EFFECT OF INOCULATION ON THE QUALITY OF DRY-CURED HAMS

Twenty paired pork legs were vacuum tumbled with cure adjuncts at 18 revolutions per minute (RPM) and 94.5 k Pa vacuum for 30 min. Following 40 days of curing, those legs from the right side were inoculated (I) with a mixed culture of microorganisms obtained from commercially cured ham and those from the left were not inoculated (C). All samples were evaluated at 56 days and 73 days for sensory traits. Water, NaCl, NO₃ and NO₂ determinations were also made. Inoculation increased (P <0.05) cured color development of uncooked samples cured for 56 days. Cure time and inoculation had no effect (P > 0.05) on juiciness or flavor. Aging increased tenderness (P <0.05), as evidenced in the samples at 73 days, and reduced the moisture content. Microbial inoculation did not accelerate the cure penetration rate and had no consistent effect on the amount of NO₃ and NO₂.     

Characteristics of Dry-Cured Hams as Affected by Needle Tenderization and Vacuum Packaging

Needle tenderization of skinned hams accelerated salt absorption and weight loss and shortened curing time for dry-cured hams. Vacuum packaging of hams after they achieved an 18% weight loss prevented most additional weight loss thus yielding a higher percentage of moisture and a lower percentage of salt than in nonpackaged hams. Total bacterial and lactobacilli counts were higher in packaged hams but did not affect internal appearance scores or sensory evaluation scores. In general, the use of needle tenderization and vacuum packaging was helpful in reducing curing and aging time and in controlling yields in dry-cured hams.     

Accelerated production of dry cured hams

Ten uncured legs from the right side of the sampled pork carcasses (Study A) were vacuum tumbled with the cure adjuncts for 30 min (T) and 10 counterparts from the left side were tumbled 30 min, rested 30 min and tumbled an additional 30 min (TRT). Evaluations were conducted at 40 and 70 days after cure application for color, taste attributes, percentage moisture, percentage salt and NO(3)(-) and NO(2)(-) content. Study B was the same except that 18 legs were boned, tumbled and cured for 40, 56 and 70 days. The TRT samples (Study A) at 40 days sustained less color fading (P < 0.05) during cookery, but no differences (P > 0.05) existed among the uncooked hams. Increased cure time enhanced moisture loss and salt content (Study A) and color retention during cookery (Study B). The TRT samples had increased moisture loss and salt content (Study A).     

Effect of Tumbling and Tumbling Time on Quality and Microflora of Dry-Cured Hams

Thirty-two intact hams were utilized to study the effects of tumbling and tumbling time (1 hr continuous, 3 hr intermittent, 6 hr intermittent) on the quality and microflora of intact dry-cured hams. Tumbled hams had higher salt concentrations, lower moisture percentages, and showed more muscle separation and excessive surface drying. Sensory panel scores were similar for all treatments except that 3 hr intermittently tumbled hams had higher salt and lower overall satisfaction scores. Tumbling significantly accelerated salt and nitrite penetration during the Fust 2 wk of curing but had little subsequent effect. Tumbled hams generally had lower microbial counts; however, after aging all hams were of acceptable microbial quality.     

Survey of naturally and conventionally cured commercial frankfurters, ham, and bacon for physio-chemical characteristics that affect bacterial growth

Natural and organic food regulations preclude the use of sodium nitrite/nitrate and other antimicrobials for processed meat products. Consequently, processors have begun to use natural nitrate/nitrite sources, such as celery juice/powder, sea salt, and turbinado sugar, to manufacture natural and organic products with cured meat characteristics but without sodium nitrite. The objective of this study was to compare physio-chemical characteristics that affect Clostridium perfringens and Listeria monocytogenes growth in naturally cured and traditionally cured commercial frankfurters, hams, and bacon. Correlations of specific product characteristics to pathogen growth varied between products and pathogens, though water activity, salt concentration, and product composition (moisture, protein and fat) were common intrinsic factors correlated to pathogen growth across products. Other frequently correlated traits were related to curing reactions such as % cured pigment. Residual nitrite and nitrate were significantly correlated to C. perfringens growth but only for the ham products.     

Survey of naturally and conventionally cured commercial frankfurters,ham, and bacon for physio-chemical characteristics that affect bacterial growth

Natural and organic food regulations preclude the use of sodium nitrite/nitrate and other antimicrobials for processed meat products. Consequently, processors have begun to use natural nitrate/nitrite sources, such as celery juice/powder, sea salt, and turbinado sugar, to manufacture natural and organic products with cured meat characteristics but without sodium nitrite. The objective of this study was to compare physio-chemical characteristics that affect Clostridium perfringens and Listeria monocytogenes growth in naturally cured and traditionally cured commercial frankfurters, hams, and bacon. Correlations of specific product characteristics to pathogen growth varied between products and pathogens, though water activity, salt concentration, and product composition (moisture, protein and fat) were common intrinsic factors correlated to pathogen growth across products. Other frequently correlated traits were related to curing reactions such as % cured pigment. Residual nitrite and nitrate were significantly correlated to C. perfringens growth but only for the ham products.     

LOW-FAT, NO ADDED SALT IN RESTRUCTURED BEEF STEAKS WITH VARIOUS BINDERS

This research investigated technology for the development of a low-fat restructured beef steak devoid of added salt with texture similar to intact muscle. Low-fat (10%), low-sodium restructured beef steaks made from closely trimmed, flaked beef round muscles and tumbled with or without a binding agent were compared to boneless top loin steaks (5–6% fat). Boneless top loin steaks had greater (P < .05) shear resistance, cohesiveness, juiciness, overall desirability, percentage moisture (raw) and percentage protein (cooked) than restructured steaks. Steaks made with 3.0% modified potato starch had slightly more juiciness and moisture content (cooked) and lower expressible fluid content than all other restructured samples. Product made with 1.0% microcrystalline cellulose had lower (P < .05) juiciness scores than top loin steaks and restructured steaks made with no additives or modified potato starch. Use of 0.25% kappa-carrageenan or 1.5% surimi increased (P < .05) sensory scores for off-flavor. Steaks made with 1.5% surimi also had lower (P < .05) sensory scores for overall desirability.     

A RESEARCH NOTE CHEMICAL, PHYSICAL, AND SENSORY CHARACTERISTICS OF COLOR MODIFIED PORK RESTRUCTURED CHOPS

Restructured pork chops were manufactured from the lean tissue of dressed sows that were color modified(CM) with a potassium buffer rinse to attain lighter appearance. This product was compared with counterpart samples that were not color modified(C). Measurements included CIE L*, a*, b* values, visual traits, sensory traits, shear force, pH, and percentage of moisture, fat, protein, protein solubility, and cooking loss. The CM samples were lighter colored (P<0.05), exhibited less (P<0.05) flavor intensity, had a higher (P<0.05) pH, and sustained less (P<0.05) cooking loss. No differences (P>0.05) between the CM and C samples were found in juiciness, tenderness, Warner-Bratzler shear force, and soluble protein. The CM samples exhibited less protein content and lower Lee-Kramer shear force values. Results confirm that sow meat can be lightened without adversely affecting functional properties and taste attributes of restructured pork chops.     

EFFECT OF CURING INGREDIENTS, SKINNING, AND BONING ON YIELD, QUALITY, AND MICROFLORA OR COUNTRY HAMS

Green hams were left intact, partially skinned, fully skinned, and fully skinned and boned. They were dry-cured with or without nitrate and aged 3 months. The presence of nitrate had no effect on the variables studies. Percent moisture loss and accompanying weight loss increased with each further removal of protective fat and skin. Percent residual salt was in proportion to weight loss. Residual nitrite was low for all groups Color and aroma scores were similar for all groups. General appearance scores, however, were lowest for the drier boneless group. Shear values were greatest while organoleptic flavor and over-all satisfaction scores were lowest in the boneless group. Tenderness scores were similar for the skinless and boneless group but both were lower than for the intact or partially skinned groups. In general, microbial counts were highest for surface samples from completely skinned fresh hams and lowest for partially skinned fresh hams. Higher counts were obtained for core samples from boneless fresh hams than for intact hams. Aerobic (26° and 37°C), lactobacilli, enterococci. streptococci. yeast and mold surface, and core counts tended to decrease during the manufacture of aged dry-cured hams. No trends in counts due to ham group or cure treatment were observed during the manufacturing process. At the end of the aging period none of the hams contained bacteria of public health significance. Aged dry-cured hams of acceptable microbial quality can be manufactured using intact, partially skinned, skinned or boneless fresh hams without potassium nitrate as part of the cure mixture.     

Effect of nitrate and nitrite curing salts on lipolysis in dry sausages produced using a rapid fermentation process

 The effect of nitrite and nitrate curing salts on lipolysis in a typical non-smoked Spanish sausage (salchichón), manufactured using a rapid dry fermentation process, was studied. From the results obtained, one could deduce that nitrite and nitrate per se do not affect the endogenous hydrolysis of the lipids during the rapid fermentation process used to produce dry sausage. Polyunsaturated fatty acids (PUFA) are liberated in greater quantities than monounsaturated (MUFA) and saturated (SFA) ones, which suggests that they are derived mainly from phospholipids. The samples that contained nitrate curing salts contained more free fatty acids (FFA) (548 mg/100 g) than those that contained nitrite curing salts (478 mg/100 g) at the end of the fermentation step, as a consequence of having undergone a preripening stage, during which significant amounts of FFA are formed. However, at the end of the ripening process, although there is a significant increase of FFA levels in all the sausages, no significant differences between samples with nitrite and those with nitrate could be found. This result could have occurred if the oxidative effects of the samples with nitrate balanced the antioxidative properties of nitrite, such that, through different processes, similar concentrations of FFA are obtained at the end of ripening. Phospholipids (PL) and free fatty acids (FFA) are the lipid fractions that undergo the most important changes during ripening. PL are moderately degraded during the drying process, probably due to the combined effects of the drying temperature (10°C) and the presence of starters. However, this degradation does not differ significantly between the samples that contain nitrite and and those that contain nitrate in each control. Received: 23 July 1997 / Revised version: 8 October 1997     

Effect of nitrate and nitrite curing salts on lipolysis in dry sausages produced using a rapid fermentation process

 The effect of nitrite and nitrate curing salts on lipolysis in a typical non-smoked Spanish sausage (salchichón), manufactured using a rapid dry fermentation process, was studied. From the results obtained, one could deduce that nitrite and nitrate per se do not affect the endogenous hydrolysis of the lipids during the rapid fermentation process used to produce dry sausage. Polyunsaturated fatty acids (PUFA) are liberated in greater quantities than monounsaturated (MUFA) and saturated (SFA) ones, which suggests that they are derived mainly from phospholipids. The samples that contained nitrate curing salts contained more free fatty acids (FFA) (548 mg/100 g) than those that contained nitrite curing salts (478 mg/100 g) at the end of the fermentation step, as a consequence of having undergone a preripening stage, during which significant amounts of FFA are formed. However, at the end of the ripening process, although there is a significant increase of FFA levels in all the sausages, no significant differences between samples with nitrite and those with nitrate could be found. This result could have occurred if the oxidative effects of the samples with nitrate balanced the antioxidative properties of nitrite, such that, through different processes, similar concentrations of FFA are obtained at the end of ripening. Phospholipids (PL) and free fatty acids (FFA) are the lipid fractions that undergo the most important changes during ripening. PL are moderately degraded during the drying process, probably due to the combined effects of the drying temperature (10°C) and the presence of starters. However, this degradation does not differ significantly between the samples that contain nitrite and and those that contain nitrate in each control. Received: 23 July 1997 / Revised version: 8 October 1997     

Effect of nitrate and nitrite curing salts on the generation and oxidation of fatty acids in non-fermented sausages

 The purpose of this work was to study the effect of nitrate and nitrite curing salts on FFA generation and oxidation during an industrial process of country-style dry sausages (35/40 mm casing diameter) to determine their role in flavour development. The pH values of the sausages are around 6.0 during the dry processing. FFA liberation is two or three times greater in the samples with nitrite than in those with nitrate. However, the intensity of the oxidative phenomena during the drying process does not depend on the quantity of FFA. In the samples with nitrate more intense oxidative phenomena take place, which lead to a stronger typical dry-cured flavour than in samples with nitrite. Received: 14 July 2000 / Revised version: 15 September 2000     

Salt, Moisture and Aging Time Effects on the Viability of Trichinella spiralis in Pork Hams and Shoulders

SUMMARY– Twenty-four weanling pigs were infested with Trichinella spiralis , by dosing with trichina larvae. The hogs were raised to market weight and slaughtered. Lean samples from each ham and shoulder were digested in a pepsin-HCI solution and microscopically examined. The samples contained respectively an average of 192 and 175 larvae per gram.
The hams and shoulders were dry-cured for 2 days per pound, using 8 pounds of cure per 100 pounds of meat. The mixture contained salt, sugar, potassium nitrate, and sodium nitrite. After being cured, the meat was hung for 30 days for salt equalization, rinsed, allowed to dry, smoked for approximately 24 hr at 90 to 100°F, and aged at 75°F.
Cores were taken from randomly selected hams and shoulders at weekly intervals and analyzed for salt and moisture while part was digested and examined for live trichinae. Live trichinae persisted through the curing and salt equalization periods but began to be reduced in number after one week of aging. Samples taken from hams and shoulders aged for one month were found to be void of any live trichina larvae.
Meat from similar samples was force-fed to rats for 5 days. After 8 weeks the rats were sacrificed and the carcasses digested and examined. No trichina larvae were found.     

Porcine Aminopeptidase Activity as Affected by Curing Agents

The effect of common curing agents (salt, nitrate, nitrite, ascorbic acid and glucose) on porcine muscle leucyl, arginyl, alanyl, pyroglu-tamyl and tyrosyl hydrolyzing activities was studied. Salt, ascorbate and nitrite had inhibitory effects on most enzyme activities. All activities decreased as salt increased (to 1.25 M) and/or water activity decreased (from 1.00 to 0.81). Nitrite inhibited only alanyl, pyroglu-tamyl and tyrosyl hydrolyzing activities. An in-vitro study using model conditions of three stages of dry-curing of ham, revealed that leucyl hydrolyzing activity may be important through the complete process. Other enzymes may also be involved in later stages of curing but are less important.     

Effect of added water, sodium erythorbate and storage time on the functional properties of prerigor beef preblends in a model system

Singular and combined effects of added water, sodium erythorbate and storage time on salt soluble protein extractability, bacteriological and chemical characteristics of preblended hot-boned beef were evaluated. Waterholding and gel forming capacities of preblended hot-boned beef containing either 0, 10 or 20% added water were determined. Significant interactions between added water level and storage time on microbial counts and between sodium erythorbate level and storage time on thiobarbituric acid values and residual nitrite levels were noted. The presence of sodium erythorbate resulted in a more (P < 0·05) rapid rate of nitrite disappearance, but it did not affect (P > 0·05) microbial counts. Salt-soluble protein extractability was not affected (P > 0·05) by added water, but more protein could be extracted with increasing storage time. A trend existed to suggest that the presence of added water in the meat preblends slightly improved the gel formation and waterholding capacities.     

Salt and Aging Time Effects on the Viability of Trichinella spiralis in Heavy Dry-cured Hams and Shoulders

SUMMARY: 28 pigs weighing approximately 100 lb were dosed with 10,000 to 15,000 excysted trichina larvae, grown to 285 lb and sacrificed. Fresh lean samples from one ham and shoulder per carcass were digested in a pepsine-HCI solution and microscopically examined to determine infection rates. 24 of the more heavily infected hams and shoulders then were selected for further observations. The hams and shoulders were dry-cured for 2 days per lb, using an 8% cure applied in 3 equal applications at 5-day intervals. The cure contained salt, sugar, potassium nitrate and sodium nitrite. After curing, the meat was placed in salt equalization for 30 days, smoked for 24 hr at 100°F and aged at 75°F until termination of the study. Cored lean samples were taken from 8 hams and shoulders at weekly intervals after salt equalization and analyzed for salt concentrations and viability. Viable trichinae persisted throughout curing, salt equalization, smoking and 2 weeks of aging. Samples taken from hams and shoulders after 3 weeks of aging were found to be free of any live trichinae. Similar lean samples were taken at this time and force fed to rats for 5 days. After 8 weeks on a commercial ration the rats were sacrificed, artificially digested and examined. No trichina larvae could be recovered.     

Effects of Electrical Stimulation, Boning Time and Cooking Method on Beef Roasts

Sixteen steer carcasses were selected to study effects of electrical stimulation, boning time and cooking methods on palatability traits, cooking loss and chemical composition of beef biceps femoris muscle. Eight carcasses were electrically stimulated and eight carcasses served as controls. The biceps femoris muscle was removed from one side of each carcass within 2 hr of exsanguination and from the remaining side following a 48-hr chill. Muscles were subdivided and cooked in either a convectional electric or a microwave oven. Electrical stimulation resulted in longer (P < 0.01) sarcomeres for cooked product but did not affect palatability traits, cooking loss or chemical content. Hot boning reduced (P < 0.01) cooking loss and tenderness, resulted in less (P < 0.05) total, soluble and insoluble collagen and increased the juiciness score and moisture percentage when compared with 48-hr boning. Microwave cooking produced a greater (P < 0.01) cooking loss and a higher shear force value than convectional electric cooking.     

Distribution and Rate of Migration of Curing Ingredients (Nitrite, Salt, Glucose) in Pork Tissue as Affected by Electrical Stimulation

The effect of electrical stimulation of pork carcasses on distribution and rate of migration of curing ingredients (nitrite, salt, glucose) was investigated. Sixty cylindrical triceps brachii muscle samples were prepared at 24 hr post-stimulation from three pigs (left side stimulated; right side control, not stimulated) and determination for nitrite, salt and glucose were made at 24, 48 and 72 hr post-curing at each of four cylindrical segment depths of 1.25 cm each. The analysis of variance indicated that electrical stimulation caused significant (P < 0.01) improvement in absorption and migration of curing ingredients (nitrite, salt, glucose) into all depths of the pork cylinder.     

肉类安全:当心亚硝酸盐——引起亚硝酸盐超标的原因分析

<正> 如果你在网上的搜索栏里输入“亚硝酸”或“亚硝酸盐”,就会找到上万条有关亚硝酸盐中毒的报道。针对前一时期全国发生的多起亚硝酸盐食物中毒事件,卫生部发布的2004年第四次食品卫生预警公告,要求严防亚硝酸盐食物中毒事件的发生。究竟是什么原因造成亚硝酸盐超标呢? 正确认识亚硝酸盐 亚硝酸盐是一种世界各国都普遍使用的食品添加剂,因其能在肉食品中产生强致癌物亚硝胺,因而必须严格控制     

Effects of Boning Time, Mechanical Tenderization and Partial Replacement of Sodium Chloride on the Quality and Microflora of Boneless Dry-Cured Ham

SEVENTY-TWO HAMS were utilized to study the effects of KCl replacement level (100:0, 70:30, 50:50 ratios of NaCl and KCl), boning time and mechanical tenderization on the quality and microflora of boneless dry-cured hams. Boning time had no effect on palatability or final yield. Hotboned hames had higher levels of residual nitrite and slightly higher microbial counts. Mechanical tenderization improved tenderness and microbial quality. However, tenderized hams had lower flavor preference and overall satisfaction scores. The replacement of NaCl with KCl at a level of 30% had no effect on palatability or microbial quality. NaCl replacement at a level of 50% severely decreased palatability and increased microbial numbers.