Dry-cured Meat Products Research Articles

Inhibition of ochratoxigenic moulds by Debaryomyces hansenii strains for biopreservation of dry-cured meat products

The ability of the osmotolerant yeast Debaryomyces hansenii to inhibit Penicillium nordicum, the most common ochratoxigenic mould encountered in dry-cured meat products, was evaluated. The antagonistic effect of ten D. hansenii strains isolated from dry-cured ham was screened in vitro using malt extract media and meat extract peptone media with the water activity (aw) adjusted to 0.97 and 0.90. A significant inhibition of the two tested P. nordicum strains by D. hansenii cells and cell-free supernatants was observed. At 0.97 aw, increasing D. hansenii inoculum concentrations significantly improved the inhibition of mould growth on solid medium, whereas at 0.90 aw this was not always the case. As observed by bright field microscopy, most D. hansenii strains were able to delay P. nordicum spore germination when co-cultured in malt extract broth. D. hansenii FHSCC 253H showed the highest overall in vitro inhibition of ochratoxigenic mould growth, and was therefore chosen for co-cultivation assays in dry-cured ham slices incubated at 0.94 and 0.84 aw simulating ham ripening. Regardless of the experimental conditions tested, lower levels of the inoculated P. nordicum strain were detected in co-cultivation batches compared with batches without D. hansenii. The highest level of mould growth inhibition was observed in batches at 0.94 aw. Ochratoxin A (OTA) production in ham samples was detected by HPLC-MS. Co-culturing of P. nordicum with D. hansenii FHSCC 253H resulted in lower OTA levels compared with control samples without D. hansenii. The decrease of the mycotoxin presence due to D. hansenii FHSCC 253H was more efficient at 0.94 aw (OTA was below the detection limit). In conclusion, D. hansenii is potentially suitable as a biopreservative agent for preventing ochratoxigenic mould growth and OTA accumulation in dry-cured meat products. The inoculation of D. hansenii should be made at the beginning of processing (at the end of post salting) when the aw of the product is still high (near 0.94). This action in addition to application of appropriate hygienic actions and control of temperature and relative humidity throughout ripening is required to reduce health risks due to OTA exposure.

Ochratoxin A in traditional dry-cured meat products produced from sub-chronic-exposed pigs

The presence of ochratoxin A (OTA) was determined in traditional dry-cured meat products made from sub-chronically OTA-exposed pigs. The experimental group of pigs (n = 5) was treated with 300 µg OTA kg–1 of feed during 30 days, whereas the control group (n = 5) remained untreated. After the household production of six types of dry-cured meat products based on traditional recipes, OTA residues were determined in final products produced from each treated and untreated animal using an immunoenzymatic technique (ELISA) and HPLC with fluorescence detection (HPLC-FD). The analytical methods showed acceptable analytical performance results and high correlation coefficients. Mean OTA concentrations ranged from 4.51 ± 0.11 µg kg–1 in smoked ham to 6.87 ± 2.01 µg kg–1 in home-made Slavonian sausage. The study demonstrated that pig exposure to OTA leads to the accumulation of OTA residues in muscle and adipose tissue used for the production, and consequently results in contamination of the final meat products.

Advances in the ultrasound characterization of dry-cured meat products

In this work, the feasibility of using non-contact ultrasonic techniques (air-coupled and scanning acoustic microscopy, SAM) for characterizing different dry-cured meat products was assessed. Air-coupled ultrasonic measurements were performed on vacuum packaged sliced dry-cured ham, and compared with contact measurements. The average ultrasonic velocity in dry-cured ham was 1846±49m/s and 1842±42m/s for air-coupled and contact measurements, respectively. The deviation (1% relative error) between both techniques was related to the influence of the heterogeneous structure and composition of dry-cured ham and the transducer focusing. The SAM was used to characterize dry-cured ham and chorizo samples. B-scan images for dry-cured ham and chorizo showed two dominant reflections from the sample, linked to reflections in the lean and fatty tissues. The results indicate that contact ultrasonic measurements could be replaced by the air-coupled technique, reducing the measuring time and the material handling. On the other hand, SAM technique allows the microscopic characterization of dry-cured meat products.

A correlative study on data from pork carcass and processed meat (Bauernspeck) for automatic estimation of chemical parameters by means of near-infrared spectroscopy

The use of near-infrared spectroscopy (NIRS) is proposed in this study for the characterization of the quality parameters of a smoked and dry-cured meat product known as Bauernspeck (originally from Northern Italy), as well as of some technological traits of the pork carcass used for its manufacturing. In particular, NIRS is shown to successfully estimate several key quality parameters (including water activity, moisture, dry matter, ash and protein content), suggesting its suitability for real time application in replacement of expensive and time consuming chemical analysis. Furthermore, a correlative approach based on canonical correlation analysis was used to investigate the spectral regions that are mostly correlated to the characteristics of interest. The identification of these regions, which can be linked to the absorbance of the main functional chemical groups, is intended to provide a better understanding of the chemical structure of the substrate under investigation.

Ultrasonic characterization of the fat source and composition of formulated dry-cured meat products

The aim of this work was to test the feasibility of using ultrasonic measurements to estimate the fat content and identify the fat sources used in formulated dry-cured pork meat products. For that purpose, dry-cured sausages were prepared using different fat sources (two Iberian pork backfats, Iberian lard, and sunflower oil) and contents (fat content from 3% to 17% wet basis) and characterized by measuring the ultrasonic velocity (at 2 degrees C, 6 degrees C, 10 degrees C, 15 degrees C, 20 degrees C, and 25 degrees C), fatty acid profile, thermal behavior, and composition. The fatty acid composition affected the melting behavior of the sausages, which also involved different ultrasonic velocities, depending on the fat source used for the sausage formulation. Significant (p < 0.05) linear relationships were established between the ultrasonic velocity and the percentage of melted fat, by means of which the sausage batches were differentiated according to the fat source used. The ultrasonic velocity temperature dependence allowed the determination of the fat content (explained variance 96.1%) by measuring the ultrasonic velocity in the dry-cured sausages at 2 degrees C and 25 degrees C and using a semi-empirical equation. Therefore, the ultrasonic measurements could be considered as a reliable tool for the characterization and differentiation of formulated dry-cured meat products with different fat sources and contents.

Effect of tiger nut fibre addition on the quality and safety of a dry-cured pork sausage (“Chorizo”) during the dry-curing process

There is a growing interest in the revalorization of co-products from the food industry. Co-products from tiger nuts (Cyperus esculentus) milk production are a suitable fibre source. “Chorizo” is the most popular dry-cured meat product in Spain. The aim of this work was to study the effect of the tiger nut fibre addition (0, 5, and 7.5%) on the quality (composition, physicochemical, and sensorial properties) and safety (oxidation and microbial quality) of a Spanish dry-cured sausage, during the 28days of its dry-curing process. Tiger nut fibre (TNF) addition decreased fat and increased moisture content. The addition of TNF significantly increased (p<0.05) the total dietary fibre content of “Chorizo”. Lightness (L*), yellowness (b*) and redness index (a*/b*) were significantly (p<0.05) affected by the fibre content. The addition of 5% and 7.5% TNF to chorizo provided rich fibre and a healthier product. Although there were slight changes in the physicochemical properties, its quality (traditional characteristics) and its safety remained.

Natural occurrence of aflatoxin B1, ochratoxin A and citrinin in Croatian fermented meat products

When domestic animals are exposed to mycotoxins, significant amounts of the latter shall be carried over into animal products such as milk, eggs and meat. This study was carried out in order to determine the possible presence of aflatoxin B1 (AFB1), ochratoxin A (OTA) and citrinin (CIT) in game sausages (n = 15), semi-dry sausages (n = 25) and fermented dry-meat products (n = 50), randomly taken from individual producers and the Croatian market. AFB1 and OTA were quantified using ELISA, while CIT was quantified using HPLC-fluorescence detector. Out of 90 samples, the fungi most frequently isolated from dry-cured meat products were of Penicillium species, while Aspergillus was isolated from only one sample. As much as 68.88% of the samples were positive for mycotoxins. Finally, the analysis of different types of meat products resulted in OTA identification in 64.44%, CIT identification in 4.44% and AFB1 identification in 10% of the samples. The maximum OTA concentrations established in the commercial sausage samples equalled to 7.83 μg/kg, while that of AFB1 amounted to 3.0 μg/kg. Generally, although OTA was detected in all three types of products in different percentage shares, mutual differences were not statistically significant (P > 0.05).

Sucuk and pastırma: Microbiological changes and formation of volatile compounds

There is an increasing interest in traditional foods in Turkey like other countries. Sucuk, dry-fermented sausage, and pastırma, a type of dry-cured meat product, are traditional Turkish meat products that are widely consumed. Sucuk is air-dried and neither smoked nor ripened by mold. In spite of increasing use of starter culture in production of sucuk in the industry, traditionally produced sucuk is generally preferred by the consumers because of its sensory characteristics. Pastırma is traditionally processed under natural conditions where air temperature and relative humidity depend on climate and weather conditions. Pastırma differs from other raw cured meat products made from whole pieces of meat in terms of manufacturing process, ingredients, microbial properties and flavor. In this study, microbiological changes and formation of volatile compounds in sucuk and pastırma were reviewed.

Use of pulsed light to increase the safety of ready-to-eat cured meat products

Pulsed light (PL) was tested for its efficacy to reduce Listeria monocytogenes and Salmonella enterica serovar Typhimurium on the surface of two ready-to-eat (RTE) dry cured meat products (salchichón and loin). Maximum log reductions between 1.5 and 1.8 cfu/cm2 were obtained for both microorganisms when a fluence of 11.9 J/cm2 was applied. Slight and particular differences in the instrumental color parameters were observed due to the treatment in both products, although no changes in the sensory analysis were detected either immediately after treatment or during 30 days storage in salchichón. Panelists perceived some changes in the sensory quality of loin immediately after treatment, but these differences disappeared along storage. PL could be considered a useful alternative to other non-thermal techniques for increasing the safety of RTE dry cured meat products.

Perplexing cases of allergy to salami

Perplexing cases of allergy to salami

Ultrasonic characterization of pork meat salting

Salting process plays a key role in the preservation and quality of dry-cured meat products. Therefore, an adequate monitoring of salt content during salting is necessary to reach high quality products. Thus, the main objective of this work was to test the ability of low intensity ultrasound to monitor the salting process of pork meat. Cylindrical samples (diameter 36 mm, height 60±10 mm) of Biceps femoris were salted (brine 20% NaCl, w/w) at 2 °C for 1, 2, 4 and 7 days. During salting and at each experimental time, three cylinders were taken in order to measure the ultrasonic velocity at 2 °C. Afterwards, the cylinders were split in three sections (height 20 mm), measuring again the ultrasonic velocity and determining the salt and the moisture content by AOAC standards. In the whole cylinders, moisture content was reduced from 763 (g/kg sample) in fresh samples to 723 (g/kg sample) in samples salted for 7 days, while the maximum salt gain was 37.3 (g/kg sample). Although, moisture and salt contents up to 673 and 118 (g/kg sample) were reached in the sections of meat cylinders, respectively. During salting, the ultrasonic velocity increased due to salt gain and water loss. Thus, significant (p<0.05) linear relationships were found between the ultrasonic velocity and the salt (R2 = 0.975) and moisture (R2 = 0.863) contents. In addition, the change of the ultrasonic velocity with the increase of the salt content showed a good agreement with the Kinsler equation. Therefore, low intensity ultrasound emerges as a potential technique to monitor, in a non destructive way, the meat salting processes carried out in the food industry.

Characterization of coagulase-negative staphylococci isolated from Spanish dry cured meat products

Technological and safety-related properties were analyzed in a coagulase-negative staphylococci (CNS) collection isolated from Spanish dry-cured meat products in order to use them as starter cultures. The highest nitrate reductase and proteolytic activity was showed by Staphylococcus carnosus and Staphylococcus equorum. Only a few strains were able to form biofilms and the presence of the ica gene was analyzed on them. In relation to antibiotic resistance, all S. carnosus and most of the S. equorum strains were sensitive to the antibiotics tested and the presence of the blaZ gene in the β-lactamic resistant strains was studied. Biogenic amines were produced by 25% of the strains analyzed being all the S. carnosus strains tyramine producers. Taking into account the studied properties, two S. equorum strains could be selected as adequate and safe potential starter cultures for the elaboration of meat products.

High pressure processing of dry-cured ham: Ultrastructural and molecular changes affecting sodium and water dynamics

Abstract High pressure processing (HPP) has become a popular method to reduce bacterial load on dry-cured ham. However, HPP processed hams tend to present higher saltiness than non-processed ones. In this study was evaluated the effect of processing biceps femoris samples of 9 dry-cured hams aged for 15 months at a pressure of 0.1, 300, 600 and 900 MPa. 23Na-Nuclear Magnetic Resonance (NMR) relaxation values were used to determine the mobility of sodium. Ultrastructure changes at 600 MPa were evaluated by transmission electron microscopy (TEM) analysis. Double quantum NMR experiments demonstrated that pressure promoted tighter binding of bound sodium to proteins. However, a small proportion of sodium was liberated. The modification of myofibril ultrastructure at 600 MPa observed by TEM and the denaturation observed between 300 and 600 MPa facilitate the liberation of a proportion of sodium. That together with the decrease of water holding capacity between unpressurised and 900 MPa samples makes sodium more noticeable for saltiness perception, which could be of interest for sodium reduced dry-cured meat products. Industrial relevance High pressure processing of cured ham is a non-thermal pasteurization actually used in Spain. Even if the technology answer the microbiological goals to control microorganisms, an increase of saltiness perception have been detected. The understanding of this phenomenon from an ultrastructural and molecular perspective could help to present high pressure processing treatments as an alternative solution for salt reduction in dry-cured meat products in order to obtain healthier food products and good consumer acceptance.

The impact of fast drying (QDS process®) and high pressure on food safety of NaCl-free processed dry fermented sausages

In the present study the food safety impact of the QDS process® combined with a high pressure treatment at 600 MPa was evaluated in NaCl-free processed acid (pH 4.8) and low-acid (pH 5.2) chorizo. A challenge test was performed where the raw meat batter was spiked with low levels of Listeria monocytogenes and Salmonella (< 100 CFU/g) and chorizos were manufactured following either a traditional drying or a QDS process®. After drying, half of the sliced chorizo samples were pressurized (600 MPa, 5 min, 13 °C) and stored under refrigeration for 91 days. QDS processing proved to be adequate for the production of safe NaCl-free processed dry fermented sausages. Regarding pathogenic microorganisms elimination, it was as effective as traditional processing for acid chorizo and even safer for low-acid chorizo. The high pressure treatment assured absence of both pathogens in all samples during the whole storage time. Sausage reformulation to meet NaCl-free processing requirements modified the progress of pH and technological microbiota. Industrial relevance: The QDS process® was designed to reduce the manufacturing time of sliced dry-cured meat products. It allows a just in time workflow, requires less space and energy and facilitates the rapid elaboration of new products, implying fast adaptation to marketing promotions. Among them, dry fermented sausages with reduced sodium chloride content is currently one of the major subjects investigated on the meat sector. Reduction of NaCl and the use of replacers, however, could negatively affect food safety and quality, which must therefore be properly evaluated. To extend shelf-life and improve safety, especially in products which are reformulated, high pressure processing could be a useful technology. The development of safe NaCl-free sliced dry fermented sausages in a short period of time is relevant for industry to meet consumer demands for convenient and healthy ready-to-eat products.

Biogenic amines content during extended ageing of dry-cured pork loins inoculated with probiotics

The study determined the content of biogenic amines in dry-cured pork loins inoculated with Lactobacillus casei ŁOCK 0900 probiotic strain, in 4, 8 and 16month-old samples. Cadaverine, putrescine and tryptamine levels showed a time-dependent increase during ageing. Histamine and spermidine were not detected. Spermine which was present at very low concentrations, tended to decrease. Cadaverine and tryptamine were the main biogenic amines at the end of the ageing period with average values of 39.6mg/kg and 49.2mg/kg respectively. The results were within the values reported for other dry-cured meat products and below the suggested toxic levels. The pH of samples increased significantly (p<0.05) with ageing time. The aw values decreased significantly (p<0.05) during ageing, with a mean value of 0.953±0.007 for samples aged for 4months, and 0.852±0.007 for samples aged for 16-months.

Design of a method to evaluate yeasts to be used as starter cultures in dry-cured meat products

Some yeasts are involved in flavour development of dry-cured meat products showing a positive impact on the generation of volatile compounds. The aim of this work was to design a method of routine analysis to evaluate the production of volatile compounds by yeasts to be selected as starter cultures. For this purpose, several variations of a minimum culture medium that included free amino acids, oleic acid, and &amp;alpha;-ketoglutarate, incubated under similar conditions of water activity and pH as dry-cured meat products, were assayed. In these conditions, the representative yeast strains isolated from a dry-cured meat product were tested. The volatile compounds were analysed using Solid Phase Micro-Extraction and gas chromatography/mass spectrometry. In the designed media, the tested yeasts produced volatile compounds involved in flavour development of dry-cured meat products. In addition, all the strains showed the highest production of these volatile compounds in the complete minimum culture medium witch included &amp;alpha;-ketoglutarate and oleic acid.

Characterization of lactic acid bacteria from Turkish Pastirma

A total of 92 lactic acid bacteria (LAB) isolated from Turkish Pastirma (a salted and dry-cured meat product) were identified by means of phenotypic characteristics. Of these, 45 exhibited a different phenotypic characteristic selected as representative and identified by automated ribotyping. The phenotypic characterization of predominant LAB isolated from the traditional manufactured Pastirma was based on general morphology, physiological tests and API system. The genotypic characterization of LAB was determined with automated EcoRI ribotyping. Identification made according to phenotypic and biochemical characteristics shows the isolates were LAB and that nine different bacterial groups could be distinguished. Lactobacillus plantarum was the main species detected. In addition, Lactobacillus sakei, Enterococcus faecium and Pediococcus acidilactici species were obtained by automated ribotyping. A few strains were phenotypically misidentified as Lactobacillus fermentum or L. pentosus, while the phenotypic characteristics were resolved in L. sakei and Weissella confusa by ribotyping. Ribotyping shows a good correlation with phenotypic methods except 4 clusters.

Proteolytic activity of lactic acid bacteria strains and fungal biota for potential use as starter cultures in dry-cured ham.

During the processing of dry-cured meat products, sarcoplasmic and myofibrillar proteins undergo proteolysis, which has a marked effect on product flavor. Microbial proteolytic activity is due to the action of mostly lactic acid bacteria (LAB) and to a lesser extent micrococci. The proteolytic capacity of molds in various meat products is of interest to meat processors in the Mediterranean area. Eleven LAB and mold strains from different commercial origins were tested for proteolytic activity against pork myosin, with a view to possible use of these strains as starter cultures for Iberian dry-cured ham. Proteolytic activity was tested by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The LAB strains with the highest proteolytic activity were Lactobacillus plantarum (L115), Pediococcus pentosaceus (Saga P TM), and Lactobacillus acidophilus (FARGO 606 TM). The best fungal candidate was Penicillium nalgiovense LEM 50I followed by Penicillium digitatum, Debaryomyces hansenii, and Penicillium chrysogenum.

Physicochemical and nutritional composition of dry-cured duck breast

A total of 80 dry-cured duck breasts were used in this study. The gross composition, color and textural parameters, fatty acid and amino acid profiles, macro- and micromineral content, and sensory properties were analyzed. In comparison with other dry-cured meat products made from cuts of whole meat, dry-cured duck breast is characterized by low moisture and a higher protein content. Saturated, monounsaturated, and polyunsaturated fatty acid contents in intramuscular fat were approximately 35, 57, and 8% of the total fatty acid methyl esters, respectively. The main essential amino acids present in dry-cured duck breast were lysine and leucine, followed by valine, threonine, and isoleucine, with aspartic and glutamic acids being the most important in the nonessential fraction. Dry-cured duck breast proved to be a valuable source of iron, zinc, copper, and manganese (7.57, 4.66, 0.84, and 0.87 mg/100 g of edible portion, respectively), providing approximately 57, 45.2, 93, and 43.7% of the recommended daily allowances, respectively.

Lipolysis, proteolysis and sensory characteristics of a Spanish fermented dry-cured meat product (salchichón) with oregano essential oil used as surface mold inhibitor

The superficial antifungal activity of oregano essential oil (OEO) in Spanish fermented dry-cured sausages (“salchichón”), and its effects on lipolysis, proteolysis and sensory characteristics were evaluated. The surface application of OEO reduced mold contamination on the surface, without significantly affecting the drying process. To evaluate the intensity of lipolysis during the ripening process, the profile and content of free fatty acids were determined. The addition of OEO led to a higher amount of unsaturated fatty acids, but lipolysis was not greatly affected. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which was used to qualitatively assess the proteolytic changes in the sarcoplasmic and myofibrillar proteins during the process, pointed to very similar patterns in all the sausages. OEO did not significantly affect the sensory properties, but increased hardness, resulting in a better texture. Therefore, a shorter ripening time may be necessary for sausages treated with OEO.