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Beef Samples (beef + sample)
Selected AbstractsINACTIVATION OF BACTERIAL SPORES BY COMBINED ACTION OF HYDROSTATIC PRESSURE AND BACTERIOCINS IN ROAST BEEFJOURNAL OF FOOD SAFETY, Issue 4 2003N. KALCHAYANAND ABSTRACT Foodborne bacterial spores are normally resistant to high hydrostatic pressure; however, at moderate pressure, they can be induced to germinate and outgrow. At this stage, they can be killed by bacteriocin-based biopreservatives (BP-containing pediocin and nisin at 3:7 ratio; BPX, BP + 100 ,g/mL lysozyme; BPY, BPX+ 500 ,g/mL Na-EDTA). Based on this principle, spores of the meat spoilage organism, Clostridium laramie (1,2 × 102 spores/bag) alone or a mixture of four clostridial spores (5 × 103 spores/bag), Clostridium sporogenes, Clostridium perfringens, Clostridium tertium, and Clostridium laramie, were inoculated in roast beef in the presence of 5000 AU/g of bacteriocin-based biopreservatives. The roast beef samples were subjected to hydrostatic pressure (HP) at 345 MPa for 5 min at 60C and stored at 4 or 12C for 84 days or at 25C for 7 days. The HP treatment of roast beef samples inoculated with a mixture of clostridial spores could be stored for 42 days at 4C. The HP in combination with either BPX or BPY extended the shelf-life of roast beef up to 7 days at 25C. The combined treatment of HP and BP controlled the growth of C. laramie spores and extended the shelf-life of roast beef for 84 days when stored at 4C. [source] Evaluation of Antioxidant Effects of Raisin Paste in Cooked Ground Beef, Pork, and ChickenJOURNAL OF FOOD SCIENCE, Issue 4 2006M.N. Vasavada ABSTRACT:, The objective of this study was to evaluate the possible antioxidant activity of raisin paste added to raw ground beef, pork, or chicken before cooking to 163 °C. Samples were held at 2 °C for up to 14 d. TBA values were measured using a distillation method, to avoid yellow color interference found in "wet" TBA methods. Sample meat flavor intensity, rancid flavor intensity, and raisin flavor intensity were evaluated by a trained panel (n = 6). Addition of raisin paste lowered (p < 0.05) TBA values and decreased panel scores for rancid flavor scores of all meat samples in a concentration-dependent manner. Highest antioxidant effects were obtained with a minimum of 1.5%, 2.0%, or 2.0% raisin paste in cooked ground beef, pork, or chicken, respectively. There was a high correlation (0.93, 0.94, 0.94) between TBA values and sensory rancid flavor scores in beef, pork, and chicken samples respectively. Addition of a reducing sugar (glucose) was nearly as effective as raisins for maintenance of low TBA values and rancid flavor scores, probably due to antioxidant effects of Maillard browning products. There was no detectable raisin flavor in cooked ground beef samples with added raisins. However, all meats with added glucose had a higher raisin flavor intensity score than controls, indicating that panelists associated sweetness with raisin flavor. Maillard browning (sample darkening) was evident after cooking of ground chicken with either raisins or glucose. [source] Evaluation of Milk Mineral Antioxidant Activity in Beef Meatballs and Nitrite-cured SausageJOURNAL OF FOOD SCIENCE, Issue 4 2005Mihir N. Vasavada ABSTRACT: The objective of this study was to determine the antioxidant activity of 1.5% milk mineral (MM) added to uncured cooked beef meatballs and to evaluate possible synergistic effects of MM in combination with 20-ppm or 40-ppm sodium nitrite in beef sausages. All treatments were also formulated with 1.5% salt and 10% added water. Thiobarbituric acid (TBA) values and Hunter color values were determined at 1 d, 8 d, and 15 d of storage at 2°C. Meatball cooked yield was also measured. Cooked yield was not different (P < 0.05) between control meatballs and those containing MM. As expected, treatments containing nitrite had higher redness (CIE a*) than samples without nitrite. Redness values increased with storage time in sausages containing 40-ppm nitrite. However, redness values decreased (P < 0.05) during storage for control meatballs, associated with increased lipid oxidation (higher TBA values). Lipid oxidation was lower (P < 0.05) in samples containing 1.5% MM with TBA values <1.2 after 15 d of storage compared with 6.1 for control samples. There was no synergistic inhibition of lipid oxidation in samples containing 20-ppm or 40-ppm sodium nitrite plus 1.5% MM. Milk mineral alone at 1.5% of meat weight was sufficient for inhibition of lipid oxidation in cooked beef samples. [source] Immunoliposomes Sandwich Fluorometric Assay (ILSF) for Detection of Escherichia coli O157:H7JOURNAL OF FOOD SCIENCE, Issue 6 2004Sungsu Park ABSTRACT: We report the development of automated flourometric immunoassay for the detection of Escherichia coli O157:H7, using antibody-directed liposomes (immunoliposomes) encapsulating fluorophore as an analytical reagent. Thiolated antibodies (anti- E. coli O157:H7) were coupled to malemide-tagged liposomes encapsulating dye. To automate the assay, a fluorescence plate reader was included in the assay system to detect fluorophore released from lysed liposomes in a microplate. The detection limit of the current assay with pure cultures of the serotype was about 104 colony-forming units (CFU)/mL. The assay can detect E. coli O157 in ground beef samples inoculated with as few as 0.8 CFU/mL after a 12-h enrichment. These results demonstrate the feasibility of using fluorophore-encapsulated immunoliposomes in a microtiter plate for the rapid and automated detection of molecules with multivalent antigenic sites. [source] Effect of selected antimicrobial compounds on the radiosensitization of Salmonella Typhi in ground beefLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2009M. Turgis Abstract Aims:, In this study, we extended our previous work to determine the efficiency of antimicrobial compounds in increase of relative radiosensitivity of Salmonella Typhi in medium fat ground beef (23% fat) by testing 41 different essential oils (EOs), oleoresins and food sauces. Methods and Results:, Ground beef samples inoculated with Salmonella Typhi (106 CFU g,1) were treated with each antimicrobial compound at a concentration of 0·5% (w/w). Then, the samples (25 g each) were packaged under air and irradiated in a 60Co irradiator at doses from 0 to 1·75 kGy. Radiosensitivity was evaluated by calculating relative radiation sensitivity, defined as the ratio of radiation D10 value in the absence/presence of antimicrobial compound. Conclusions:, Depending on the compound tested, the addition of antimicrobial compound decreased the D10 value of Salmonella Typhi, resulting in an increase of the radiation sensitivity up to more than four times. Among these antimicrobial compounds, Chinese cinnamon EO, clove EO and trans -cinnamaldehyde were most effective to increase the radiosensitivity of Salmonella Typhi in ground beef. Significance and Impact of the Study:, These observations demonstrate that some active compounds can function as radiosensitizers of Salmonella Typhi. [source] Detection, isolation and characterization of Shiga toxin-producing Escherichia coli in retail-minced beef using PCR-based techniques, immunoassays and colony hybridizationLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2007F. Auvray Abstract Aims:, To provide information on detection of Shiga toxin-producing Escherichia coli (STEC) in retail-minced beef using an approach combining (i) PCR-based techniques and automated immunoassay for stx screening and detection of the five major serogroups associated with human infection, and (ii) immunomagnetic separation (IMS) and colony hybridization assays for bacterial strain isolation. Methods and Results:, Twenty-seven out of 164 minced beef samples were stx -positive by PCR-ELISA, nine of which were also positive by real-time PCR for at least one marker of the five main serogroups tested (O26, O103, O111, O145 and O157). Two E. coli O103 stx -negative strains were isolated from two out of 10 IMS and nine STEC strains that did not belong to the five main serogroups were isolated by colony hybridization. Conclusions:, PCR techniques are applicable for rapid screening of samples containing both an stx gene and an O-group marker of the five main pathogenic STEC serogroups. Isolation of STEC strains belonging to the main non-O157 serogroups remains difficult. Significance and Impact of the Study:, This study presents an evaluation of a multi-faceted approach for the detection of the most frequently reported human pathogenic STEC serogroups. The advantages and limits of this strategy are presented. [source] Prevalence of Escherichia coli O157:H7 in industrial minced beefLETTERS IN APPLIED MICROBIOLOGY, Issue 1 2002C. Vernozy-Rozand Aims: ,The lack of baseline data on the prevalence of Escherichia coli O157:H7 in retail minced beef in France prompted this survey of industrial minced beef production. Methods and Results: ,An automated enzyme-linked fluorescence immunoassay (ELFA), the VIDAS E. coli O157 method, was used to detect E. coli O157 in industrial minced beef samples. Confirmation of samples positive according to the ELFA was performed using an automated immunoconcentration (ICE) system, VIDAS ICE, which allows the selective capture and release of target organisms. The ICE was followed by culture on cefixime tellurite sorbitol MacConkey agar and a chromogenic medium, O157:H7 ID. Of the 3450 minced beef samples tested, 175 samples were positive with the ELFA method and, of these, four were confirmed by the ICE method. They were identified as sorbitol-negative, O157-positive, H7-positive, mobile, verotoxin-producing E. coli . Conclusions: ,The prevalence of E. coli O157:H7 in industrial French minced beef was 0·12%, consistent with many other reports. Significance and Impact of the Study: ,The low infective dose of E. coli O157:H7 presents a major threat. The main means of combating this organism are thermal destruction and good food hygiene covering activities on-farm, in the abattoir and in minced beef industries. [source] | ||||||||||