amino acids formed by meat proteases • Indirect effects are • consumption of oxygen • reduction of nitrate • protein degradation by mould proteases
6. Conclusions • LAB as a part of traditional human diet or probiotic therapy • influence the homeostasis between the intestinal microflora and the host • prevention and treatment of certain disease • use as a multitude of bacterial species in various food matrices • to select bacterial strains that are capable of producing a fermented meat product • provide beneficial probiotic effects
References Campbell-Plant, G. and Cook, P.E., Eds. Fermented meats, Blackie Academic & Professional, Glasgow, 1995 Lucke, F.K., Fermented sausages, in Microbiology of Fermented Foods, Vol.2.,2nd ed., Wood, B.J.B., Ed., Blackie Academic & Professional, Glasgow, 1998, pp-441-483 Hambraeus, L., Animal and plant-food-based diets and iron status: benefits and costs, proc. Nutr. Soc., 58, 235-242, 1999 Phillips, R.L., Kuzma, J.W., Beeson, W.L., and Lotz, T., Influence of selection versus lifestyle on risk of fatal cancer and cardiovascular disease among Seventh-day Adventists, Am. J. Epidemiol., 112, 296-314, 1980. Mann, N., Dietary lean red meat and human evolution, Eur. J. Nutr., 39, 71-79, 2000. Kritchevsky, D., Tepper, S.A., and Goodman, G., Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Relationship of diet to serum lipids, Am. j. Clin. Nutr., 40, S921-S926, 1984 Armstrong, B. and Doll, R., Environmental factors and cancer incidence mortality in different countries, with special reference to dietary practices, Int. J. cancer, 15, 617-631, 1975.
