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Dive into the research topics where Jorge Reinheimer is active.

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Featured researches published by Jorge Reinheimer.


Food Research International | 2000

Survival of probiotic microflora in Argentinian yoghurts during refrigerated storage

C.G Vinderola; N Bailo; Jorge Reinheimer

The survival of Bifidobacterium bifidum BBI and Lactobacillus acidophilus LAI in reduced-fat (liquid) and full-fat (set) yoghurts produced with two commercial lactic starter cultures (SID and SISD) was investigated. The viability of the probiotic bacteria was also assayed in milk acidified with lactic acid at different pH values. Samples were stored at 5°C for up to 4 weeks. There was a great variability in the survival ability of the probiotic cultures in the two yoghurt types. L. acidophilus LAI demonstrated, in general, a lower resistance to the yoghurt environment than B. bifidum BBI. On the other hand, the full-fat yoghurt was a more inhibitory medium than the reduced-fat one, especially for B. bifidum BBI. Regarding the lactic starters used, the results showed that the culture SISD was clearly more inhibitory for both probiotic organisms than the culture SID. The loss of cell viability in yoghurt samples was different (higher in some cases and lower in others) from that due to lactic acid only. In general, pH values of 4.5 or lower jeopardised the cell viability of the probiotic organisms in yoghurt stored at 5°C. This work shows the importance of selecting a suitable combination of probiotic strains and starter cultures when different yoghurt types are formulated.


Food Microbiology | 2011

Characterization and probiotic potential of Lactobacillus plantarum strains isolated from cheeses

Miriam Zago; Maria Emanuela Fornasari; Domenico Carminati; Patricia Burns; Viviana Suárez; Gabriel Vinderola; Jorge Reinheimer; Giorgio Giraffa

Ninety-eight Lactobacillus plantarum strains isolated from Italian and Argentinean cheeses were evaluated for probiotic potential. After a preliminary subtractive screening based on the presence of msa and bsh genes, 27 strains were characterized. In general, the selected strains showed high resistance to lysozyme, good adaptation to simulated gastric juice, and a moderate to low bile tolerance. The capacity to agglutinate yeast cells in a mannose-specific manner, as well as the cell surface hydrophobicity was found to be variable among strains. Very high β-galactosidase activity was shown by a considerable number of the tested strains, whereas variable prebiotic utilization ability was observed. Only tetracycline resistance was observed in two highly resistant strains which harbored the tetM gene, whereas none of the strains showed β-glucuronidase activity or was capable of inhibiting pathogens. Three strains (Lp790, Lp813, and Lp998) were tested by in vivo trials. A considerable heterogeneity was found among a number of L. plantarum strains screened in this study, leading to the design of multiple cultures to cooperatively link strains showing the widest range of useful traits. Among the selected strains, Lp790, Lp813, and Lp998 showed the best probiotic potential and would be promising candidates for inclusion as starter cultures for the manufacture of probiotic fermented foods.


International Journal of Food Microbiology | 2003

Inactivation of Lactobacillus delbrueckii bacteriophages by heat and biocides

Andrea Quiberoni; Daniela M. Guglielmotti; Jorge Reinheimer

The effect of several biocides and thermal treatments on the viability of four Lactobacillus delbrueckii phages was investigated. Time to achieve 99% inactivation of phages at 63 and 72 degrees C in three suspension media (Tris Magnesium Gelatin (TMG) buffer, Man Rogosa Sharpe (MRS) broth and reconstituted nonfat dry skim milk (RSM)) was calculated. Thermal resistance depended on the phage considered, but a marked heat-resistance was exhibited by one phage (Ib(3)) since its high titre suspensions were completely inactivated only after 45 min at 72 degrees C or 15 min at 90 degrees C. A clear protective effect of the milk was revealed when the three suspension media were compared. As regards to the effects of biocides on phages, only peracetic acid was found to be effective for inactivating high titre suspensions. Ethanol, even at a concentration of 100%, was not suitable to assure no surviving phage particles and isopropanol turned out to be less effective than ethanol. Sodium hypochlorite at 200-400 ppm inactivated the phages completely, except phage Ib(3), which was only destroyed after treatments with 1200 ppm. The diversity observed in the heat and biocide resistance of L. delbrueckii phages is useful to establish a basis for adopting the most effective thermal and chemical treatments for inactivating them in dairy plants and laboratory environments.


Journal of Dairy Science | 2008

Probiotic Crescenza Cheese Containing Lactobacillus casei and Lactobacillus acidophilus Manufactured with High-Pressure Homogenized Milk

Patricia Burns; Francesca Patrignani; Diana I. Serrazanetti; Gabriel Vinderola; Jorge Reinheimer; Rosalba Lanciotti; Maria Elisabetta Guerzoni

High-pressure homogenization (HPH) is one of the most promising alternatives to traditional thermal treatment of food preservation and diversification. Its effectiveness on the deactivation of pathogenic and spoilage microorganisms in model systems and real food is well documented. To evaluate the potential of milk treated by HPH for the production of Crescenza cheese with commercial probiotic lactobacilli added, 4 types of cheeses were made: HPH (from HPH-treated milk), P (from pasteurized milk), HPH-P (HPH-treated milk plus probiotics), and P-P (pasteurized milk plus probiotics) cheeses. A strain of Streptococcus thermophilus was used as starter culture for cheese production. Compositional, microbiological, physicochemical, and organoleptic analyses were carried out at 1, 5, 8, and 12 d of refrigerated storage (4 degrees C). According to results obtained, no significant differences among the 4 cheese types were observed for gross composition (protein, fat, moisture) and pH. Differently, the HPH treatment of milk increased the cheese yield about 1% and positively affected the viability during the refrigerated storage of the probiotic bacteria. In fact, after 12 d of storage, the Lactobacillus paracasei A13 cell loads were 8 log cfu/ g, whereas Lactobacillus acidophilus H5 exhibited, in P-P cheese, a cell load decrease of about 1 log cfu/g with respect to the HPH-P cheese. The hyperbaric treatment had a significant positive effect on free fatty acids release and cheese proteolysis. Also, probiotic cultures affected proteolytic and lipolytic cheese patterns. No significant differences were found for the sensory descriptors salty and creamy among HPH and P cheeses as well as for acid, piquant, sweet, milky, salty, creamy, and overall acceptance among HPH, HPH-P, and P-P Crescenza cheeses.


Letters in Applied Microbiology | 2004

Thermal and chemical resistance of Lactobacillus casei and Lactobacillus paracasei bacteriophages

M.L. Capra; A. Quiberoni; Jorge Reinheimer

Aims:  The survival of two collection Lactobacillus casei and L. paracasei bacteriophages when subjected to thermal and chemical treatments was investigated.


Journal of Applied Microbiology | 2006

Phages of Lactobacillus casei/paracasei: response to environmental factors and interaction with collection and commercial strains

M.L. Capra; Andrea Quiberoni; Jorge Reinheimer

Aim:  To investigate the influence of several environmental factors on the viability and cell‐adsorption for two Lactobacillus casei/paracasei bacteriophages (PL‐1 and J‐1).


Journal of Food Protection | 2002

Effectiveness of thermal treatments and biocides in the inactivation of Argentinian Lactococcus lactis phages.

Viviana Suárez; Jorge Reinheimer

The thermal and chemical resistance levels of four autochthonal bacteriophages of Lactococcus lactis subsp. lactis, isolated from cheese processes, was investigated. The times required to obtain 99% inactivation of phages (T99) at 63 and 72 degrees C in three suspension media (M17 broth, reconstituted commercial nonfat skim milk, and Tris magnesium gelatin buffer) were determined. Thermal resistance was dependent on the phage studied, and the results of this study demonstrate that pasteurization treatments used in dairy industries may leave viable viral particles in milk. It was possible to determine that M17 broth was generally the least protective medium, while phosphate buffer was the most protective one. Peracetic acid (0.15%, vol/vol) was the most effective viricidal agent, with exposures of 5 min being sufficient to inactivate high-titer phage suspensions (>10(6) PFU/ml). To achieve total inactivation (<10 PFU/ml) of viral suspensions, sodium hypochlorite was effective at 100 ppm for only two phages, while the other two phages needed concentrations of 200 and 300 ppm. Ethanol at concentrations of 100 and 75% proved to be very efficient in inactivating phages, but isopropanol was not effective against them.


Journal of Food Protection | 1999

Inactivation of Lactobacillus helveticus bacteriophages by thermal and chemical treatments.

Andrea Quiberoni; Viviana Suárez; Jorge Reinheimer

The effect of several biocides and thermal treatments on the viability of four Lactobacillus helveticus phages was investigated. Times to achieve 99% inactivation of phages at 63 degrees C and 72 degrees C in three suspension media were calculated. The three suspension media were tris magnesium gelatin buffer (10 mM Tris-HCl, 10 mM MgSO4, and 0.1% wt/vol gelatin), reconstituted skim milk sterile reconstituted commercial nonfat dry skim milk, and Man Rogosa Sharpe broth. The thermal resistance depended on the phage considered, but a treatment of 5 min at 90 degrees C produced a total inactivation of high titer suspensions of all phages studied. The results obtained for the three tested media did not allow us to establish a clear difference among them, since some phages were more heat resistant in Man Rogosa Sharpe broth and others in tris magnesium gelatin buffer. From the investigation on biocides, we established that sodium hypochlorite at a concentration of 100 ppm was very effective in inactivating phages. The suitability of ethanol 75%, commonly used to disinfect utensils and laboratory equipment, was confirmed. Isopropanol turned out to be, in general, less effective than ethanol at the assayed concentrations. In contrast, peracetic acid (0.15%) was found to be an effective biocide for the complete inactivation of all phages studied after 5 min of exposure. The results allowed us to establish a basis for adopting the most effective thermal and chemical treatments for inactivating phages in dairy plant and laboratory environments.


International Dairy Journal | 1996

The lactic acid microflora of natural whey starters used in Argentina for hard cheese production

Jorge Reinheimer; Andrea Quiberoni; P. Tailliez; Ana Binetti; V.B. Suárez

Abstract A total of 56 samples of natural whey starters, obtained by two sampling plans and employed for Argentinian hard cheese production, were examined. Seasonal changes in technological (pH, acidity, and acidifying and proteolytic activities) and microbiological (lactic acid microflora characteristics) parameters were analyzed. Furthermore, phage resistance and IS 1201 identification were studied among Lactobacillus helveticus isolates. Although technological characteristics of the cultures did not show significant variations, the relative proportion of Lb. helveticus and Lb. delbrueckii subsp. lactis was different between sampling 1 and 2. As a consequence, frequences of fast, intermediate and slow bacterial variants were also variable. On the other hand, lactic acid microflora showed a rather low tolerance to NaCl. Among Lb. helveticus strains, phage resistance was widespread and the presence of IS 1201, a specific insertion sequence for this species, was also demonstrated.


International Journal of Food Microbiology | 2010

Inside the adaptation process of Lactobacillus delbrueckii subsp. lactis to bile

Patricia Burns; Borja Sánchez; Gabriel Vinderola; Patricia Ruas-Madiedo; Lorena Ruiz; Abelardo Margolles; Jorge Reinheimer; Clara G. de los Reyes-Gavilán

Progressive adaptation to bile might render some lactobacilli able to withstand physiological bile salt concentrations. In this work, the adaptation to bile was evaluated on previously isolated dairy strains of Lactobacillus delbrueckii subsp. lactis 200 and L. delbrueckii subsp. lactis 200+, a strain derived thereof with stable bile-resistant phenotype. The adaptation to bile was obtained by comparing cytosolic proteomes of both strains grown in the presence or absence of bile. Proteomics were complemented with physiological studies on both strains focusing on glycolytic end-products, the ability to adhere to the human intestinal epithelial cell line HT29-MTX and survival to simulated gastrointestinal conditions. Protein pattern comparison of strains grown with and without bile allowed us to identify 9 different proteins whose production was regulated by bile in both strains, and 17 proteins that showed differences in their levels between the parental and the bile-resistant derivative. These included general stress response chaperones, proteins involved in transcription and translation, in peptidoglycan/exopolysaccharide biosynthesis, in the lipid and nucleotide metabolism and several glycolytic and pyruvate catabolism enzymes. Differences in the level of metabolic end-products of the sugar catabolism were found between the strains 200 and 200+. A decrease in the adhesion of both strains to the intestinal cell line was detected in the presence of bile. In simulated gastric and intestinal juices, a protective effect was exerted by milk improving the survival of both microorganisms. These results indicate that bile tolerance in L. delbrueckii subsp. lactis involves several mechanisms responding to the deleterious impact of bile salts on bacterial physiology.

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Andrea Quiberoni

National Scientific and Technical Research Council

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Gabriel Vinderola

National Scientific and Technical Research Council

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Ana Binetti

National Scientific and Technical Research Council

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Viviana Suárez

National Scientific and Technical Research Council

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Daniela M. Guglielmotti

National Scientific and Technical Research Council

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Patricia Burns

Spanish National Research Council

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Giorgio Giraffa

Consiglio per la ricerca e la sperimentazione in agricoltura

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Mariángeles Briggiler Marcó

National Scientific and Technical Research Council

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