End Of Ripening Research Articles

Determination of optimum ripening time in hard cooked cheeses (Reggianito type) using survival analysis statistics: Modified versus traditional cheese making technology.

In this work, we determined optimum ripening time of hard cooked cheeses made by traditional technology or by an innovative process aimed at accelerating flavor formation. For that purpose, we applied survival analysis statistics. Experimental cheese making (E) included homogenization of milk fat, unpasteurizedcheesemilk, changes in cooking temperature, and a curd-washing step, while traditional cheese making (T) followed a classic hard-cooked cheese making. Cheeses were ripened for 215 days and samples were analyzed at 76, 112, 128, 152, and 215 days. Consumers (250) were recruited and divided into five groups of 50 consumers for each stage. At each sampling time, consumers assessed whether the sample was "under-ripe," "ok," or "over-ripe." Optimum ripening time could be estimated only for E cheeses, with a high percentage of rejection. For T cheeses, it was not possible to determine the optimum ripening time because the rejection by over-ripening was never reported. We verified consumer segmentation: a small percentage found E cheese under-ripe and a high percentage found it over-ripe. Many consumers qualified E cheeses as too spicy, especially at the end of ripening. Spicy flavor is usually perceived before than the texture and evidenced an acceleration of the flavor formation. We concluded that the innovative intervention in cheese making technology was successful in accelerating cheese ripening. It also had potential to develop a new cheese product targeted at consumers who chose/prefer good spicy flavor. PRACTICAL APPLICATION: Survival analysis is a useful methodology to determine the optimum ripening time of foods based on consumer data. In this work, it evidenced that the proposed innovative cheese making was successful in accelerating the formation of cheese flavor, and had the potential to develop a new cheese product targeted at consumers who chose/prefer good spicy flavor.

Effect of forage type, season, and ripening time on selected quality properties of sheep milk cheese

The aim of this research was to study changes in the microbial populations, free AA profile, biogenic amine content, and sensory characteristics of ripened cheeses (100 and 180 d) produced in different seasons (summer, autumn, winter, and spring) from pasteurized sheep milk from 8 commercial flocks fed hay or silage diets. Twenty-one individual AA and 6 biogenic amines were determined by ultra-high performance liquid chromatography. Type of conserved forage for sheep feeding did not affect the variables studied, which is of great interest because hay and silage are low-cost ingredients for sheep feeding. Proteolysis led total free AA concentrations ranging between 35,179.26 and 138,063.71 mg/kg of cheese at 180 d of ripening. γ-Aminobutyric acid, which has been associated with beneficial effects on human health, was the second most abundant AA in all cheese samples, accounting for 15% of total free AA. Spring cheeses showed 2-fold higher concentrations of γ-aminobutyric acid than summer and autumn cheeses at the end of ripening. Overall, spring, winter, and autumn cheeses had lower average concentration of biogenic amines (431.99 mg/kg of cheese) than summer cheeses (825.70 mg/kg of cheese) as well as better sensory characteristics. Therefore, this study could provide the dairy industry with useful information for producing cheeses with valuable nutritional and sensory quality for consumers.

Identification of antioxidant peptides from cheddar cheese made with Lactobacillus helveticus

The aim of the study was to identify potential antioxidant peptides from cheese made with Lactobacillus helveticus 1.0612. The results demonstrated that the nutrient composition of cheese was not affected by the addition of Lactobacillus helveticus, and Lactobacillus helveticus maintained its viability at 7.64 log CFU/g at the end of ripening. Lactobacillus helveticus can significantly increased the antioxidant activity of cheese during ripening time (P < 0.05), and the antioxidant activity reached maximum at the 5th month of ripening time. The potential antioxidant activity water soluble extracts of cheese were fractioned and purified by ultrafiltration and size exclusion technology. The fraction with the highest antioxidant activity was subjected to Q Exactive Plus-Orbitrap mass spectrometer for the identification of peptides. 15 peptides were identified from the most active fractions, and mainly derived from β- and αs1-casein. The size of the identified peptide sequence varied from 6 to 14 amino acid residues, and the molecular weight ranges from 700 to 1300 Da. 10 peptides contained at least one hydrophobic amino acids proline residue. Peptides VLPVPQK and EDVPSER have been reported for their antioxidant activity, DKIHPF for ACE-inhibitory activity. Moreover, several new peptides (EMPFPK, KEMPFPK, SDIPNPIGSENSEK), with potential antioxidant activity, have been identified.

Influence of mixed starters on the degradation of proteins and the formation of peptides with antioxidant activities in dry fermented sausages

This study aimed to investigate the influence of mixed starters (Lactobacillus plantarum CD101 and Staphylococcus simulans NJ201) with a high protease activity on the degradation of proteins and the formation of peptides with antioxidant activities during the fermentation and ripening of dry fermented sausages. The starters mainly affected the proteolytic characteristics during the fermentation stage, and their beneficial effects persisted until the end of ripening. Electrophoresis analysis indicated that the starters could more rapidly and severely hydrolyze proteins on days 1 and 4 than on other days. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and ferric ion reducing antioxidant power (FRAP) value of the peptides extracted from the starter-inoculated group significantly increased (P < 0.05) compared with those from the control group. After 23 days of ripening, the free amino acid (FAA) content also increased significantly (P < 0.05) because of the addition of starters. Thus, mixed starters could help delay oxidative changes in dry fermented sausages.

Biopreservation and probiotic potential of a large set of lactic acid bacteria isolated from Brazilian artisanal cheeses: From screening to in product approach

The increasing interest in products with functional properties has encouraged the search for new lactic acid bacteria (LAB) present in natural sources, as traditional fermented foods. In this study, a large set of wild LAB isolates (n = 220) from Brazilian artisanal cheeses (BAC) were assessed for their probiotic and biopreservation potential. First, the rational selection was performed. From the tested isolates, 92 (41.8 %) were resistant to low pH (2 and 3). These isolates were submitted to bile salt (0.4 % Oxgall powder) resistance, and 22 were selected and submitted to adhesion assays. The autoaggregation values ranged from 68.5–99% and were considered moderate to high (20–70 %). Hydrophobicity values varied significantly between LAB (5.0–64.3%), and seven isolates presented values higher than 40 %. All selected LAB (n=22) were capable of adhering to Caco-2 (> 70 %) cells, and none isolate displayed any tested gene for biogenic amine production. Most isolates (18/22) showed less than 1 log CFU reduction after passage through the simulated gastrointestinal tract (GIT) conditions. A total of twenty isolates satisfied key in vitro criteria to be considered as probiotics. A hierarchical cluster analysis (HCA) was performed, and two clusters were observed, showing high variability between Lactobacillus plantarum isolates regarding adhesion properties and survival to GIT stress and one influence of the source of isolation on these properties. After screening, the antimicrobial activity of Lb. plantarum (1QB77) was tested in microcheeses in which survival of two relevant pathogenic bacteria (Staphylococcus aureus and Listeria monocytogenes) was monitored along ripening and after a simulated GIT passage, concomitantly. L. plantarum (1QB77) has shown the ability to reach high counts (∼ 9 log CFU/g) at the end of ripening. This isolate was also able to reduce counts of S. aureus and L. monocytogenes in microcheeses in approx. 2.3 and 2.5 log CFU/g, respectively, until the 21st day of ripening; and about 3.2 and 3.5 log CFU/g after simulated GIT passage. Overall, the assessment of the probiotic properties of a large set of LAB was fundamental for gaining insights on the technological, functional, and potential regional traits of wild LAB isolates that can be used to develop starter cultures for tailored applications.

Biochemical and microbiological properties of Edam cheese with black cumin oil

Edam cheese samples were prepared with the addition of different concentrations of black cumin (Nigella sativa L) oil (0.2, 0.4 and 0.6 % v/w). Significant differences (P≤0.05) in chemical composition and ripening indices among treated cheese sample (0.6 % oil) and control was observed in all examined parameters. The added black cumin oil increased cheese acidity from 0.79 % in control to 1.13 % in cheese with 0.6 % oil at fresh time, with continuously increase in all cheese samples during ripening. Soluble nitrogen/Total Nitrogen reached 15.91 % in cheese with higher level of black cumin oil at the end of ripening. Free amino acids recorded 1.21 g leucine/g cheese in Edam cheese with 0.6 % oil at end of ripening times. Free fatty acids increased with increasing level of oil in Edam cheese samples. Incorporation of black cumin oil in Edam cheese reduced the total viable count (5.97 log cfu/g), yeast & molds (1.00 log cfu/g) at the end of ripening and inhibited the growth of coliform groups. Proteolytic bacteria recorded higher counts (3.19 log cfu/g), while lipolytic bacteria recorded lower counts (2.59 log cfu/g) in Edam cheese with 0.6 % oil comparing to other cheese samples at 60 days of ripening. Panelists accepted the taste of Edam cheese with higher concentration of black cumin oil (0.6 %) with no complains on appearance and smell, while they favored the texture of Edam cheese with higher percentage of oil, then overall acceptability went to 0.6 % oil treated cheese.

Effect of ultrasound-assisted cold plasma pretreatment to obtain sea asparagus extract and its application in Italian salami

The effect of the glow discharge cold plasma pretreatment (CPT) was investigated on the ultrasound-assisted extraction (UAE) of phenolic compounds from sea asparagus Salicornia neei. The extract was applied in dry fermented sausage (Italian salami). Thermal extraction methods demand a long processing time, are highly energy-consuming and cause irreversible nutrient losses. It was found that CPT (discharge power of 14 W for 5 min) prior to UAE increased the antioxidant activity by 22% and 19% measured by the DPPH and ABTS assays, respectively. The S. neei extract showed high antioxidant activity, low antimicrobial activity, and was added to salami formulations with reduced-sodium nitrite content and no addition of sodium erythorbate. Despite a slight color change, lipid oxidation and texture parameters were similar to the control at the end of ripening. Furthermore, higher antioxidant activity was observed in S. neei extract supplemented salami with no impact on its sensory overall acceptability, indicating its potential as a natural alternative to synthetic additives.

Biogenic amine content during the production and ripening of Sremski kulen, Serbian traditional dry fermented sausage.

Sremski kulen is a wide diameter dry fermented sausage, produced from pork, seasoned with red spicy paprika, stuffed into pork cecum, and preserved by smoking, fermentation and drying. Due to specific ripening process, Sremski kulen is suitable for the accumulation of biogenic amines. Therefore, the aminogenesis was studied in traditionally produced Sremski kulen, taking into account the physicochemical parameters and microbial counts. The content of six biogenic amines (tryptamine, phenylethylamine, tyramine, histamine, putrescine, and cadaverine) was analyzed using high-performance liquid chromatography. The ripening process of Sremski kulen was slow followed by changes in aw and pH value as well as expressed proteolysis. The autochthonous microbiota showed pronounced decarboxylase activity. Tryptamine and phenylethylamine were detected at each examined ripening stage while histamine was not detected until the end of ripening (16.55±2.33mg/kg). Tyramine, cadaverine, and putrescine content significantly increased during the ripening period (p<.05). In the final product, cadaverine was the dominant biogenic amine (132.40±5.05mg/kg), followed by tyramine (115.80±15.46mg/kg) and putrescine (68.55±2.39mg/kg). Although the long ripening period greatly contributed to the accumulation of biogenic amines in final product, their content are not of concern from product safety aspects, but requires improvement in hygiene of production process.

The impact of sodium chloride reduction on Grana-type cheese production and quality.

With the aim to reduce the Na content, hard cheeses manufactured using the same technology as for Grana cheese (Grana-type) were salted using three brines containing different amounts of KCl (K-brines) and compared with control cheeses, salted with marine NaCl. A lower weight loss was observed in cheeses salted with K-brines (K-cheeses), whereas the yield and dry matter did not differ significantly between K-cheeses and controls. After 3 months of ripening (T3), the distribution of the Na cations (Na) was centripetal, with a higher Na concentration in the outer (0-3 cm of depth) layer, whereas the K cations (K) seemed to diffuse into the cheese more rapidly and homogeneously. Starting from the 6th month (T6), the distribution of both Na and K was stabilized through the different cheese layers. The use of the brine with the highest concentration of potassium (53.8% K) enabled us to successfully halve the Na content compared to the controls whereas, with the other brines, the reduction of Na was below 30%. At the end of ripening (T9), all the cheeses were without defects and the partial substitution of Na with K did not impact on the chemical composition, microbiological characteristics and ripening process. The sensory evaluation did not show any difference between K-salted and control cheeses in discriminant analysis.

Physicochemical and sensory evolutions of the lactic goat cheese Picodon in relation to temperature and relative humidity used throughout ripening

To produce a wide variety of cheeses, it is necessary to control the ripening process. To do that, artisanal goat cheeses were ripened to evaluate the effects of temperature (10 and 14°C) and relative humidity (RH; 88 and 98%) on (1) 16 physicochemical characteristics throughout ripening and (2) 19 sensory characteristics at the end of ripening (d 12). Whatever the ripening time, the physicochemical characteristics were strongly dependent on the daily productions, which affected the sensory perception of the cheeses. Both physicochemical and sensory characteristics were strongly reliant on RH, whereas only a few of the characteristics were influenced by temperature changes. On d 12, whatever the ripening temperature, an RH increase from 88% to 98% modified many cheese characteristics (core pH, lactate consumption, underrind thickening, dry matter content, and hardness). As a result of these physicochemical properties, changes in perception were observed: the cheeses ripened under 88% RH were dry and hard compared with those ripened under 98% RH. An RH of 98% led to an acceleration of the ripening process, inducing a slightly ammonia and milky flavor and a sticky and creamy texture in the mouth. However, cheeses ripened under 14°C and 98% RH were also indicative of overripened cheeses: a temperature of 14°C induced an acceleration of the ripening process due to physicochemical modifications compared with a temperature of 10°C. Nevertheless, when the cheeses on d 0 were still very humid and soft, those ripened under 98% RH collapsed and were overripened with a liquid underrind. This study provides a means for achieving a better and more rational control of the ripening process in artisanal lactic goat cheeses.

Evaluation of the bacterial diversity of Spanish-type chorizo during the ripening process using high-throughput sequencing and physicochemical characterization

Spanish-type chorizo is a fermented meat product that is highly appreciated by consumers. The physicochemical properties (pH, water activity (aw), total acidity (TA), and malonaldehyde content) were evaluated in the initial meat batter and at different ripening stages. Bacterial diversity and dynamics were also examined using high-throughput sequencing. A decrease in pH and aw was observed during ripening, while the TA and malonaldehyde contents increased significantly. This data correlated with the changes in lactic acid bacteria and enterobacteria populations. Total bacterial diversity in the initial samples was represented by Proteobacteria (44%) and Firmicutes (55%) phyla, where Pseudomonas (23%), Streptococcus (21%), Acinetobacter (14%), Bacillus (13%), and Brochothrix (11%) were the most abundant genera. In contrast, Firmicutes reached the highest frequency (~89%), with Lactobacillus and Streptococcus being the most represented at the end of ripening. Lactobacillus sakei, Pediococcus acidilactici, and Weissella thailandensis were identified by 16S rRNA gene analysis and were considered potentially responsible for the stability, microbiological safety, and sensory characteristics of this product.

Application of Autochthonous Lactobacillus Strains as Biopreservatives to Control Fungal Spoilage in Caciotta Cheese.

Fungal spoilage is one of the main causes of economic losses worldwide in the food industry. In the last years, consumer's demands for preservative-free processed foods have increased as a result of growing awareness about the health hazards associated with chemicals. Lactic acid bacteria have been extensively studied for their antibacterial and antifungal potential in order to be used as biopreservatives. The first objective of this study was to investigate in vitro the antifungal activity of autochthonous Lactobacillus strains against moulds commonly associated with cheese spoilage. Then, the Lactobacillus strains with the highest inhibitory effect and broadest spectrum were tested in single or mixed cultures against Penicillium chrysogenum ATCC 9179 and Aspergillus flavus ATCC 46283 on miniature Caciotta cheese produced at laboratory scale to evaluate in situ their ability to prevent mould growth and to determine their impact on cheese organoleptic properties and starter culture activity. The growth of the starter lactococcal population exhibited similar trend and values during ripening, suggesting that the addition of lactobacilli did not influence its growth and survival. Inhibition of P. chrysogenum inoculated in the milk was determined in cheeses produced with single or mixed Lactobacillus adjuncts as compared to cheeses without adjunct. The mixed adjunct cultures resulted in more effective, significantly reducing mould counts of more than 2 log units at the end of ripening. The application of the adjunct cultures resulted in a delay in mycelial growth of P. chrysogenum and A. flavus inoculated on the cheese surface as well. Finally, we found no significant differences among samples for the sensory parameters evaluated that received similar ratings. Our results indicate that the selected Lactobacillus strains may have a potential effect in controlling mould contamination on cheeses. Further studies are currently being carried out to identify the molecules responsible for the antifungal activity.

Histochemical and immunohistochemical analysis of enzymes involved in phenolic metabolism during berry development in Vitis vinifera L.

Phenolics are involved in many of plants' biological functions. In particular, they play important roles in determining the quality of grape berries and the wine made from them, and can also act as antioxidants with beneficial effects for human health. Several enzymes are involved in the synthesis of phenolic compounds. Among them, stilbene synthase (STS) is a key to the biosynthesis of stilbenes, which are considered to be important secondary metabolites in plants. Other enzymes, such as polyphenol oxidase (PPO) and peroxidase (POD), are involved in the degradation of phenolics, and become activated during late stages of berry ripening. In the present study, Vitis vinifera L. berries were sampled at eight stages of development, from 10days after anthesis to late harvest. The PPO and POD enzymatic activities were determined at each stage. The presence of STS, PPO, and POD proteins in the grape exocarp and mesocarp was detected immunohistochemically and histochemically. The amount and intensity of the immunohistochemical and histochemical signals correlate with the variations in enzyme activities throughout fruit development. Strong STS immunoreactivity was detected until the onset of ripening. Labeled tissue increased gradually from mesocarp to exocarp, showing an intense signal in epidermis. At subcellular level, STS was mainly detected in cytoplasm grains and cell walls. The amount of PPO immunoreactivity increased progressively until the end of ripening. The PPO signal was detected in hypodermal layers and, to a lesser extent, in mesocarp parenchyma cells, especially in cytoplasm grains and cell walls. Finally, POD activity was stronger at the onset of ripening, and the POD histochemical signal was mainly detected in the cell walls of both exocarp and mesocarp tissue.

Effects of chitosan as a surface fungus inhibitor on microbiological, physicochemical, oxidative and sensory characteristics of dry fermented sausages

The study aimed to improve the quality characteristics of Turkish dry-fermented sausages (sucuk) using different concentrations of chitosan (CH) coating as superficial mold inhibitor. The sausages were treated (w/w) with chitosan (0.2%, CH1; 0.5%, CH2 and 1%, CH3), potassium sorbate (20%, PS), acetic acid (1%, AA) and distilled water. Treatment with PS and CH3 resulted in a remarkable reduction of mold and yeast counts in the sausages and on casings at the end of ripening. Total aerobic mesophilic bacteria and lactic acid bacteria (LAB) varied from 7.19–7.29 to 9.01–9.27 and from 6.37–6.44 to 8.53–8.93 log CFU/g at day 0 and 12, respectively. Treatment with chitosan did not affect the natural microbiota of the sausages. Enterobacteriaceae counts were lowered from 5.79–5.89 to 2.08–2.53 log CFU/g by chitosan. Moreover, the rate of lipid oxidation in the sausages decreased by chitosan treatment. Sensory attributes were also notably enhanced in the cooked sausages treated with chitosan.

Microbial dynamics of model Fabriano-like fermented sausages as affected by starter cultures, nitrates and nitrites

The present study promotes the valorization of Fabriano-like fermented sausages, which are central-Italy salami with an origin that dates to the early 17th century, for the possible future selection of autochthonous starter cultures to be used with respect to local traditions. To the best of the authors' knowledge, this study represents the first attempt to define the microbial dynamics in Fabriano-like fermented sausage and the effect of nitrates/nitrites and starter cultures on its natural bacterial biota. Culture and RNA-based techniques (RT-PCR-DGGE and Illumina sequencing) were used to assess the microbial ecology of model Fabriano-like fermented sausages together with the impact of starter cultures and different nitrate and nitrite concentrations. The meat batter was used to produce two batches of fermented sausages that were prepared as follows: i) without commercial starters or ii) with the use of starter cultures composed of Pediococcus pentosaceus and Staphylococcus xylosus. Each batch was further divided into three different batches with the addition of 0/0 mg kg−1 nitrate/nitrite, 75/60 mg kg−1 nitrate/nitrite and 150/125 mg kg−1 nitrate/nitrite to the first, second and third batch, respectively. The samples, which were produced in triplicate, were analyzed on the day of production and after 7, 21, and 42 days of ripening. Enterobacteriaceae counts were always higher in model Fabriano-like sausages produced without the use of starter cultures at all of the sampling times irrespective of the tested nitrate/nitrite concentrations. Lactobacilli counts were positively influenced by the starters, although this influence was not evident over time; moreover, the effect of nitrates and nitrites on the counts of lactobacilli differed over time. As a general trend, coagulase-negative cocci counts were apparently not influenced by the tested nitrate/nitrite concentrations. Regarding the effect of nitrates/nitrites on the microbial diversity revealed by RT-PCR-DGGE, the higher the concentration, the lower the presence of some genera/species such as Pseudomonas spp., Serratia liquefaciens and Staphylococcus spp. However, Illumina sequencing detected Pseudomonas spp. as a minority species after 7, 21 and 42 days of ripening irrespective of the nitrate/nitrite concentration. The presence of Staphylococcus species was highlighted by both RT-PCR-DGGE and Illumina sequencing at all of the stages of ripening, although its presence was massively detected in fermented sausages produced without the use of nitrates/nitrites at the end of ripening. Overall, the data collected clearly highlighted the dominance of Lactobacillus sakei in all of the fermented sausages during ripening (from day 7 to day 42) and irrespective of the nitrate/nitrite concentration and added starter cultures. Moreover, Pediococcus spp. was principally detected in model Fabriano-like fermented sausage with added starter cultures irrespective of the nitrate/nitrite concentration.

Effect of Lactobacillus rhamnosus on the antioxidant activity of Cheddar cheese during ripening and under simulated gastrointestinal digestion

This study was aimed at evaluating Lactobacillus rhamnosus for its ability to affect the antioxidant activity of Cheddar cheese during ripening and digestion. The effect of probiotic on the proteolytic patterns and antioxidant activity of Cheddar cheese during ripening was analysed. Three fractions (>10 kDa, 3–10 kDa, and <3 kDa) were separated at the end of ripening of cheese and after digestion. The results demonstrated that Lactobacillus sps dominated all stages of ripening cheese and maintained their viability at 8.44 log CFU/g at the end of ripening. The proteolysis concentrations were significantly higher in probiotic cheeses and the antioxidant activity was at its maximum at the end of ripening. Cheeses made with added Lactobacillus rhamnosus had significantly higher proteolytic activity and antioxidant activity (P < 0.05) than those without probiotics during the entire ripening time. After digestion, the number of bacteria in cheese decreased significantly (P<0.05), but the polypeptide content was increased by 37.97% and the DPPH radical scavenging ability and reducing power were increased by 7.46% and 17.58%. More small peptides were produced after digestion and the antioxidant activity of cheese correlated with proteolysis and production of small molecule polypeptides that were further enhanced upon incorporation of probiotics. The total acceptability of cheese was not affected by the addition of probiotic bacteria.

Microbiological, chemical-physical and sensory characteristics of Fabriano salami from pigs fed Oregano vulgaris extract.

This study aimed at evaluating the effect of Oregano vulgaris extract supplementation of heavy pig diet on the microbiological, chemical-physical and sensory characteristics of Fabriano salami. Fabriano salamis were produced processing meat derived from pigs belonging to two dietary groups of 16 pigs each: CTRL group fed a commercial pelleted feed, and OR group fed the CTRL diet integrated with 0.2% of oregano extract. Ten salamis per group were collected at 0, 7, 20 and 45 days of ripening and analysed for total viable count, enumeration of Enterobacteriaceae, Enterococcus spp, coagulase negative and positive staphylococci, Lactobacillus spp., Lactococcus spp., presence of Salmonella spp. and Listeria monocytogens, pH, water activity (aw) and colour (CIE L*a*b* colour system). At the end of the ripening (day 45) chemical composition (AOAC, 1990), total antioxidant capacity (ORACFL), thiobarbituric reactive substances (TBARS), total phenolic content (TPC) (Folin-Ciocalteu method) and consumer tests were performed. The integration of oregano extract in pig diets did not interfere with the microbial evolution, chemical composition, pH and aw. After 20 days of ripening the OR salami were redder then CTRL samples, which were also yellower at the end of ripening. Furthermore, the diet has significantly improved the oxidative status, the polyphenolic content and antioxidant power in OR salami. The consumers gave a higher score to OR salami in informed condition.

Yeast community in traditional Portuguese Serpa cheese by culture-dependent and -independent DNA approaches

This study investigated the yeast community present in the traditional Portuguese cheese, Serpa, by culture-dependent and -independent methods. Sixteen batches of Serpa cheeses from various regional industries registered with the Protected Designation of Origin (PDO) versus non-PDO registered, during spring and winter, were used. Irrespective of the producer, the yeast counts were around 5log CFU/g in winter and, overall, were lower in spring. The yeast species identified at the end of ripening (30days), using PCR-RFLP analysis and sequencing of the 26S rRNA, mainly corresponded to Debaryomyces hansenii and Kluyveromyces marxianus, with Candida spp. and Pichia spp. present to a lesser extent. The culture-independent results, obtained using high-throughput sequencing analysis, confirmed the prevalence of Debaryomyces spp. and Kluyveromyces spp. but, also, that Galactomyces spp. was relevant for three of the five producers, which indicates its importance during the early stages of the cheese ripening process, considering it was not found among the dominant viable yeast species. In addition, differences between the identified yeast isolated from cheeses obtained from PDO and non-PDO registered industries, showed that the lack of regulation of the cheese-making practice, may unfavourably influence the final yeast microbiota. The new knowledge provided by this study of the yeast diversity in Serpa cheese, could be used to modify the cheese ripening conditions, to favour desirable yeast species. Additionally, the prevalent yeast isolates identified, Debaryomyces hansenii and Kluyveromyces spp., may have an important role during cheese ripening and in the final sensorial characteristics. Thus, the study of their technological and functional properties could be relevant, in the development of an autochthonous starter culture, to ensure final quality and safety of the cheese.

Fate of Listeria innocua during production and ripening of smeared hard cheese made from raw milk

The fate of 2 different Listeria innocua strains was analyzed during the production and ripening of smeared raw milk Greyerzer cheese (Gruyère). These strains were used as surrogates for the pathogenic Listeria monocytogenes, as they are physiologically very similar. Bacterial cells were added to the cheese milk at levels of 105 cfu/mL. During the first 24 h of cheese making, the number of the test strains decreased to a level of below 102 cfu/g. Obviously, the cooking temperature of 56°C and the subsequent slight temperature decrease to 50°C within 70 min contributed to a distinct reduction of Listeria counts. The counts in the cheese cores did not exceed 103 cfu/g within 12 wk of cheese ripening and Listeria was not detectable after 24 wk. In contrast to the cores of the cheeses of the 4 batches in this study, their rinds always contained a high listerial load of approximately 106 to 108 cfu/g throughout the entire ripening period. The smeared surface showed an increase of pH to alkaline values, corresponding to smear microbiota development. Coryneforms and Staphylococcus counts were stable at >107 cfu/cm2 over 175 d, whereas yeast counts decreased to about 105 cfu/cm2 at the end of ripening. The study shows that the smear culture had no noticeable anti-listerial potential. When removing the rind or portioning such smeared cheese loaves with a cutting device, a postprocess contamination of the core might occur, thus presenting a major hygienic risk.

The incorporation of alpha-tocopherol and functional doses of phytosterol esters during cheesemaking does not affect DNA or mRNA dynamics of Streptococcus thermophilus and Lactococcus lactis throughout and after the end of ripening

Tocopherols and phytosterols are lipid-soluble molecules which have been widely used in the food industry. Nevertheless, the influence of these compounds on the performance of starter lactic acid bacteria (SLAB) in fermented foods has received little attention. Here, we assessed the behavior of Streptococcus thermophilus and Lactococcus lactis during the ripening of a functional Port Salut light cheese elaborated with these SLAB and with alpha-tocopherol and phytosterol esters as bioactive molecules. Functional and control cheeses were manufactured at an industrial plant and sampled at 7, 21, 40, 60 and 90 days after elaboration for real-time quantitative PCR (qPCR) or reverse transcription-qPCR (RT-qPCR) experiments. Target DNA and mRNA from both SLAB were detected after 90 days of elaboration in both functional and control cheeses, supporting their potential role in generating flavor metabolites. Furthermore, here we showed for the first time that the addition of alpha-tocopherol and functional doses of phytosterols did not affect DNA or mRNA dynamics of these SLAB during cheesemaking, throughout and after the end of ripening. Therefore, our results support the use of cheese manufactured with both S. thermophilus and L. lactis as an optimal delivery system for these beneficial bioactive compounds.