Institute of Technology of Agricultural Products

Athens, Greece

Institute of Technology of Agricultural Products

Athens, Greece

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Gkana E.,Agricultural University of Athens | Chorianopoulos N.,Institute of Technology of Agricultural Products | Grounta A.,Agricultural University of Athens | Koutsoumanis K.,Aristotle University of Thessaloniki | Nychas G.-J.E.,Agricultural University of Athens
Food Microbiology | Year: 2017

The objective of the present study was to determine the factors affecting the transfer of foodborne pathogens from inoculated beef fillets to non-inoculated ones, through food processing surfaces. Three different levels of inoculation of beef fillets surface were prepared: a high one of approximately 107 CFU/cm2, a medium one of 105 CFU/cm2 and a low one of 103 CFU/cm2, using mixed-strains of Listeria monocytogenes, or Salmonella enterica Typhimurium, or Escherichia coli O157:H7. The inoculated fillets were then placed on 3 different types of surfaces (stainless steel-SS, polyethylene-PE and wood-WD), for 1 or 15 min. Subsequently, these fillets were removed from the cutting boards and six sequential non-inoculated fillets were placed on the same surfaces for the same period of time. All non-inoculated fillets were contaminated with a progressive reduction trend of each pathogen's population level from the inoculated fillets to the sixth non-inoculated ones that got in contact with the surfaces, and regardless the initial inoculum, a reduction of approximately 2 log CFU/g between inoculated and 1st non-inoculated fillet was observed. S. Typhimurium was transferred at lower mean population (2.39 log CFU/g) to contaminated fillets than E. coli O157:H7 (2.93 log CFU/g), followed by L. monocytogenes (3.12 log CFU/g; P < 0.05). Wooden surfaces (2.77 log CFU/g) enhanced the transfer of bacteria to subsequent fillets compared to other materials (2.66 log CFU/g for SS and PE; P < 0.05). Cross-contamination between meat and surfaces is a multifactorial process strongly depended on the species, initial contamination level, kind of surface, contact time and the number of subsequent fillet, according to analysis of variance. Thus, quantifying the cross-contamination risk associated with various steps of meat processing and food establishments or households can provide a scientific basis for risk management of such products. © 2016 Elsevier Ltd


Papadopoulou O.S.,Institute of Technology of Agricultural Products | Chorianopoulos N.G.,Institute of Technology of Agricultural Products
Current Research in Nutrition and Food Science | Year: 2016

The aim of the study was the production of fresh cheese with enhanced quality, standardized characteristics and increased functional and nutritional value. The main idea was to produce probiotic cheese with the use of probiotic bacteria isolated from the microflora of traditional Greek products. For this reason, fresh cheese was produced according to the traditional method (control) and the probiotic strain Lb. plantarum T571 was also added as co-culture (probiotic). All samples were inoculated with L. monocytogenes (3 strains) of 3 log CFU/g initial inoculum level. Microbiological analysis occured during cheese production and until the end of the shelf life of the product stored at 4°C under vacuum packaging. pH, water activity (aW) and titratable acidity were also monitored along with the sensory analysis of the product. The survival of probiotic and Listeria strains was assessed by Pulsed Field Gel Electrophoresis (PFGE). Results showed that on the 1st day of manufacture the population levels of lab exceeded 8 log CFU/g for all inoculated samples. By the end of shelf life, the population levels of lab in probiotic samples were approximately 7.5 log CFU/g. However, the probiotic samples resulted to significantly higher acidity, lower pH and reduced counts of coliforms and Listeria spp. The quality characteristics of probiotic products compared with the control ones were better according to the test panel. Regarding the PFGE results, Lb. plantarum T571 strain was found in all cases at populations above 7 log CFU/g. Although further research is needed, the results of the current study were encouraging for producing a probiotic fresh cheese with high added value and increased safety levels. © 2016, Enviro Research Publishers. All rights reserved.


Blana V.A.,Agricultural University of Athens | Polymeneas N.,Agricultural University of Athens | Tassou C.C.,Institute of Technology of Agricultural Products | Panagou E.Z.,Agricultural University of Athens
Food Microbiology | Year: 2016

The survival of selected lactic acid bacteria (LAB) with in vitro probiotic potential was studied during storage of cv. Halkidiki green olives previously subjected to inoculated Spanish-style fermentation. After fermentation olives were packed in polyethylene pouches, covered with freshly prepared brine (9%, w/v, NaCl), acidified with 2‰ (w/v) citric acid and 1.5‰ (w/v) ascorbic acid, and stored at 4 and 20 °C for 357 days. Four packing treatments were studied, namely olives previously fermented by (i) the indigenous microbiota (control); (ii) Lactobacillus pentosus B281; (iii) Lactobacillus plantarum B282; and (iv) a co-culture of both LAB strains. Microbiological analyses were performed on the olives in parallel with physicochemical changes (pH, titratable acidity, salt content, aw and colour) at the early (day 1), middle (day 197) and final stage (day 357) of storage, as well as sensory evaluation at the end of the storage. The survival of probiotic strains was confirmed by Pulsed Field Gel Electrophoresis (PFGE). LAB decreased throughout storage reaching a final population of ca. 3.5-4.0 log CFU/g and 4.5-5.0 log CFU/g at 4 and 20 °C, respectively. The pH values ranged between 3.90 and 4.61 during storage depending on packaging condition. PFGE analysis revealed that L. pentosus B281 and L. plantarum B282 showed a high survival rate with a recovery of 100 and 96%, respectively, at 4 °C, and less than 20% for both strains at 20 °C. Finally, in the packing treatment with a co-culture of both strains, L. pentosus dominated over L. plantarum throughout storage at both temperatures. © 2015 Elsevier Ltd.


Argyri A.A.,Institute of Technology of Agricultural Products | Zoumpopoulou G.,Agricultural University of Athens | Karatzas K.A.G.,University of Reading | Tsakalidou E.,Agricultural University of Athens | And 3 more authors.
Food Microbiology | Year: 2013

The present study aims to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from naturally fermented olives and select candidates to be used as probiotic starters for the improvement of the traditional fermentation process and the production of newly added value functional foods. Seventy one (71) lactic acid bacterial strains (17 Leuconostoc mesenteroides, 1 Ln. pseudomesenteroides, 13 Lactobacillus plantarum, 37 Lb. pentosus, 1 Lb. paraplantarum, and 2 Lb. paracasei subsp. paracasei) isolated from table olives were screened for their probiotic potential. Lb. rhamnosus GG and Lb. casei Shirota were used as reference strains. The in vitro tests included survival in simulated gastrointestinal tract conditions, antimicrobial activity (against Listeria monocytogenes, Salmonella Enteritidis., Escherichia coli O157:H7), Caco-2 surface adhesion, resistance to 9 antibiotics and haemolytic activity. Three (3) Lb. pentosus, 4 Lb. plantarum and 2 Lb. paracasei subsp. paracasei strains demonstrated the highest final population (>8 log cfu/ml) after 3 h of exposure at low pH. The majority of the tested strains were resistant to bile salts even after 4 h of exposure, while 5 Lb. plantarum and 7 Lb. pentosus strains exhibited partial bile salt hydrolase activity. None of the strains inhibited the growth of the pathogens tested. Variable efficiency to adhere to Caco-2 cells was observed. This was the same regarding strains' susceptibility towards different antibiotics. None of the strains exhibited β-haemolytic activity. As a whole, 4 strains of Lb. pentosus, 3 strains of Lb. plantarum and 2 strains of Lb. paracasei subsp. paracasei were found to possess desirable in vitro probiotic properties similar to or even better than the reference probiotic strains Lb. casei Shirota and Lb. rhamnosus GG. These strains are good candidates for further investigation both with in vivo studies to elucidate their potential health benefits and in olive fermentation processes to assess their technological performance as novel probiotic starters. © 2012 Elsevier Ltd.


Argyri A.A.,Institute of Technology of Agricultural Products | Nisiotou A.A.,Institute of Technology of Agricultural Products | Mallouchos A.,Agricultural University of Athens | Panagou E.Z.,Agricultural University of Athens | Tassou C.C.,Institute of Technology of Agricultural Products
International Journal of Food Microbiology | Year: 2014

The performance of two potential probiotic Lactobacillus strains from olive microbiota, namely L. pentosus B281 and L. plantarum B282 was assessed as starter cultures in Spanish-style fermentation of heat shocked green olives cv. Halkidiki. Two different initial salt levels were studied, 10% (w/v) and 8% (w/v) NaCl, and the brines were inoculated with (a) L. pentosus B281, (b) L. plantarum B282, and (c) a mixture of both strains. A spontaneous fermentation was also taken into account as control treatment. Prior to brining, olives were heat shocked at 80. °C for 10. min to reduce the level of the indigenous microbiota on olive drupes and facilitate the dominance of the inoculated cultures. Microbiological, physicochemical and sensory analyses were conducted throughout fermentation. The composition of LAB population and the evolution of added inocula were assessed by Pulsed Field Gel Electrophoresis (PFGE). The final population of LAB was maintained above 6. log cycles in olive flesh. Both L. pentosus B281 and L. plantarum B282 were able to dominate over indigenous LAB, albeit strain B281 exhibited higher recovery percentages (100 or 94.7% for B281 and 58.8% or 55.0% for B282 in 10% or 8% NaCl, respectively). L. pentosus B281 also dominated over L. plantarum B282, when the two strains were co-inoculated in olive fermentations. The sensory assessment showed higher preference for inoculated fermentations of L. pentosus and L. plantarum separately in 8% NaCl, followed by the L. plantarum in 10% NaCl. The present study showed that probiotic strains L. pentosus B281 and L. plantarum B282, may offer a great potential for use as functional starter cultures in olive fermentation and deliver a promising probiotic food to the consumer. © 2013 Elsevier B.V.


Doulgeraki A.I.,Agricultural University of Athens | Pramateftaki P.,Institute of Technology of Agricultural Products | Argyri A.A.,Institute of Technology of Agricultural Products | Nychas G.J.E.,Agricultural University of Athens | And 2 more authors.
LWT - Food Science and Technology | Year: 2013

A total of 145 lactic acid bacteria (LAB) isolates have been recovered from fermented table olives and brine and characterized at strain level with molecular tools. Pulsed-Field Gel Electrophoresis (PFGE) of ApaI macrorestriction fragments was applied for strain differentiation. Species differentiation was based either on Denaturing Gradient Gel Electrophoresis (PCR-DGGE) (black olives) or on restriction analysis of the amplified 16S rRNA gene (PCR-ARDRA) (brine and green olives). Species identification was based on sequence analysis of 16S rRNA gene. When the data were insufficient to resolve the species level of the isolates, specific multiplex PCR assays targeting the recA or tuf genes were employed. From 145 LAB isolates, 71 different strains were recovered from fermented olive and brine samples; 17 strains were assigned to Leuconostoc mesenteroides, 51 were grouped in Lactobacillus plantarum group (including 13 L. plantarum, 37 Lactobacillus pentosus, 1 Lactobacillus paraplantarum), 2 Lactobacillus paracasei subsp. paracasei and 1 Leuconostoc pseudomesenteroides. L. plantarum was recovered mainly from green olive fermentation, whereas in black olives the main species identified were L. pentosus and Ln. mesenteroides). These observations reveal that olives are a highly diverse ecosystem regarding the presence of LAB, which may affect the quality of the final fermented product. © 2012 Elsevier Ltd.


Blana V.A.,Agricultural University of Athens | Grounta A.,Agricultural University of Athens | Tassou C.C.,Institute of Technology of Agricultural Products | Nychas G.J.E.,Agricultural University of Athens | Panagou E.Z.,Agricultural University of Athens
Food Microbiology | Year: 2014

The performance of two strains of lactic acid bacteria (LAB), namely Lactobacillus pentosus B281 and Lactobacillus plantarum B282, previously isolated from industrially fermented table olives and screened invitro for probiotic potential, was investigated as starter cultures in Spanish style fermentation of cv. Halkidiki green olives. Fermentation was undertaken at room temperature in two different initial salt concentrations (8% and 10%, w/v, NaCl) in the brines. The strains were inoculated as single and combined cultures and the dynamics of their population on the surface of olives was monitored for a period of 114 days. The survival of inoculated strains on olives was determined using Pulsed Field Gel Electrophoresis (PFGE). Both probiotic strains successfully colonized the olive surface at populations ranged from 6.0 to 7.0logCFU/g throughout fermentation. PFGE analysis revealed that L.pentosus B281 presented higher colonization in both salt levels at the end of fermentation (81.2% and 93.3% in 8% and 10% NaCl brines, respectively). For L.plantarum B282 a high survival rate (83.3%) was observed in 8% NaCl brines, but in 10% NaCl the strain could not colonize the surface of olives. L.pentosus B281 also dominated over L.plantarum B282 in inoculated fermentations when the two strains were used as combined culture. The biochemical profile (pH, organic acids, volatile compounds) attained during fermentation and the sensory analysis of the final product indicated a typical lactic acid fermentation process of green olives. © 2013 Elsevier Ltd.


Argyri A.A.,Institute of Technology of Agricultural Products | Lyra E.,Institute of Technology of Agricultural Products | Panagou E.Z.,Agricultural University of Athens | Tassou C.C.,Institute of Technology of Agricultural Products
Food Microbiology | Year: 2013

The survival of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes during the storage of fermented green table olives cv. Halkidiki in brine was studied in parallel with the evolution of lactic acid bacteria (LAB), yeasts and pH. The olives were previously fermented with a starter culture (a potential probiotic strain of Lactobacillus pentosus B281 - starter process) or with the indigenous microbiota (control). After the end of fermentation, olives were placed in brine, inoculated with a cocktail of 5 strains of E.coli O157:H7, 5 strains of L.monocytogenes and 4 strains of S. Enteritidis, with a final concentration in the brine of ca. 7.0 log CFU/ml, and subsequently packaged in polyethylene pouches and stored at 20°C. The population of E.coli O157:H7 reduced gradually and was detected in the brine until the 27th day of storage in both cases (i.e., starter and control process), and on olive fruits until the 19th and 16th days of storage in the starter and control process, respectively. S. Enteritidis population showed also a decrease and it was detected until the 21st day of storage in both brine and olive fruits in both cases. The population of L.monocytogenes declined during storage and it was detected until the 31st day of storage in both brine and olive fruits in both cases, showing a longer survival period in comparison to the other two studied pathogens. The presence of the potential probiotic starter did not affect the pathogen survival. The results demonstrated that even though the growth of the pathogenic strains was not supported, they may survive for a long period in a stressful environment of a fermented product with low pH value (4.2) and high salt concentration (6.0%). These results are a valuable contribution to risk assessment studies related to ready to eat foods in general. © 2013 Elsevier Ltd.


Argyri A.A.,Agricultural University of Athens | Argyri A.A.,Institute of Technology of Agricultural Products | Mallouchos A.,Agricultural University of Athens | Panagou E.Z.,Agricultural University of Athens | Nychas G.J.E.,Agricultural University of Athens
International Journal of Food Microbiology | Year: 2015

The aim of the current study was to assess meat spoilage through the evolution of volatile compounds using chemometrics. Microbiological and sensory assessment, pH measurement and headspace solid phase microextraction gas chromatography/mass spectroscopy (headspace SPME-GC/MS) analysis were carried out in minced beef stored aerobically and under modified atmosphere packaging (MAP) at 0, 5, 10, and 15. °C. It was shown that the HS/SPME-GC/MS analysis provided useful information about a great number of volatile metabolic compounds detected during meat storage. Many of the identified and semi-quantified compounds were correlated with the sensory scores through the use of chemometrics, depicting possible spoilage indicators such as 2-pentanone, 2-nonanone, 2-methyl-1-butanol, 3-methyl-1-butanol, ethyl hexanoate, ethyl propanoate, ethyl lactate, ethyl acetate, ethanol, 2-heptanone, 3-octanone, diacetyl, and acetoin. Finally, the applied GC/MS global models were able to estimate the microbial counts of the different microorganisms and the sensory scores of a meat sample regardless of storage conditions (i.e. packaging and temperature). © 2014 Elsevier B.V.


Dissing B.S.,Technical University of Denmark | Papadopoulou O.S.,Agricultural University of Athens | Papadopoulou O.S.,Institute of Technology of Agricultural Products | Tassou C.,Institute of Technology of Agricultural Products | And 4 more authors.
Food and Bioprocess Technology | Year: 2013

The quality of stored minced pork meat was monitored using a rapid multispectral imaging device to quantify the degree of spoilage. Bacterial counts of a total of 155 meat samples stored for up to 580 h have been measured using conventional laboratory methods. Meat samples were maintained under two different storage conditions: aerobic and modified atmosphere packages as well as under different temperatures. Besides bacterial counts, a sensory panel has judged the spoilage degree of all meat samples into one of three classes. Results showed that the multispectral imaging device was able to classify 76.13 % of the meat samples correctly according to the defined sensory scale. Furthermore, the multispectral camera device was able to predict total viable counts with a standard error of prediction of 7.47 %. It is concluded that there is a good possibility that a setup like the one investigated will be successful for the detection of spoilage degree in minced pork meat. © 2012 Springer Science+Business Media, LLC.

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