Effect of fat level and ripening temperature on biochemical and sensory characteristics of naturally fermented Turkish sausages (sucuk)

Changes in chemical and sensory characteristics of naturally fermented Turkish sausages during ripening were evaluated for three fat levels (10, 20 and 30%) and two different ripening temperatures, i.e. 20–22 and 24–26 °C. Fat level, ripening temperature and time affected total acidity, free fatty acids (FFA) and thiobarbituric acid (TBA) values. Both higher fat content and higher temperature resulted in higher FFA and TBA values during ripening, indicating high lipolytic and oxidative activity. TBA values showed an increase from the first to the ninth day, but were lower at 20–22 °C than at 24–26 °C. High fat level and temperature adversely affected rancid flavor and overall acceptability.     

Effect of fat level and storage conditions on quality characteristics of traditional Greek sausages

Traditionally-processed Greek sausages were produced with three different fat levels (10, 20 and 30% fat). Some sausages were air dried (23-28°C, 64-76% RH) for 2h and stored at 3-7°C and 65-75% RH. The rest were immediately stored in a ripening room at 13-15°C, 85-95% RH and 0.1m(-1)s air velocity. Fat level affected the composition of the sausages, their weight loss, brine concentration, water activity, colour and sensory attributes. Sausages with 20% fat had the highest scores for all sensory attributes. Sausages with 30% fat were very light, yellow, soft and too fatty when grilled, whereas those with 10% fat were dark and very hard after grilling. Storage conditions affected the microflora, pH, weight losses and water activity, but had no effect on composition, colour and sensory attributes. Sausages stored in the ripening room had a rapid increase in lactic acid bacteria count and lower pH than those in cold storage. Storage of traditional sausages for up to 7 days in a ripening room, similar to that used for fermented sausages, is considered beneficial. ?     

Fat effect on physico-chemical, microbial and textural changes through the manufactured of dry-cured foal sausage Lipolysis, proteolysis and sensory properties

The effect of fat content on chemical traits related to dry-curing process (pH, moisture and water activity), color and textural properties and changes of free fatty acids and amino acids compositions during the processing of foal dry-cured sausages were studied. For this purpose, three batches (20 units per batch) of dry fermented sausages with different pork back fat content (5%, 10% and 20%) were manufactured; low fat (LF), medium fat (MF) and high fat (HF), respectively. Samples at 0days (mix before stuffing), and after 7, 14, 28, 42 and 49days of ripening were taken. The fat level affected color and textural parameters at the end of the process, showing dry-cured foal sausage with the higher level of fat, the highest values of luminosity and the least hardness. No significant differences (P>0.05) among batches were detected on total viable counts, lactic acid bacteria and Microccaceae during the process. Regarding lipolysis and lipid oxidation it can be deduced that the increase in the fat level encouraged the production of free fatty acids and 2-thiobarbituric acid reactive substances. At the end of the ripening individual free fatty acids followed this order: oleic, palmitic, linoleic and stearic acid, representing 82-95% of the total free fatty acids. Final level of TBARS index was in the worst case of 1.23mg MDA/kg of sausage. On the contrary, the batch with lesser fat content showed the highest levels of free amino acids at the beginning and at the end of the process, showing final values of 1.6%.     

Effect of carrageenan level and packaging during ripening on processing and quality characteristics of low-fat fermented sausages produced with olive oil

Eight low-fat fermented sausages were produced with partial replacement of pork backfat with olive oil. The total fat content of the sausages was 10% of which 8% was animal fat and 2% was olive oil. The sausages were produced with two types of carrageenan (ι- and κ-) in four levels (0%, 1%, 2% and 3%). ι-Carrageenan had a better effect (p<0.05) than κ-carrageenan on such characteristics as pH, weight loss and lipid oxidation of the sausages, as well as, on sensory attributes. Low-fat fermented sausages with κ-carrageenan had the same (p>0.05) firmness as high-fat commercial sausages (control). The carrageenan level of 3% negatively affected the firmness of the sausages. In a 2nd experiment, a high-fat control (30% total fat) and three low-fat fermented sausages (10% total fat) with olive oil were produced with three levels of ι-carrageenan (0%, 1% and 2%). Low-fat sausages were vacuum packed for the last two weeks of ripening. ι-Carrageenan added at levels up to 2% had a positive effect (p<0.05) on the physicochemical and microbiological characteristics of the low-fat fermented sausages. The application of vacuum packaging over last two weeks of ripening improved the physicochemical and microbiological characteristics of the sausages and resulted in sensory attributes equal to or better than the high-fat controls.     

An innovative method for the preparation of mum (Thai fermented sausages) with acceptable technological quality and extended shelf-life

Freshly-manufactured mum sausages were assigned to two processing methods (process I: stored at ～30 °C for 14 days; process II: stored at ～30 °C for three days, vacuum-packaged, and stored at 4 °C until day 28). Physicochemical, microbial, textural, and sensory properties of samples were analysed. The results showed that dehydration was more intense in process I samples, and resulted in lower moisture content and water activity. Significant decreases in pH values, and increases in lactic acid were observed in both samples by day 3. The total microflora and lactic acid bacteria counts increased rapidly during the fermentation and then decreased while the Enterobacteriaceae counts decreased steadily. Too much dehydration resulted in tough textures and unacceptable sensory qualities for process I samples. In conclusion, after three days of fermentation, with vacuum-packaging, ripening and storage at 4 °C up to 28 days, it is possible to produce mum sausages with better qualities and an extended shelf life.     

Chopping temperature effects on the characteristics and chilled storage of low- and high-fat pork Bologna sausages

The object of this study was to investigate the influence of chilled storage (2 °C) and final chopping temperatures (8, 15 and 22 °C) on the characteristics and stability of Bologna sausage containing two levels of fat (8.5 and 23%). When the fat level was reduced there was a significant decrease in penetration force and an increase in both cooking and purge loss. A lower chopping temperature reduced purge loss during chilled storage. In general, an inverse relationship was found between chopping temperature and penetration force. Chopping temperature did not influence total aerobic count, but during chilled storage counts were significantly higher in the low fat sausages.     

Effect of fat level and partial replacement of pork backfat with olive oil on processing and quality characteristics of fermented sausages

Six formulations of dry fermented sausages were produced in three replications with three initial fat levels (30, 20 and 10%) and two levels (0 and 20%) of pork backfat replacing olive oil. After 4 weeks of fermentation and ripening the fat content of the treatments with 30, 20 and 10% fat level ranged from 38.86 to 43.60%, 25.56 to 26.86% and 19.01 to 20.14%, respectively. Fat level affected (P<0.05) the weight losses, the chemical composition, the Gram −ve bacterial count, the lightness, the texture and the appearance of fermented sausages. Replacing 20% of pork backfat by olive oil affected (P<0.05) the lightness and yellowness of sausages. Fat-reduced sausages without olive oil and low-fat sausages with olive oil had the highest score for odour and taste. However, the appearance of fat-reduced sausages was just acceptable while that of low-fat sausages was unacceptable, because the surface was intensively wrinkled and case hardening had developed. Further research is needed to improve the appearance of these sausages.     

The bacteriological quality, fat and collagen content of minced beef at retail level

Samples of minced (ground) beef were purchased on three occasions from seven supermarkets and eleven butcher's shops in one geographical area during winter. Total viable counts (at 37°C and 20°C), numbers of Enterobacteriaceae (at 37°C) and Escherichia coli biotype I were similar between shop type. No Salmonella spp. were detected. In general, bacterial counts were lower than in a similar survey four years previously. The fat and collagen content of the samples was also determined. In a previous survey, 37% of samples contained more than 25% fat, while, in this survey, only 17% of the samples exceeded that level. Collagen levels in the mince at retail ranged from 1·4% to 4·4% (1·5% to 5·1% on a wet fat-free basis).     

Influence of hygienic quality of raw materials on biogenic amine production during ripening and storage of dry fermented sausages

The effect of the hygienic status of raw materials on biogenic amine production during ripening and storage (at 4 and 15 degrees C) of fermented sausages was studied. Two portions of fresh lean and back fat pork were stored for 5 days at -20 degrees C (treatment A) and at 4 degrees C (treatment B), respectively. Raw materials of treatment A maintained their hygienic quality high and low amine content. Raw materials of treatment B showed from 1 to 3 log (CFU/g) higher microbial counts and a biogenic amine index near 50 mg/kg, indicating poorer hygienic quality. The quality of raw materials influenced the composition and the concentration of biogenic amines produced during the ripening sausages. Sausages of treatment A (A-sausages) showed a large accumulation of tyramine (up to 100 mg/kg dm) followed by putrescine and cadaverine (<15 mg/kg). In contrast, B-sausages resulted in earlier and much greater amine production, and cadaverine, tyramine, and putrescine levels were 50-, 2.6-, and 6.5-fold higher than those of A-sausages. Other biogenic amines, such as octopamine, tryptamine, phenylethylamine, and histamine were also produced in B-sausages. The higher proteolysis and the lower pH of B-sausages might have favored the decarboxylase activity of microorganisms. Biogenic amine contents of sausages during storage depended on the raw materials used and storage temperature. No significant modification on the amine contents was observed during the storage of A-sausages at either temperature. Greater changes occurred in B-sausages stored at 15 degrees C than in those stored at 4 degrees C. Higher temperatures favored proteolytic and decarboxylase reactions, resulting in increased amine concentrations after storage.     

Changes in biogenic amine and polyamine contents in slightly fermented sausages manufactured with and without sugar

The effect of sugar omission on biogenic amine contents of slightly fermented sausages during ripening and storage was evaluated. Two batches of spontaneously fermented sausages were produced with and without sugars in two different trials at pilot-plant scale. Ripened sausages were stored at 4 and 19°C for a further 20 days. Tyramine and cadaverine were the main amines formed during ripening, their contents being significantly higher in batches without sugar. High counts of LAB and Enterobacteriaceae could be associated with the production of tyramine and cadaverine, respectively. The occurrence of putrescine depended on the trial and batch. Sausages without sugar contained more putrescine than those with sugar in trial 1, but this was not repeated in trial 2, in which a high production of agmatine occurred. Tryptamine and phenylethylamine were only detected in the later stages of ripening, their contents also being higher in sausages without sugar. Biogenic amine contents generally rose during storage at 19°C, the increase being especially important for cadaverine and tyramine in sausages without sugar. Levels of spermidine and spermine remained constant during ripening and decreased slightly during storage. Sugar omission is not recommended because it might increase biogenic amine accumulation during the manufacture and storage of slightly fermented sausages.     

The effects of high hydrostatic pressure at subzero temperature on the quality of ready-to-eat cured beef carpaccio

We compared the application of high hydrostatic pressure (HHP) on unfrozen carpaccio (HHP at 20°C) and on previously-frozen carpaccio (HHP at -30°C). HHP at 20°C changed the color. The pressure increase from 400 to 650MPa and the time increment from 1 to 5min at 400MPa increased L* and b*. a* decreased only with 650MPa for 5min at 20°C. The prior freezing of the carpaccio and the HHP at -30°C minimized the effect of the HHP on the color and did not change the shear force, but increased expressible moisture as compared to the untreated carpaccio. HHP at 20°C was more effective in reducing the counts of microorganisms (aerobic total count at 30°C, Enterobacteriaceae, psychrotrophs viable at 6.5°C and lactic acid bacteria) than HHP at -30o C. With HHP at 20°C, we observed a significant effect of pressure and time on the reduction of the counts.     

Effect of fat level on physicochemical,volatile compounds and sensory characteristics of dry-ripened “chorizo” from Celta pig breed

A traditional Spanish dry-ripened sausage “chorizo” from Celta pig breed was formulated with 10, 20 and 30% of back fat (LF, MF and HF, respectively). An increase in fat content significantly affected the chemical composition of the sausages at the end of ripening (higher fat content and lower protein content and moisture) and physico-chemical parameters (lower pH, a_w, hardness, springiness and chewiness and higher TBARS index, L*, a* and b* values). With the increase of fat in the sausage formulation a higher total content of free fatty acids (FFA) was also obtained, showing a greater lipolysis than in LF sausages. All these parameters were significantly affected by ripening time. A lower total content of volatile compounds were found in HF sausages, being detected 3 alcohols, 4 aldehydes, 12 esters, 3 ketones, 7 aliphatic and 4 aromatic hydrocarbons. Sensorial analysis showed differences for fat level and fat-lean cohesiveness within appearance attributes; odour intensity and spices odour within odour attributes and hardness within texture attributes.     

Effect of refrigerated and frozen storage on the survival of Campylobacter jejuni in cooked chicken meat breast

This experimental work aimed to examine the survivability of Campylobacter jejuni in cooked chicken breast under several conditions: storage for 1, 3, and 7 d at refrigerated temperatures (4 °C) and for 20 d at frozen temperatures (-18 °C). In addition, storage at ambient temperature (26 to 28 °C) was involved. Chicken samples were inoculated with a mixed culture of C. jejuni strains (ATCC: 29428 and 33219) of known concentrations (50 and 500 CFU/g). Bacterial cells were recovered and enumerated using standard procedure (Preston method). Bacteria were not detected in the majority of samples stored at ambient temperature. Refrigeration reduced survivals in 95, 90, and 77.5% for samples inoculated with 500 CFU/g and kept for 1, 3, and 7 d, respectively. The maximum reduction reached 1 log(10) cycle for all refrigeration durations. It was observed that bacteria died in 17.5% of samples kept for 7 d at 4 °C. However, survivors in samples inoculated with 50 CFU/g were not detected in 50, 65, and 55% of samples kept for 1, 3, and 7 d, respectively. Freezing rendered survivors not detectable in 70% of samples inoculated with 50 CFU/g, while survived viable counts were reduced in 92.5% of samples inoculated with 500 CFU/g. These findings suggested that C. jejuni could be killed or just sublethally injured with or without reduction in viable counts under the investigated storage temperatures, which may indicate the ability of this bacterium to survive in chicken meat stored under refrigerated and frozen conditions.     

Use of ionizing radiation doses of 2 and 4kGy to control Listeria spp. and Escherichia coli O157:H7 on frozen meat trimmings used for dry fermented sausage production

This study evaluated survival of Listeria spp. (four-strain mixture of Listeria innocua plus a non-virulent Listeria monocytogenes strain) and Escherichia coli O157:H7 strain ATCC 43888 during fermentation and ripening of Greek dry sausages formulated from meat and pork fat trimmings previously inoculated with ca. 6logcfug(-1) of the target bacteria and then irradiated in frozen (-25°C) blocks at doses of 0 (control), 2 or 4kGy. Irradiation of the trimmings at 2kGy reduced initial contamination of the sausage batter with Listeria and E. coli O157:H7 by 1.3 and 2.0 logcfug(-1), respectively, while the corresponding reductions at 4kGy were 2.4 and 5.5 logcfug(-1), respectively. In fact, E. coli O157:H7 was eliminated by 4kGy at formulation (day 0) as compared to 7 and 21 days of ripening in samples treated at 2 and 0kGy, respectively. Despite the fact that irradiation assisted in faster declines of listeriae during fermentation, these bacteria showed a strong tailing during ripening, which was more pronounced in sausages irradiated at 4kGy. As a consequence, survival of Listeria in 28-day sausages irradiated at 2 or 4kGy was ca. 2 logcfug(-1) and similar (P>0.05) to that in non-irradiated samples. Irradiation showed promise for controlling E. coli O157:H7 and, to a lesser extent, L. monocytogenes in fermented sausages.     

Effects of temperature, oxygen exclusion, and storage on the microbial loads and pH of packed ostrich steaks

Ostrich steaks (96) were packed (air or vacuum) and stored at 4°C or 10°C. Microbiological loads (total viable counts - TVC, psychrotrophic, Enterobacteriaceae, lactic acid bacteria - LAB, Pseudomonas and fluorescent Pseudomonas) and pH values were determined at 0, 3, 6 and 9 days. High counts (8.0-10.2 log(10)cfu TVC/g) were observed at day 9, possibly as a consequence of the initial high microbial load (range 4.9-5.4 log(10)cfu TVC/g) and pH (average 6.7). Temperature and sampling day significantly influenced all microbial counts. Gas atmosphere had a small or negligible influence on levels of Enterobacteriaceae and LAB. For most microbial groups temperature significantly influenced bacterial levels up to day 6 of storage, while gas atmosphere had a significant effect at days 6 and 9. Both effects (temperature and gas atmosphere) were significant factors from day 0 for fluorescent Pseudomonas. Samples vacuum-packed and stored at 4°C showed the lowest microbial loads at day 9. Only for these samples was no sensory rejection observed at the end of the experiment.     

Comparison of Bacteriological Status During Ripening of Traditional Fermented Sausages Filled into Different Diameter Artificial Casings

The ripening process of fermented sausages is affected by diameter and type of sausage casings, and depends on changes in the microflora, important from hygienic and technological aspects. The aim of this study was to compare the bacteriological status sausages which were stuffed in artificial collagen sausage casings of different diameters (35 mm and 60 mm) during ripening and drying. The sausage stuffing was the same, as was the uncontrolled ripening conditions. In bigger diameter sausages, significantly higher average total bacterial count, enterobacteria and lactic acid bacteria counts were found than in smaller diameter sausages.     

Microbiological profiles, pH, and titratable acidity of chorizo and salchichón (two Spanish dry fermented sausages) manufactured with ostrich, deer, or pork meat

Microbial counts, pH, and titratable acidity were determined in 102 Spanish dry fermented sausages (chorizo and salchichón) made with ostrich, deer, or pork meat. Average microbial counts (log CFU per gram) varied from 5.46 +/- 0.24 to 8.25 +/- 0.80 (total viable counts), from 4.79 +/- 0.36 to 7.99 +/- 0.20 (psychrotrophs), from 0.00 +/- 0.00 to 0.99 +/- 1.10 (undetectable values were assumed to be zero) (Enterobacteriaceae), from 0.00 +/- 0.00 to 4.27 +/- 1.47 (enterococci), from 5.15 +/- 1.15 to 8.46 +/- 0.49 (lactic acid bacteria), from 3.08 +/- 0.44 to 6.59 +/- 1.76 (Micrococcaceae), from 2.27 +/- 1.53 to 5.11 +/- 1.81 (molds and yeasts), from 0.00 +/- 0.00 to 2.25 +/- 0.81 (pseudomonads), and from 0.00 +/- 0.00 to 2.78 +/- 0.46 (Brochothrix thermosphacta). Average pH and titratable acidity varied from 5.07 +/- 0.25 to 5.63 +/- 0.51 (pH units) and from 0.30 +/- 0.01 to 0.86 +/- 0.19 (% lactic acid). Both type of sausage (P < 0.05) and species of meat (P < 0.001) influenced microbial counts. Salchich6n samples showed lower average values than chorizo samples for most microbial groups (significant for Enterobacteriaceae, lactic acid bacteria, and B. thermosphacta) and titratable acidity. Sausages made from pork showed the highest microbial loads for total viable counts, psychrotrophs, Enterobacteriaceae, enterococci, lactic acid bacteria, and yeasts and molds. Higher counts were observed only for pseudomonads in ostrich sausages. B. thermosphacta levels were similar for all species of meat. The highest average pH value was observed in sausages made from ostrich meat, and the lowest titratable acidity level was found in pork sausages.     

Effect of replacing pork backfat with pre-emulsified olive oil on lipid fraction and sensory quality of Chorizo de Pamplona - a traditional Spanish fermented sausage

Six treatments of Chorizo de Pamplona, traditional Spanish fermented sausage, were manufactured under usual commercial conditions by replacing 0, 10, 15, 20, 25 and 30% of pork backfat by pre-emulsified olive oil with soy protein isolate. Sausages with 20-30% replacing level had higher (P<0.05) protein content than control as a result of the addition of soy protein isolate. The oleic acid increased (P<0.05) in sausages with 15-30% replacing level, and linoleic acid increased in sausages with 10-25%. Sausages with 10-25% of substitution had lower total SFA-stearic and higher (P<0.05) total MUFA, total PUFA, (MUFA+PUFA)/(SFA-stearic), and PUFA/(SFA-stearic). Cholesterol content showed reduction about 12-13% in sausages with 20-25% replacing level, and up to 22% in sausages with 30% replacing level. Sausages with 10-25% of substitution were acceptable from the sensorial point of view. The texture and colour instrumental measures were comparable with that of commercial products. No increments in hexanal content were observed. It is concluded that up to 25% of pork backfat can be replaced with pre-emulsified olive oil in the production of Chorizo de Pamplona fermented sausages. Higher replacing levels of pork backfat did not show nutritional advantages in relation to the fatty acid profile and were unacceptable due to considerable dripping of fat during ripening.     

Evaluation of High Pressure Processing as an Additional Hurdle to Control Listeria monocytogenes and Salmonella enterica in Low-Acid Fermented Sausages

Low‐acid fermented sausages (fuet and chorizo) were manufactured to evaluate the combined effect of high pressure processing (HPP) and ripening on foodborne pathogens. Raw sausages inoculated with a three‐strain cocktail of Salmonella ser. Derby, London, and Schwarzengrund, and a three‐strain cocktail of L. monocytogenes ser. 1/2 c and 4b were pressurized at 300 MPa for 10 min at 17 °C. Afterwards, sausages were ripened at 12 °C and 80% RH for 27 d. Salmonella counts decreased in all studied sausages during ripening. However, the application of HPP as an additional hurdle to the ripening process produced a greater decrease in the Salmonella population, showing lower counts (3 MPN/g) in ripened sausages. By contrast, lower values of L. monocytogenes counts were obtained in non‐treated (NT) than in pressurized sausages due to the delay of pH drop caused by HPP inactivation of endogenous lactic acid bacteria. After pressurization of raw sausages at 300 MPa, a discoloration of sausages was observed, coinciding with an increase in L* values.     

复合发酵剂和天然香辛料对羊肉发酵香肠品质特性的影响

通过接种复合发酵剂和添加天然香辛料,采用相同的工艺条件生产4组羊肉发酵香肠,1组为对照组,2组为接种发酵剂组,3组为发酵剂+黑胡椒组,4组为发酵剂+黑胡椒+孜然组。分别测定4个组羊肉发酵香肠在发酵成熟和贮藏过程中pH值、Aw值、水分含量及微生物的变化。结果表明:在发酵结束(即第1.5天)时,试验组和对照组的pH值、Aw值和水分含量均呈下降趋势,试验组的pH值迅速降到最低值(即5.0以下),与对照组差异显著(P<0.05);在干燥成熟过程中,试验组的pH值、Aw值和水分含量迅速下降,添加香辛料组的pH值迅速回升,同时乳酸菌数维持在108cfu/g以上水平,高于对照组,细菌总数却低于对照组;在贮藏过程中,试验组的pH值和水分含量基本保持不变,且均低于对照组,而Aw值始终呈下降趋势,细菌总数小于对照组。上述结果表明,接种复合发酵剂和添加天然香辛料能迅速降低pH值、Aw值和水分含量,有效抑制腐败菌和致病菌的生长,提高羊肉发酵香肠的品质和保藏性。