Meat Fermentation Presentation

•Geography dictates the types of fermented meet products.
•In warmer areas, the Middle East and around the Mediterranean, spices were often added, and a drying step was common.
•In colder, Northern areas, where sausage technology is more recent, spices were rarely added, and instead products were usually smoked or sometimes cooked following fermentation.
•the preservation of fermented meats serves as a perfect example of what food scientists now refer to as the hurdle or barrier concept of food preservation.
•Today the variety of fermented meat products ~ cheese in the world.
•In Spain : 50 different types of fermented sausages
•in Germany: more than 350.
•this variation is due to
-the meat source (i.e., beef, pork, goat, sheep, etc.)
-the cut of meat
-the amount and coarseness of the fat
-the casing material used
•The level of dryness, smoking or mold growth are important factors and form the basis of fermented meats classification
• Meat Composition
•Fresh meat is a nutrient-rich medium and is, in fact, one of the best for supporting growth of microorganisms.
•Skeletal bovine muscle contains:
•- 20% of high quality protein
•- 2% to 3% lipid
•-small amount of carbohydrate
•-non-protein nitrogen and inorganic material.
•-about 75% is water( aw is nearly 0.99)
•-pH of the fresh tissue, before rigor, is 6.8 to 7.0, but decreases to about 5.6 to 5.8 following rigor, due to post-mortem glycolysis by endogenous enzymes present within muscle cells.
• Fermentation Principles
•the meat fermentation has been, until recently, considerably less well studied and understood.
•the use of pure, defined starter cultures begun in the 1950s and ‘60s. Before backslopping were common.
•Backslopping works for several reasons:
•-selects bacteria that are well suited for growth in the sausage environment.
•-the bacterial population is heterogenous consisting of multiple species and strains. (If one strain were to suddenly die remaining strains could complete the fermentation.)
•-effective due to large size of the inoculum (usually around 5%, can be as high as 20% of the total mass to overwhelm the background flora)
•drawbacks of backslopping:
•-inconsistent quality
•-fermentations can be unreliable and difficult to control.
•-can’t meet tight production schedules
•-microbiologically risky, may permit growth of Staphylococcus aureus, Listeria monocytogenes, C. botulinum, or other pathogens of public health significance
•If a cooking step is not included, fermentation is the main barrier against pathogens.
•a slow or failed fermentation may not be discovered right away permitting growth of pathogenic bacteria.
•subsequent acid production (or even a heating step) may not be sufficient to inactivate these high level of pathogens.
Sausages grouped under four major category
• -Fermented sausages or sausages dried in air
•( can be consumed without cooking, normal sausages) Ham ( from pork )—- equivalently pastırma ……prepared from uncooked materials
•-Boiled sausages …..prepared from uncooked materials but during processing either boiled in water or treated with steam …frankfurter, salami ( in Turkish sosis, salam..)
•-cooked sausages
•-fried sausages
•Semidry sausages (in USA) : rapid fermentation at an elevated temp, without or with a short period of drying followed by cooking (at 60–68°C).

Traditional Mediterranean:slow ripening process, development of moulds and yeasts on the surface. No smoking. Shelf-life: due to drying and reduced aw .
In northern and central Europe, fermentation+smoking, of yeasts and moulds are prevented, and the drying is shorter.
summer sausage, fermented at 38 °C and no drying.
Microbiology of Fermentation
• meat is naturally contaminated with Lactobacillus, Carnobacterium, Micrococcus, Staphylococcus, Pseudomonas, Acinetobacter, Enterococcus, Arthrobacter, Corynebacterium, Brochothrix and Listeria, and also Enterobacteriaceae, yeasts and moulds.
•Spoilage Bacteria
•Gram-negative aerobic spoilage mos, disappear through the fermentation period.
•Pathogenic Bacteria
Clostridium, Staphylococcus aureus, Listeria and Enterobacteriaceae (including Salmonella):easily controlled if good practice is applied.
Starter Cultures for Fermented Sausages
•The LAB : Lactobacillus sakei, L.curvatus, (18-25C)(slow fermentation to provide sufficient time for nitrate-reduction and color and flavor development )L. plantarum,
Pediococcus acidilactici and P. pentosaceus. ( 35-40 C)
( for fast, consistent large scale productions)
•Yeasts (Debaryomyces hansenii, Candida famata) and moulds (Penicillium nalviogense, P. chrysogenum or P. camemberti) are added to the surface of the casing.
• acetic acid:undesirable in fermented sausage because it imparts a sour, vinegar-like flavor
•the inclusion of Micrococcaceae (mesophilic : 18°C to 25°C) in meat starter cultures is optional.( don’t produce acid to convert nitrate to nitrite by enzyme nitrate reductase in turn ( they form flavor and enhance color )
•If ferment at higher temp (e.g., 32°C to 40°C), the rapid acid development would inhibit growth of the micrococci
functions of meat starter cultures
(1) produce L acid and lower the pH;
(2) produce desirable flavors;
(3) out-compete spoilage and pathogenic mos;
(4) lower the Eh, ( inhibits Salmonella, S. Aureus);
(5) Micrococcaceae :flavor and color via reduction of nitrate.
•Bacteriocins: proteinaceous substances with bactericidal activity.Produced by: P. acidilactici, L. plantarum, and L. sakei.
•Bacteriocins provides one more barrier and an extra margin of safety.
•- nisin: only bacteriocin recognized GRAS
How to include bacteriocin?
•- adding bacteriocin-producing strains in a starter culture
•-a pure bacteriocin : added directly to the sausage batter or applied to the surface in the form of a dip or spray.
•- incorporate bacteriocins into packaging films.
Raw Materials and Additives
•only five ingredients are essential:
•meat, sugar, salt, culture, and a curing agent.
•Meat the main ingredient. Beef fat ( more unsaturated lipids) than pork fat ( susceptible to oxidation rxns, rancid flavors) pH should be 5.8 or lower to prevent undesired bacteria)
•Salt ( essential ingredient in all types)
•Functions: -extracting and solubilizing the muscle proteins
•-provides flavor, -controlling the microflora.
(2–4%) containing 0.4–0.6% sodium nitrite (NaNO2)
Sugar
•fresh meat contains little fermentable sugar, and addition of sugar is necessary.
•glucose (0.5–1%) can be added to impart flavour and moderate the harshness of salt
•Addition of reducing sugars (e.g. glucose solids, dextrose) to the brine: helps in browning reactions (bacon.)
•Ascorbates/Erythorbates(isoascorbic acid)
•sodium ascorbate or ascorbic acid (0.5–1%) ( to prevent oxidation, improve color stability)
•helps in the prod. of nitric oxide (NO) from nitrite
•Seasonings (spices) act as antioxidants
•pepper, cloves (karanfil), allspice (yenibahar)and cinnamon ,Garlic and onion .
•aqueous smoke solution:to provide a smoked flavour.
•Sodium Nitrite/ Sodium Nitrate
• sodium nitrite (or nitrate): colour and flavour
• oxidative stability: by preventing lipid oxidation
•addition is highly regulated due to the possible risk of formation of N-nitrosamines.
•In Canada, 200 ppm (20 g per 100 kg;
United States, in all products except bacon: 200 ppm
•addition is highly regulated due to the possible risk of formation of N-nitrosamines.
•In Canada, 200 ppm (20 g per 100 kg;
United States, in all products except bacon: 200 ppm;
•additional additives for Northern type sausages
-phosphates (0.5%) Tripolyphosphates, hexametaphosphates, most widely used, to increase the water-holding capacity of cured meat products.
-Alkaline phosphates: increase the pH, solubilizing muscle proteins to impart the water-retention action.
– increase in product yield),
– phosphates improve the cured meat flavour by retention of natural juices and by reduction of oxidative rancidity.
-glucono-δ-lactone (GdL, 0.5%): fast chemical acidulation for products with a short shelf-life
Culture
•Most common commercial cultures
•Frozen cultures: (US), Cell densities, 108 to 109 cells per ml.
-70 ml can: 150 kg of sausage batter.
-dry ice and to store the cans at _40°C or below.
-The cans should be thawed in cold water prior to use.
•Lyophilized cultures:
•- less common
•Sausage Making
Comminution( grinding) or Chopping
•Raw materials and additives, including microbial starters: under vacuum, in a mincer or ‘cutter’.
•knives that rotate rapidly (1–3 × 103 r.p.m.), producing a batter in a bowl that rotates slowly (10–20 r.p.m.)
•relative speeds, knives and bowl, determine the fat particle size and are optimized to produce a batter within less than 5 minutes at temperatures ≤2 °C,
• meat grinder Bowl chopper
Stuffing
•the batter is immediately stuffed under vacuum into natural, semisynthetic (collagen) or synthetic casings that are permeable to water and air, and both ends are clipped.
•The sausage diameter (e.g. 2–15 cm)
SAUSAGE CASINGS
Animal Casings
•the oldest of packaging matls for sausage
•the collagen is hardened and rendered less soluble by the application of salt.
•Initially, as the collagen is exposed to heat and drying, it becomes less permeable to moisture.
•The sheep casings are the smallest in diameter and are also the most tender.
Manufactured Collagen Casings
•manufactured casing: collagen.
•collagen casing: Alginate Casing, Cellulose Casings from high-grade wood pulp, Plastic casings, polyethylene or a polyamide (Nylon).
•The collagen is solubilized and later extruded and hardened
Ripening ( Fermentation + others )
•hung in racks, put into natural or, mostly, air-conditioned fermentation chambers at high RH.
•Thermocouples and pH probes inserted directly into product samples… a computer….constant monitoring…recording…. feed-back control: no need full time operator.
•ripening in two consecutive stages:
•fermentation
• -Northern (20–24 °C/50–90%/2-3 days)
•- Mediterranean (5–24 °C/10–90%/100 h)
•- in USA( 37-40 C, 12-18 h)
•the pH at the end of fermentation should be less than 5.1, …. provide a reasonable protective barrier against most foodborne pathogens.
•Cooking, drying, and smoking
•In the USA: any pork containing sausage must be cooked to destroy Trichinae cause the disease Trichinella in humans.)(usually 60°C to 62°C)
•in Europe : raw sausages are the norm, and post-fermentation heating steps are rarely applied.
•Cooking inactivates the culture and stops the fermentation, but it also kills pathogenic microorganisms
•B) transfer to another chamber, drying for development of sensory characteristics.
•If the RH is too low, temp too high, drying will initially be rapid. …….. the surface will become dehydrated and form a hard, water-impermeable skin. This phenomenon, called case hardening,
•air RH: not more than 0.10 points below the associated aw values of the sausage, to prevent case hardening, and recommended air speeds are approximately 0.1 m s-1.
Smoking
•Northern type: oak wood (300–600 °C) to minimize the production of polycyclic hydrocarbons.
•Smoke: antimicrobial,antioxidant effects, generates specific flavour and colour components.
•Sausage Metabolism and Safety
the starting material,meat,is raw and cannot be heat-processed to inactivate spoilage or other undesirable microorganisms
•To lower redox potential ( omission of oxygen by chopping under vacuum, addition of ascorbic acid or ascorbate). This inhibits aerobic bacteria and improves the bactericidal effectiveness of nitrite, a major hurdle.
•Drying, addition of salt ( reduction in the water activity, aw •undesirable moulds on the sausage exterior is prevented by pretreatment of the casing with potassium sorbate or pimaricine solutions.
Typical Defects and Their Causes
•surface is blurred: temp of the fat was not low enough during comminution, blending and stuffing.
•sausage is deformed: too rapid drying, case-hardening, smeared fat under the casing.
•• Discoloration of the surface: too high smoking when the surface is wet; smoking with high RH; ripening with RH.
•• Discoloration inside: insufficient curing salt; insufficient oxygen removal during comminution and stuffing; too old (rancid) fat.
•• White spots (yeasts) or moulds on the surface: inefficient drying; ripening room is contaminated with yeasts and moulds.
• Too acidic taste: too high carbohydrate ,higher temp (starter culture-dependent), starter culture-specific (production of acetic acid in addition to lactic acid).
• Poor sliceability: unsatisfactory pH-drop and/or aw drop; fat smearing inhibits binding; chemical acidulants react too early (before stuffing).
• Spoilage on the surface: if high RH; micrococci, yeasts and moulds: off-odours
•Spoilage inside: too slow drying; too low initial salt concentration; highly contaminated ingredients; failure of the starter culture; too high initial pH of the meat; too low carbohydrate concentration; insufficient oxygen removal.
•MEAT CURING ( salamura, pastırma ——-ham( from pork))
• Dry curing:
•Meat rubbed with cure mixture ( 50 kg salt+ 0.5 kg nitrate + 1 kg sucrose )—— theb rubbed with sat ———- put in to cask and press for 1-2 days.
•Wet curing:
•Mixture of ( 100 kg water + 24 kg salt + 1 kg nitrate salt + 2 kg sugar ) —–boiled—-cooled ( 5 C )—poured in to cask which is containing meat—– later wash the meat with hot water—– then put in to cold water ( 10-30 minutes)
•( NO3( nitrate ) —-NO2 (nitrite)
•3NO2 + GDL ————- 2NO + HNO3 + H2O
•NO + Myoglobin —- nitrosomyoglobin ( color stability)
Pastırma
– The Turkish horsemen: by placing slabs of it in pockets on the sides of their saddles, where it would be pressed by their legs as they rode.
– This pressed meat was the forerunner of today’s pastırma, a term which literally means being pressed in Turkish, and is the origin of the Italian pastrami
• series of processes about a month.
•Fresh meat : rest at room temp. for 4-8 hours before being divided.
•salted on one side, stacked, and left for around 24 hours.
•salted on the other side, stacked and left for a further 24 hours.
•rinsed in plenty of water to remove the excess salt
•dried in the open air for a period varying between three and ten days.
•further processing, the meat is hung up to
• dry again( in the shade and spaced out
•so that the joints do not a touch one another.)
•After 3-6 days, covered with a paste of ground spices known as çemen(Trigonella foenum groecum ( buy otu tohumu ) seeds, garlic and chilli pepper mixed to a paste with a little water. ) , and left to cure for 10-24 hours in hot weather, and 1-2 days in cold weather.
•Then the excess çemen is removed,
• leaving a thin layer, and the joints
• dried again.
• Making Salami
•Ground meat+spices(garlic,redpepper,black pepper, fennel seed)+salt+starter culture(Pediococcus cerevisiae and Lactobacillus plantarum. ) …….. Curing, Incubating, Drying
•(totaly around 3 weeks)
rezene
•Curing : refrigerate for 2 days
and incubate at 28-30 C, 90% RH
Frankfurters
• originate from Frankfurt, Germany in 1487.
used interchangeably with frank, wiener and hot dog.
• 20–25 mm in D, linked in 12.5 cm lengths.
•a natural casing or a cellulose casing.
• Hot dogs; typically smoked.
•cellulose casing is removed before packaging results in skinless product( over 95% of total)
•80-90 % lean meat + 10-20 % fat + 5 % potato starch + 0.2-0.4 % red pepper + 0.2-0.4 % black pepper + 0.5 % sugar + 0.05 % nitrate + 0.02 % nitrite + 0.03 % ascorbic acid + 2.5 % salt + 20-30 % water as ice
•Process: meat + salt + nitrate + nitrite —-mix and grind —– rest ( -3 C, 12 hours to increase water holding capacity) — add remaining spices and ice —grind— add fat—- add ascorbic acid——- fill to casings—- dry at 40 C , 15-20 minutes —smoking ( 75-78 C , 35-45 minutes, horn beech wood or oak wood is used—–phenol and phenol aldehyde is produced to have antimicrobial and antioxidative effect) ——- dip into water , 80 C, 15-20 minutes —–treat with cold waters—ready to sell

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