Influence of PSE pork on the quality and economics of cooked, cured ham and fermented dry sausage manufacture

PSE pork (pH(1) ≤ 5·8) and non-PSE pork (5·8 < pH(1) ≤ 6·4) were used for cooked, cured ham production and, with beef, in a 48 52 mixture for fermented dry sausage manufacture. Technological yields of PSE and non-PSE hams were, respectively, 94·0 and 105·9% which corresponded to 5·0 FMK/kg loss for the PSE ham compared to the non-PSE ham. In addition, cooked PSE ham had a poorer organoleptic quality compared to non-PSE ham. However, PSE meat could be mixed with normal meat for the production of fermented dry sausage without quality defects.     

Effects of Irradiation on Properties of Cured Ham

ABSTRACT: The quality characteristics of cured ham, treated with ionizing radiation (4.5 kGy) at different points in the curing process, were compared during a 90-d storage period. Irradiation treatments included irradiation of raw uncured ham, raw-cured ham, cured cooked ham, and a nonirradiated control. Irradiation processing increased lipid oxidation for all treatments. The raw-cured treatment resulted in significantly lower L* values compared with the control regardless of storage period. All treatments except for cured cooked ham had lower b* values over the storage period. Irradiation of cured cooked ham resulted in higher off-odor scores than all other treatments immediately following irradiation thus indicating a change in quality.     

UTILIZATION OF RESPONSE SURFACE MODELING TO EVALUATE THE EFFECTS OF NONMEAT ADJUNCTS AND COMBINATIONS OF PSE AND RFN PORK ON THE TEXTURE OF BONELESS CURED PORK

Combinations of pale, sop, and exudative (PSE) and red, firm. and nonexudative (RFN) semimembranosus muscle were utilized to manufacture chunked and formed, cured pork. Response Surface Methodology was utilized to investigate the effects of soy protein concentrate (SPC), sodium caseinate (SC), and modified food starch (MFS) on bind and texture profile analysis. Fifteen adjunct formulations for five PSE and RFN combinations provided 75 treatments for each of three replications. As CIE L* values of raw muscle increased, protein-protein bind decreased (P<0.05). MFS, SC, and SPC decreased (P<0.05) cohesiveness. MFS and SC decreased (P<0.05) chewiness, and MFS decreased (P<0.05) hardness. Utilizing these adjuncts demonstrated that MFS improved texture in PSE and RFN pork. This research demonstrated that diluting RFN pork with no more than 25% PSE pork permits the formation of a high quality boneless deli ham roll.     

Carcass characteristics and meat quality of halothane negative and halothane positive pietrain pigs

One hundred and seventy-six Pietrain pigs were tested for halothane sensitivity by means of a 5-min halothane anaesthesia in two experiments. One hundred and twenty were halothane negative (HN) and 56 were halothane positive (HP). In one experiment pigs were slaughtered under commercial (stress) conditions; in the other experiment pigs were killed under minimal stress conditions.

The carcasses of HP pigs were meatier and shorter and contained 2·2% more muscle than the carcasses of HN pigs.

Halothane positive pigs gave a meat of poorer quality, as assessed in the fresh state. When the pigs were slaughtered under commercial conditions, hams from HP pigs were not inferior in curing ability and had a higher total processing yield of Paris ham due to their higher trimming yield. When the pigs were killed under minimal stress conditions, there was no difference in the total processing yield betwen HN and HP pigs, because the technological yield was markedly reduced in HP pigs. However, in both cases, HP pigs produced more cooked ham per pig.

It is suggested that different physiological mechanisms may account for either PSE (pale soft exudative) or DFD (dark firm dry) meat. The former is the consequence of an excessively high rate of post mortem glycolysis which is clearly manifest in HP pigs when they are killed under minimal stress conditions and the latter appears to be unrelated to halothane sensitivity as the ultimate pH of HP and HN pigs is similar when the animals are slaughtered under stress conditions.     

High pressure effect on the color of minced cured restructured ham at different levels of drying, pH, and NaCl

Color changes of minced cured restructured ham was studied considering the effects of high pressure (HP) treatment (600 MPa, 13 °C, 5 min), raw meat pH₂₄ (low, normal, high), salt content (15, 30 g/kg), and drying (20%, 50% weight loss). Raw hams were selected based on pH₂₄ in Semimembranosus, mixed with additives, frozen, sliced, and dried using the Quick-Dry-Slice® process. Meat color (CIE 1976 L*a*b*) and reflectance spectra were measured before and after HP treatment. HP significantly increased L*, decreased a*, and decreased b* for restructured ham dried to 20% weight loss, regardless of salt content and pH₂₄. L* and a* were best preserved in high pH/high salt restructured ham. HP had no effect on the color of restructured ham dried to 50% weight loss. HP had no effect on the shape of reflectance curves, indicating that the pigment responsible for minced cured restructured ham color did not change due to HP.     

Zn-porphyrin formation in cured meat products: Effect of added salt and nitrite

Zn-porphyrin (Zn-pp) was quantified by fluorescence spectroscopy in the cured and dry cured meat products: Parma ham, Iberian ham, dry-cured ham with added nitrite, cooked ham with added nitrite, raw ham meat, raw bacon and Karree-Speck. The highest amount of Zn-pp was found in dry-cured Parma ham and Iberian ham, while the use of nitrite as curing agent was found to inhibit completely the formation of Zn-pp in meat products. A positive correlation between both Zn content and Fe content and the logarithmic transformed Zn-pp content (measured as fluorescence intensity I_fl) was found for the different cured and dry cured meat products, with correlation coefficients of 0.79 (p < 0.001) and 0.71 (p < 0.01), respectively. Log I_fl correlates best with the Zn content, indicating that the formation of Zn-pp is proportional to the Zn content. A model system with vacuum packed pork in brine with different added levels of sodium chloride with or without nitrite and Zn acetate was investigated in order to further elucidate the mechanism of Zn-pp formation. Zn-pp increased with time (up to 42 days investigated) in non-cured meat and for meat cured solely with NaCl lower than 9%. Addition of nitrite or Zn(II) in the curing brine was found to inhibit formation of Zn-pp confirming the observations from the various cured meat products. It is suggested that a chloride anion assisted dissociation of iron from myoglobin could be rate-determining for Zn-pp formation in meat products.     

The effect of using PSE meat in the manufacture of dry-cured ham

 Drying, salting, protein changes, colour and the sensory quality were studied in dry-cured ham manufactured from refrigerated and frozen/thawed raw pale, soft and exudative (PSE) meat. The results obtained showed that the use of PSE meat increases the level of drying, salting and proteolysis of the dry-cured ham, although it does not significantly affect the sensory quality. Freezing and thawing of the raw material accentuates the proteolytic and exudative nature of the meat during the curing process, and as a result the salting and drying levels increase to such an extent that the PSE effect in these hams is practically undetectable. Received: 6 June 1997 / Revised version: 17 July 1997     

Incidence of Listeria monocytogenes in different types of meat products on the Belgian retail market

A survey was undertaken to determine the incidence and numbers of L. monocytogenes in a variety of meat products (cooked meat products, raw cured meat products (dried or not), mayonnaise based salads and prepared meals). As expected, raw cured meat products were significantly higher contaminated with L. monocytogenes than cooked meat products, 13.71% (113/824) and 4.90% (167/3405), respectively. Also a larger proportion of raw cured meat product samples contained a high initial level of the pathogen ( > 10 cfu/g). Higher incidence rates were obtained for whole cooked meat products (e.g. cooked ham, bacon) after slicing than before slicing, 6.65 and 1.56%, respectively, indicating cross-contamination. Due to multiple handling and processing steps, the incidence rate of the pathogen was higher for cooked minced meat products than for whole cooked meat products, 6.14 and 3.96%, respectively. No significant differences were obtained in the incidence of L. monocytogenes in whole cured meat products (e.g., raw ham) and minced cured meat products (e.g., dry fermented sausage), 14.92 and 11.69%, respectively. Lower incidence rates of L. monocytogenes were obtained for raw, cured meat products using beef or horse meat, 4.65 and 5.88%, respectively, A high incidence rate of L. monocytogenes was noted for the mayonnaise based salads (21.28% (186/874)) as well as for prepared meals (11.70% (92/786)), the latter especially due to contamination of vegetarian meals.     

The influence of pre-slaughter oral loading of acid or base on post-mortem changes in Longissimus Dorsi muscle of pork

Twenty-four pigs were assigned to one of four ad libitum water treatments: control, sodium bicarbonate (12·6 g/litre), low ammonium chloride (4 g/litre) or high ammonium chloride (8 g/litre) for 5 days, to study the influence of an oral acid or base load on post-mortem changes in longissimus dorsi muscle and ultimate pork quality. Physiological changes before slaughter were monitored by measuring blood pH, pCO(2) and HCO(3)(-). The influence of dietary treatments on post-mortem changes and ultimate meat quality was determined by measuring glycolytic enzymes and intermediates, and muscle pH, color and water-holding capacity (WHC). As expected, sodium bicarbonate generated a metabolic alkalosis, whereas ammonium chloride resulted in a metabolic acidosis. Pre-slaughter acid-base status was positively correlated with muscle WHC (P < 0·05). However, no significant dietary treatment effect was observed in muscle quality traits such as color (a, b, L) and WHC. Muscle pH(45) was significantly (P < 0·05) higher in bicarbonate than control and high ammonium chloride treatments. The activity of Ca(2+)-dependent protein kinase was significantly (P < 0·05) higher at 45 min post-mortem but that of pyruvate kinase was significantly lower at 2 and 4 h post mortem in bicarbonate-treated pigs. At 45 min post mortem, the activity of fructose-1,6-diphosphatase in the control pigs was significantly higher (P < 0·05) than on other treatments. The concentration of glycogen was significantly (P < 0·05) higher in bicarbonate and high ammonium chloride pigs; bicarbonate-treated pigs also has significantly higher adenosine-5'-triphosphate (ATP) and pH values than other treatment groups (P < 0·05) at early post-mortem. It was concluded that pre-slaughter oral loading of acid or base could induce changes in muscle metabolism and post-mortem muscle pH. Further research is required to confirm that altering diet acidogenicity or alkalinogenicity may be a means of enhancing ultimate pork quality.     

Fibre optic probe measurements in landrace pigs of different halothane phenotypes

Fibre Optic Probe (FOP) measurements were made in the longissimus dorsi muscle of 70 halothane-positive (HP) and 70 halothane negative (HN) pigs of a synthetic Landrace strain at 45 min (FOP(1)), 3 h (FOP(3)) and 17h (FOP(17)) post mortem. Measurements of pH, rigor and temperature were also made in the slaughterline. Carcasses were sampled (longissimus dorsi, 2-4 lumbar vertebrae) at 18h post mortem and meat quality objectively assessed. The incidence of slight PSE (visual score) was 49% in HP and 10% in HN pigs, while the incidence of serious PSE was 20% and 4%, respectively. Yet, the percentage drip loss during 48 h storage in HN/PSE pigs was higher than in HP/PSE pigs (10·2 vs 7·5%), which was associated with a lower ultimate pH (5·25 vs 5·44). Therefore, it is suggested that the remaining PSE problem in HN Landrace pigs, although less in frequency, might be more serious. In the whole population, of all FOP measurements taken correlations with colour (Hunter L(?)-value) and percentage drip loss were highest for the FOP(17) measurements (r = 0·82 and 0·69, respectively). FOP(1) was better related than pH(1) to colour, while the relationships with drip loss were of a similar magnitude. Differences in FOP values between HP and HN pigs were larger for FOP(1) (148 vs 108) than for FOP(3) (148 vs 125) or FOP(17) (153 vs 130). The relationship between FOP1 and ultimate meat colour (L(?)-value) appeared to be higher in HP (0·60) than in HN (0·48) pigs, while for the relationship between FOP(1) and percentage drip loss the reverse was true (0·48 and 0·60, respectively). The effect of halothane phenotype on the relationships found, may partially explain the different results of reflectance measurements reported in the literature as to their predictive value for ultimate meat quality. The results suggest that the measurement of reflectance in the slaughterline offers opportunities for identifying (potential) PSE carcasses. The large genetic influence of halothane phenotype on this parameter, may eventually justify its use as a base for payment for meat quality to the producer.     

Effects of sodium lactate and other additives in a cooked ham product on sensory quality and development of a strain of Lactobacillus curvatus and Listeria monocytogenes.

Cooked cured ham products were produced according to a standard recipe for cooked ham with various levels of sodium lactate, sodium diacetate or buffered sodium citrate. They were compared with a reference ham product with respect to sensory quality and growth of Lactobacillus curvatus and Listeria monocytogenes. For this, a part of the products was sensory analysed directly after preparation. Another part of the cooked ham products was minced and homogeneously inoculated with L. curvatus (10(4)/g) and L. monocytogenes (10(2)/g) and filled in 60-g plastic pouches. After vacuum packaging, the pouches were stored at 4 degrees C for up to 40 days. Between the different ham compositions, only minor differences were found for appearance, internal colour, structure and firmness. The addition of 0.2% Na-diacetate had a negative effect on the odour and taste of the ham product. The addition of 2.5% to 3.3% Na-lactate inhibited the growth of L. curvatus compared to the reference, while 0.1% and 0.2% Na-diacetate did not. L. monocytogenes was best inhibited by the addition of Na-lactate but also by the addition of 0.2% Na-diacetate. On the other hand, the growth of L. monocytogenes was stimulated by the addition of 1% buffered Na-citrate.     

Pig sire type and sex effects on carcass traits,meat quality and physicochemical and sensory characteristics of Serrano dry‐cured ham

This study demonstrates that improvements in animal line selection by breeding enterprises exert a strong effect on carcass traits, meat quality and sensory characteristics of Serrano dry‐cured ham. A total of 461 pigs from the offspring of a Duroc (DU) × Landrace (LD) sow mated with two DU boars and a DU × Large White (LW) boar from three breeding enterprises were evaluated. The two DU terminal sires were significantly different (P < 0.05) in carcass conformation, backfat thickness, ham and loin yields, raw ham traits, myoglobin concentration and total pigments formed during the curing process; in addition, the two lines provided different percentages of hams (54 vs 91%) with sufficient subcutaneous fat and weight to manufacture dry‐cured Serrano hams using a slow ripening process (11 months). The DU × LW sire had the best carcass and ham traits from an economic standpoint and obtained highest scores for sensory characteristics of Serrano ham evaluated by a trained panel test; furthermore, this line provided 84% of total hams suitable for manufacturing Serrano hams by a slow process. When the sex effect was analysed, carcass and ham traits of females were more favourable, but females presented a higher incidence of pale, soft and exudative (PSE) meat and a lower percentage of hams with sufficient subcutaneous fat and weight to produce Serrano hams using a slow ripening process (61% for females and 91% for castrates). On the other hand, castrates provided Serrano hams cured by a slow procedure with better organoleptic characteristics than females. Right and left hams were similar. Copyright © 2005 Society of Chemical Industry     

Utilization of response surface modeling to evaluate the effects of non-meat adjuncts and combinations of PSE and RFN pork on water holding capacity and cooked color in the production of boneless cured pork

Boneless cured pork was produced from combinations of pale, soft, and exudative (PSE) and red, firm, and non-exudative (RFN) semimembranosus muscle. Response Surface Methodology was utilized to determine the effects of soy protein concentrate (SPC), sodium caseinate (SC), and modified food starch (MFS) on the water holding capacity and cooked color in a chunked and formed product. Fifteen ingredient combinations were replicated three times for each PSE and RFN combination giving 75 treatments per replication. Utilization of SPC decreased (P<0.01) cooking loss and redness while increasing (P<0.01) yellowness. MFS decreased (P<0.01) expressible moisture, and both MFS and SC increased (P<0.05) cooked redness while decreasing (P<0.01) cooked lightness. Product formulations using these adjuncts demonstrate potential to improve the water-holding capacity and cooked color in PSE as well as RFN pork. This research also demonstrated that diluting RFN pork with no more than 25% PSE pork permits the formation of a high quality boneless deli ham roll.     

钠盐替代物对西式火腿品质的影响

通过肉汤模拟得出西式火腿中各替代盐的最大添加比例,并根据比例制作对照组、低钠盐组、氯化钾组、氯化钙组、乳酸钾组西式火腿,研究不同替代盐对西式火腿品质的影响。结果表明：通过模拟肉汤的感官评价,确定各替代盐的最适添加比例分别为氯化钾30%、氯化钙25%、乳酸钾35%;不同替代盐会对西式火腿的水分含量、汁液流失、质构及感官评分等造成显著差异（P＜0.05）,但并不会造成明显的色泽变化;其中低钠盐组西式火腿的综合品质最差,具体表现为水分含量最低（59.8%）、硬度最高（3 704 g）及口感得分最低（7.8 分）等,而乳酸钾相比低盐钠组品质仅有略微提升;氯化钾组和对照组西式火腿品质最为相似,感官评分、水分含量及质构等均无显著差异;氯化钙组西式火腿品质最好,表现为蒸煮损失最低（6.51%）及感官得分最高（9.1 分）等。因此,从最大钠盐替代量方面考虑,30%氯化钾组最为适合,而从提升西式火腿品质方面考虑,25%氯化钙组更为适合。     

Pre-cure freezing affects proteolysis in dry-cured hams

Several parameters (sodium chloride, moisture, intramuscular fat, total nitrogen, non-protein nitrogen, white precipitates, free tyrosine, L* a* b* values and acceptability) related with proteolysis during the curing were compared in dry-cured hams manufactured from refrigerated and frozen/thawed raw material. Pre-cure freezing increased the proteolysis levels significantly (p<0.05) in the zones of the ham where water losses and absorption of salt is slowest. Frozen hams present a high incidence of white precipitates, formed mainly by tyrosine crystals. The colour and acceptability scores are similar in frozen and refrigerated hams. The previous freezing and thawing process accentuates the water losses, salt absorption and proteolysis of the cured meat, although it does not significantly affect the sensory quality of the dry-cured ham.     

THE STUDY OF INGREDIENTS AND PROCESSING TECHNIQUES OF XUANWEI STYLE HAM

Xuanwei style ham is one of the famous dry-cured hams in the world. The influences of different ingredients and processing techniques on sensory properties, brine diffusing rate, chemical composition and hygienic quality of Xuanwei style cured ham were studied. Modified cured ham processing techniques were employed in this study. Massaging of green ham and injection of curing solution improved brine diffusing rate ( P <  0.05) and reduced curing time from the traditional 28 days to 21 days (weight of green ham about 13 kg). Ninety mg/kg sodium nitrite was used for improving cured ham color ( P <  0.05), and its residue still met the Chinese cured ham standard of 20 mg/kg. The hygienic and sensory qualities were not significantly affected by the addition of sodium ascorbate and polyphosphate ( P >  0.05).

PRACTICAL APPLICATIONS

The paper studied the Chinese famous Xuanwei dry-cured ham, modified curing ingredient and processing techniques of Xuanwei ham are beneficial for improving the ham quality and important to shorten the traditional cured ham processing procedure such as longer processing time and seasonal processing method to adapt to the new industrial procedures of manufacturing and marketing of Xuanwei cured ham.     

宣威火腿加工过程中的理化变化与标准化生产技术

应用现代肉制品腌制技术,对宣威火腿进行标准化腌制,能够稳定产品质量,避免腌制失败的风险。在宣威市的自然气候条件下进行干燥成熟,火腿表层肌肉(半膜肌)中的水分、食盐和游离氨基酸含量均低于深层肌肉(股二头肌),终产品中这些指标的含量分别为:43.93%和55.25%;8.80%和11.14%;5425.02mg/100g(DM)和9040.45mg/100g(DM),表现出明显的部位差异,达不到标准化产品的质量要求。根据试验结果和资料分析提出的宣威火腿标准化、周年化生产工艺条件,将对生产原料的质量及加工过程中发生的理化及生物学变化进行控制,以便稳定产品质量,保持产品风味的一致性。     

Benchmarking value in the pork supply chain: Processing and consumer characteristics of hams manufactured from different quality raw materials

Impact of fresh ham quality on finished ham product characteristics was evaluated. Bone-in hams destined for spiral-sliced ham manufacturing were sorted into two pH groups before processing: pH ⩽ 5.5 and pH ⩾ 5.6. For boneless hams, raw materials were sorted into groups with different levels of pale, soft, and exudative (PSE) product before manufacturing into sliced vacuum packaged hams: “Low PSE” (⩽5% PSE muscle), “Intermediate PSE” (20–30% PSE muscle) or “High PSE” (40–60% PSE muscle). Few differences were observed between the pH ⩽ 5.5 and pH ⩾ 5.6 groups in objective color measures and drip loss in bone-in spiral-sliced hams stored under refrigeration, however, after frozen storage, hams from the pH ⩽ 5.5 group had lower L*- and a*-values and had much higher drip loss than those from the pH ⩾ 5.6 group. Processing yields for bone-in spiral-sliced hams were similar through cooking and chilling, however, the pH ⩾ 5.6 group had higher yields after slicing. For boneless hams, defects occurred at a greater frequency in hams formulated with a greater percentage of PSE raw materials than those with lower amounts of PSE. Differences in objective color measures and purge were minimal over the duration of storage time, but hams formulated with greater percentages of PSE raw materials were lighter in appearance and had less redness. Consumers gave lower color responses for hams formulated with “High PSE” amounts, but did not differentiate between hams manufactured with lower quantities of PSE muscle. However, when consumers directly compared packages of ham, there was distinct discrimination against hams manufactured with greater amounts of PSE. Purchase intent showed that consumers favored ham manufactured from fresh ham muscles containing low quantities of PSE tissue. Further research is needed to determine the optimal ratio of allowable PSE product in formulation that enables processors to maximize consumer appeal with the economic realities of sorting out PSE pork.     

Effect of Hops Beta Acids on the Survival of Unstressed‐ or Acid‐Stress‐Adapted‐Listeria Monocytogenes and on the Quality and Sensory Attributes of Commercially Cured Ham Slices

This study evaluated the antilisterial activity of hops beta acids (HBA) and their impact on the quality and sensory attributes of ham. Commercially cured ham slices were inoculated with unstressed‐ and acid‐stress‐adapted (ASA)‐L. monocytogenes (2.2 to 2.5 log CFU/cm²), followed by no dipping (control), dipping in deionized (DI) water, or dipping in a 0.11% HBA solution. This was followed by vacuum or aerobic packaging and storage (7.2 °C, 35 or 20 d). Samples were taken periodically during storage to check for pH changes and analyze the microbial populations. Color measurements were obtained by dipping noninoculated ham slices in a 0.11% HBA solution, followed by vacuum packaging and storage (4.0 °C, 42 d). Sensory evaluations were performed on ham slices treated with 0.05% to 0.23% HBA solutions, followed by vacuum packaging and storage (4.0 °C, 30 d). HBA caused immediate reductions of 1.2 to 1.5 log CFU/cm² (P < 0.05) in unstressed‐ and ASA‐L. monocytogenes populations on ham slices. During storage, the unstressed‐L. monocytogenes populations on HBA‐treated samples were 0.5 to 2.0 log CFU/cm² lower (P < 0.05) than control samples and those dipped in DI water. The lag‐phase of the unstressed‐L. monocytogenes population was extended from 3.396 to 7.125 d (control) to 7.194 to 10.920 d in the HBA‐treated samples. However, the ASA‐L. monocytogenes population showed resistance to HBA because they had a higher growth rate than control samples and had similar growth variables to DI water‐treated samples during storage. Dipping in HBA solution did not adversely affect the color or sensory attributes of the ham slices stored in vacuum packages. These results are useful for helping ready‐to‐eat meat processors develop operational procedures for applying HBA on ham slices.     

High pressure treatments on the inactivation of Salmonella Enteritidis and the physicochemical, rheological and color characteristics of sliced vacuum-packaged dry-cured ham

The effect of high pressure (HP) on Salmonella Enteritidis in sliced dry-cured ham stored under temperature abuse (8°C) during 60d was investigated. After treatment, reductions of S. Enteritidis were 1.06, 2.54 and 4.32 log units in ham treated at 400, 500 and 600MPa for 5min at 12°C, compared to non-pressurized samples. After 60d, counts of S. Enteritidis in ham treated at 400 and 500MPa were 2.56 and 2.66 log units lower than in non-treated ham, whereas the pathogen was only detected after enrichment in ham treated at 600MPa. Lipid oxidation increased with storage and pressurization, whereas total free amino acid contents were similar in HP and control samples after 60d. Dry-cured ham treated at the highest pressures exhibited lower shear resistance, whereas the maximum force to compress the sample was slightly changed. Color (L*, a* and b*) varied with pressurization and storage. Changes induced by HP in dry-cured ham were attenuated during storage.