Microbiological, Biochemical and Textural Characteristics of a Tunisian Dry Fermented Poultry Meat Sausage Inoculated With Selected Starter Cultures

The effects of Lactiplantibacillus plantarum 3-19 and Pediococcus pentosaceus 18-1 on preventing the accumulation of biogenic amines and promoting the production of volatile organic compounds during sour meat fermentation

Lactic acid bacteria (LAB) are frequently used in meat fermentation, and mixed stater cultures are reported to perform better than single ones. Lactiplantibacillus plantarum 3-19 and Pediococcus pentosaceus 18-1 were chosen from 28 sour-meat-origin strains to examine the effects of single and combined inoculation on sour meat quality. Natural fermentation was used as a control to investigate changes in pH, water activity (aw), amino acid nitrogen (AN), texture, microbial diversity, and volatile organic compounds (VOCs) during fermentation. The pH and aw of each inoculation group were significantly decreased, and AN content was significantly increased. The inoculation of P. pentosaceus 18-1 significantly reduced putrescine, cadaverine, and tryptamine content (p < 0.05), while the inoculation of Lpb. plantarum 3-19 significantly reduced cadaverine amounts (p < 0.05). At the fermentation endpoint, the total biogenic amines content in the C group was 992.96 ± 14.07, which was 1.65, 2.57, and 3.07 times higher than that in the Lp, Pe, and M groups, respectively. The mixed inoculation group combined the advantages of both strains and decreased total biogenic amines most significantly. At the end of fermentation, the VOCs in C, Lp, Pe, and M groups were 10.11, 11.56, 12.45, and 13.39 times higher than those at the beginning of fermentation. Inoculation promoted the production of key VOCs (OAV > 2000) such as heptanal, octanal, and (E)-2-nonanal. The mixed inoculation group had the highest variety and content of VOCs and the highest content of the above key VOCs, significantly enhancing its fruity, floral, ester, and other aromas. Sensory evaluation indicated that the M group had the best overall acceptability. Finally, it was suggested that a combination of Lpb. plantarum 3-19 and P. pentosaceus 18-1 is a novel and efficient starter culture for processing sour meat since they lower the amounts of biogenic amines in the meat and promote the production of VOCs.

Effect of Limosilactobacillus fermentum 332 on physicochemical characteristics, volatile flavor components, and Quorum sensing in fermented sausage

The effects of Limosilactobacillus fermentum 332 on quality characteristics in fermented sausage were explored in terms of physicochemical characteristics, volatile flavor components, and Quorum sensing (QS). The results showed that the pH of fermented sausage decreased from 5.20 to 4.54 within 24 h with the inoculation of L. fermentum 332. Lightness and redness were significantly improved, and hardness and chewiness were significantly increased after the addition of L. fermentum 332. With the inoculation of L. fermentum 332, the thiobarbituric acid reactive substance content decreased from 0.26 to 0.19 mg/100 g and total volatile basic nitrogen content decreased from 2.16 to 1.61 mg/100 g. In total, 95 and 104 types of volatile flavor components were detected in the control and fermented sausage inoculated with starter culture, respectively. The AI-2 activity of fermented sausage inoculated with L. fermentum 332 was significantly higher than that of the control and positively correlated with viable count and quality characteristics. These results provide support for further research on the effect of microorganisms on the quality of fermented food.

Effect of a Selected Protective Culture of Lactilactobacillus sakei on the Evolution of Volatile Compounds and on the Final Sensorial Characteristics of Traditional Dry-Cured Fermented "Salchichón"

BACKGROUND

In this work, the effect of a selected starter culture of Lactilactobacillus sakei 205 on the evolution of volatile compounds throughout the ripening process and on the final sensorial characteristics of traditional dry-cured fermented "salchichón" was evaluated.

METHODS

"Salchichón" sausages were prepared, inoculated with L. sakei 205, and ripened for 90 days. Volatile compounds were analyzed throughout the ripening by GC-MS. In the final product, instrumental texture and color were determined. In addition, sensorial analysis was performed by a semi-trained panel.

RESULTS

The inoculation of L. sakei 205 does not influence the texture and color parameters of ripened "salchichón". However, an increase in volatile compounds derived from amino acid catabolism and microbial esterification and a decrease in compounds derived from lipid oxidation, mainly hexanal, were observed throughout the ripening time as a consequence of L. sakei inoculation, which could have a positive effect on the flavor development of the dry-cured fermented "salchichón".

CONCLUSIONS

The use of selected strains of lactic acid bacteria (LAB) such as L. sakei 205 as a protective culture could be recommended to improve the quality of traditional "salchichón".

Growth and Expression of Virulence Genes of Listeria monocytogenes during the Processing of Dry-Cured Fermented "Salchichón" Manufactured with a Selected Lactilactobacillus sakei

The effect of the dry-cured fermented processing of "salchichón" inoculated with a selected strain of Lactilactobacillus sakei (205) on the growth and transcriptional response of three virulence genes (plcA, hly, and iap) of Listeria monocytogenes was evaluated. For this, three different batches of "salchichón" were analyzed: batch B (inoculated only with L. sakei), batch L (inoculated only with L. monocytogenes), and batch L + B (inoculated with both microorganisms). Sausages were ripened for 90 days according to a traditional industrial process. The processing of "salchichón" provoked a reduction in L. monocytogenes counts of around 2 log CFU/g. The downregulation of the expression of the three genes was found at the end of ripening when the water activity (aw) of "salchichón" was <0.85 aw. The combined effect on the reduction in L. monocytogenes counts together with the downregulation in the expression of the virulence genes throughout the "salchichón" processing could be of great interest to control the hazard caused by the presence of this pathogenic bacterium.

Effect of the Dry-Cured Fermented Sausage "Salchichón" Processing with a Selected Lactobacillus sakei in Listeria monocytogenes and Microbial Population

In the present work, the effect of processing of dry-cured fermented sausage “salchichón” spiked with the selected Lactobacillus sakei 205 was challenge-tested with low and high levels of L. monocytogenes. The evolution of the natural microbial population throughout the “salchichón” ripening was also evaluated. For this, a total of 150 “salchichón” were elaborated and divided into six equal cases which were inoculated with different levels of L. monocytogenes, and L. sakei 205. Afterwards, sausages were ripened for 90 days according to a typical industrial process. Moisture content (%) and water activity (a_w) decreased throughout the ripening up to values around 26% and 0.78, respectively. No differences for moisture content, a_w, pH, NaCl and nitrite concentration were observed between the analyzed cases. Lactic acid bacteria counts in the L. sakei 205 inoculated cases were always higher than 6 log CFU g⁻¹ during ripening. Enterobacteriaceae counts were reduced during ripening until non-detectable levels at the end of processing. Reductions in L. monocytogenes counts ranged from 1.6 to 2.2 log CFU g⁻¹; therefore, the processing of “salchichón” itself did not allow the growth of this pathogen. Reduction in L. monocytogenes was significantly higher in the cases inoculated with L. sakei 205.

Fatty Acid Composition of Salami Made by Meat from Different Commercial Categories of Indigenous Dairy Cattle

Simple Summary

The Cinisara is a Sicilian breed raised on pasture to produce the Caciocavallo Palermitano cheese. Even if it is penalized by competition with meat breeds, characterized by higher growth rate and yield, the production of fresh meat represents a considerable added value for the smallfarms. The meat of Cinisara is not appreciated, despite having a high content of iron, vitamin E, conjugated linoleic acid (CLA), and low content of lipids and cholesterol, above all due to incorrect management of the supply chain phases that negatively affects the quality of the final product. Alternative production such as bresaola and salami could contribute to the enhancement of Cinisara meat. The present study investigated the fatty acid profile of salamis produced by processing the meat of young bulls and adult cows with the addition of lard pork to provide additional information to that reported in a previous experiment on physicochemical and sensory properties. The results suggest the possibility of producing cured meats with Cinisara meat, even if the addition of pork lard mitigates some favorable effects deriving from the livestock system of this breed, based on grazing. Further studies should be conducted to investigate the possibility of making cured meats with beef only.

Abstract

In autochthonous dairy cattle farms, the production of salami could represent an alternative commercial opportunity. Therefore, a study was carried out to investigate the fatty acid (FA) composition of salami made using the meat from grazing (GB) or housed (HB) young bulls and grazing adult cows (AC) of Cinisara breed. The products were manufactured by adding 20% of pork lard. Animal category influenced the FA composition, although the addition of lard mitigated the differences found in fresh meat. The salami from GB showed higher polyunsaturated FA content (p ≤ 0.01) and, in particular, a higher level of linoleic acid (p ≤ 0.05), than from other animal categories. Salami made from AC meat showed lower polyunsaturated/saturated FA ratio (p ≤ 0.05), but a better n-6/n-3 ratio compared to HB (p ≤ 0.05), due to the lower content of linoleic acid. Multivariate analysis showed an important influence of animal category on FA composition due to age, feeding system and meat fat content of animals, despite the addition of lard.

Biochemical Changes during the Manufacture of Galician Chorizo Sausage as Affected by the Addition of Autochthonous Starter Cultures

In this work, the effect of the use of two autochthonous starter cultures (Lactobacillus sakei LS131 + Staphylococcus equorum SA25 (EQU), or L. sakei LS131 + Staphylococcus saprophyticus SB12 (SAP)) on the physicochemical, microbiological, proteolytic and lipolytic changes taking place during the manufacture of Galician chorizo, a traditional Spanish sausage, was studied. Three different batches (control (CNT), EQU and SAP) were manufactured in triplicate and analysed during the manufacturing process (samples were taken and analysed at 0, 2, 5, 9, 14, 21 and 30 days of ripening) for proximate composition, pH, aw, colour parameters, nitrogen fractions, free amino acids, biogenic amines, fat parameters and free fatty acids. The use of either of these two starter cultures slightly but significantly reduced the pH values during the fermentation and increased the percentage of transformation to nitrosyl-heme pigments as well as the a* and b* values in the final products. The two starters significantly decreased the Enterobacteriaceae counts in the final product, but without this microbial group completely disappearing. Both starter cultures significantly increased the α-amino acidic nitrogen and the total basic volatile nitrogen fractions during manufacturing, also increasing the free amino acid content and reducing the total biogenic amine content by approximately 20%. The SAP starter enhanced the lipolytic processes, increasing the free fatty acid content. Due to their performances, these two starter cultures seem to be suitable for increasing the quality and safety of the Galician chorizo sausage.

Effects of flavourzyme addition on physicochemical properties, volatile compound components and microbial community succession of Suanzhayu

Flavourzyme is known to promote protein decomposition, resulting in more peptides and amino acids which can improve the quality of fermented foods. In this study, the effects of flavourzyme addition on the fermentation of Suanzhayu fish were investigated. The results showed that the addition of 50 U/g flavourzyme reduced the water activity (a_w) of products and promoted the release of trichloroacetic acid (TCA)-soluble peptides and free amino acids (FAAs). Thus, the stability of the product was improved and its nutritional value was increased. In addition, with the addition of flavourzyme, Lactobacillus and Saccharomyces more quickly became the dominant genera in the fermentation. Furthermore, the formation of alcohols, aldehydes, and esters was promoted in flavourzyme addition group. Redundant analysis (RDA) indicated that Lactobacillus and Lactococcus play important roles in the formation of flavors, especially for the characteristic flavors of Suanzhayu. Flavourzyme addition may be a novel method to greatly improve the properties of Suanzhayu and shorten the fermentation time.

Application of isolated Lactobacillus sakei and Staphylococcus xylosus strains as a probiotic starter culture during the industrial manufacture of Tunisian dry-fermented sausages

For decades, lactic acid bacteria has been isolated and selected to be used as starter cultures in meat fermentation for standardization and management of quality of dry-fermented sausage which constitute a considerable challenge. The aim of this study was to evaluate the effect of Lactobacillus sakei strains, isolated from different origins, on qualities of dry-fermented sausages. These last, manufactured with different combinations of starter cultures (L. sakei + Staphylococcus xylosus), were ripened, using the same raw materials and conditions, for 45 days. Samples were collected during this period, and microbiological, physicochemical, fatty acid profile, and sensorial analyses determined. Lactic acid bacteria were the dominant flora during ripening. A desirable PUFA/SFA ratio, corresponding to 1:1.7 (0.6), was detected after 24 days of maturation in sausages inoculated by L. sakei BMG 95 and S. xylosus. Sensory analysis showed that fermented sausages manufactured with L. sakei and S. xylosus had a more desirable odor, flavor, and texture and consequently were preferred overall. In particular, sensory panellists preferred sausages produced with either L. sakei 23K or L. sakei BMG 95 when compared to fermented sausage produced with a commercial starter or no starter at all.

Microbiological properties and volatile compounds of salted-dried goose

Salted-dried goose is a traditional Turkish product with specific flavor that is produced by dry salting, post-salting, and subsequently air-drying of the goose carcass. In this study, the leg and breast parts of salted-dried goose carcasses were analyzed in terms of microbiological properties and volatile compounds. Lactic acid bacteria and Micrococcus-Staphylococcus bacteria constituted a significant part of microbiota in both leg and breast samples. The Enterobacteriaceae count was below the detectable level (<2 log cfu g^-1) in 60% of the leg samples and in 47% of the breast samples. The yeast-mold count was less than 5 log cfu g^-1 in 80% of both leg and breast samples. Many volatile compounds belonging to different chemical groups, including aldehydes, aliphatic and aromatic hydrocarbons, esters, alcohols, terpenes, ketones, sulfur compounds, and furans, were identified from samples. The breast samples showed a higher mean amount of hexanal than the leg samples. No significant difference was found between the breast and leg samples in terms of ketones and sulfur compounds. It was also determined that a considerable part of volatile compounds is formed by lipid oxidation.

MODERN PRODUCTION TRENDS OF FERMENTED MEAT PRODUCTS

The work aims to the generalization and analysis of the main problems of production of fermented meat products, which are reflected in scientific publications of the meat processing industry experts. The modern researches of scientists all over the world are aimed to the achievement of bio- and microbiological safety, structure formation, use of new kinds of raw materials, features of color formation, formation of sensory properties, increase of biological value of smoked and uncooked products. The work emphasizes that the quality of finished products and the stability of the technological process depends on the quality of raw materials, the properties of their own microbiota of raw materials and/or introduced starter cultures of microorganisms. The possibility of improving the sanitary condition of raw materials and reducing the impact of pathogenic microorganisms due to the use of ultrasound, hydrostatic high pressure, high-intensity pulsating electric field, cold plasma are described in the work. Also, in addition to physical processing methods, the use of competing microflora, extracts of spicy-aromatic plants, combining salt mixtures, packaging are effective. It is stated that the formation of the structure of the finished product depends on the parameters of the technological process, the activity of exo-endoenzymes and prescription composition. It is shown that the color of fermented meat products and their stability depend on the content of natural pigments and the conditions of their interaction with nitrites under the action of microorganisms with nitrite reductase activity and pH of the environment. The possibility of obtaining a characteristic pink-red color of meat products without the use of nitrites was noted. The results of investigations of the possibility of varying the organoleptic parameters of the finished product by modeling the ingredient composition and fermentation conditions are presented. The possibilities of creation of new types of fermented meat products of functional purpose by the introduction of ω-3 fatty acids, probiotics, macro-, microelements and more are described.

Trends in microbial control techniques for poultry products

Fresh poultry meat and poultry products are highly perishable foods and high potential sources of human infection due to the presence of several foodborne pathogens. Focusing on the microbial control of poultry products, the food industry generally implements numerous preventive measures based on the Hazard Analysis and Critical Control Points (HACCP) food safety management system certification together with technological steps, such as refrigeration coupled to modified atmosphere packaging that are able to control identified potential microbial hazards during food processing. However, in recent years, to meet the demand of consumers for minimally processed, high-quality, and additive-free foods, technologies are emerging associated with nonthermal microbial inactivation, such as high hydrostatic pressure, irradiation, and natural alternatives, such as biopreservation or the incorporation of natural preservatives in packaging materials. These technologies are discussed throughout this article, emphasizing their pros and cons regarding the control of poultry microbiota and their effects on poultry sensory properties. The discussion for each of the preservation techniques mentioned will be provided with as much detail as the data and studies provided in the literature for poultry meat and products allow. These new approaches, on their own, have proved to be effective against a wide range of microorganisms in poultry meat. However, since some of these emergent technologies still do not have full consumer's acceptability and, taking into consideration the hurdle technology concept for poultry processing, it is suggested that they will be used as combined treatments or, more frequently, in combination with modified atmosphere packaging.