Utilization of ram horn hydrolysate as a supplement for recovery of heat- and freeze-injured bacteria

Kurbanoğlu, Esabı Başaran; Algur, Ömer Faruk

doi:10.1016/j.foodcont.2004.11.001

Cited by 11 publications

(2 citation statements)

References 25 publications

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“…This study evaluated the formation of sublethally injured pathogenic cells after the cells were treated with different concentrations of NEO water. It has been reported that sublethally injured bacteria become sensitive to agents to which they would otherwise be resistant (50,51). The presence of a variety of selective ingredients, such as novobiocin and bile salts, in the selective agar can be harmful to injured cells, leading to the retarded growth of injured cells (28,52,53).…”

Section: Discussionmentioning

confidence: 99%

Formation of Sublethally Injured Yersinia enterocolitica, Escherichia coli O157:H7, and Salmonella enterica Serovar Enteritidis Cells after Neutral Electrolyzed Oxidizing Water Treatments

Han

Hung

Bratcher

et al. 2018

Appl Environ Microbiol

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The impact of neutral electrolyzed oxidizing (NEO) water treatments on the formation of sublethally injured , O157:H7, and serovar Enteritidis cells was evaluated. When pathogens were treated with 6% NEO water, approximately 38% of the treated population and 25% of the treated population became sublethally injured. The highest sublethally injured population was found when cultures were treated with 3% NEO water. Regardless of the NEO water concentration used, no sublethally injured O157:H7 cells were found. To evaluate the sensitivity of NEO water-treated cells, four additional stresses (heat treatment, pH, NaCl, and bile salt) were tested. NEO water treatments did not generate any cross protection of treated cells against the other stresses. The diluted NEO water treatments in combination with heat treatment at 51°C for 10 min led to the best synergistic antimicrobial effects with a combined reduction of 7 logs. The gene expression results showed that NEO water treatments led to the upregulation of, , and These genes are known for their involvement in cells' environmental stress responses. In summary, this study investigated the sublethal injury in pathogenic cells caused by NEO water treatments. Although sublethal injury was discovered, when combined with other mild stresses, the synergistic antimicrobial effects were able to further reduce the numbers of viable pathogenic cells. These results demonstrate the great application potential of NEO water as a nonthermal and less corrosive antimicrobial treatment. Neutral electrolyzed oxidizing (NEO) water is a nonthermal and less corrosive antimicrobial treatment that has been demonstrated to have efficacy in reducing microbial contamination in food, including meat, fresh fruit, and vegetables. However, NEO water treatments can cause sublethal injury to pathogenic cells, resulting in cells that retain their viability. Consequently, these sublethally injured pathogenic cells become a serious food safety concern. This study evaluated the formation of sublethally injured , O157:H7, and serovar Enteritidis cells by NEO water treatments and the potential cross protection against heat, pH, NaCl, or bile salt stresses that it may generate. No cross protection was observed. By combining NEO water treatments with sublethal levels of additional stresses, significant synergistic antimicrobial outcomes were achieved. These results indicate that mild processing treatments, when combined, can effectively reduce pathogen populations while minimizing the negative impacts on food quality.

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Section: Discussionmentioning

confidence: 99%

Formation of Sublethally Injured Yersinia enterocolitica, Escherichia coli O157:H7, and Salmonella enterica Serovar Enteritidis Cells after Neutral Electrolyzed Oxidizing Water Treatments

Han

Hung

Bratcher

et al. 2018

Appl Environ Microbiol

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“…Inóculo prévio ao teste obtido em TSA + sanificante (continua) Tubos em cada série Repetição Dias de exposição Nesse caso, em uma única repetição, houve a revelação da aquisição de resistência, pois ocorreu crescimento do B. cereus no tubo de número 7, como pode ser observado na Tabela 12, sendo que anteriormente isso não ocorria (Tabelas 10 e 11). Uma hipótese é que a passagem por um meio capaz de recuperar a injúria do sanificante, tornou a bactéria capaz de suportar e se multiplicar em uma concentração que anteriormente era letal (KURBANOGLU;ALGUR, 2006).…”

Section: Avaliação Da Aquisição De Resistência Da Cepa Exposta a Concunclassified

Estudo de biofilmes e células planctônicas de Bacillus cereus frente a um sanificante à base de composto de quaternário de amônio utilizado na indústria de laticínios

Rossi¹

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Study of Bacillus cereus biofilmes and planktonic cells front to a quaternary ammonium based sanitizer used in the dairy industry Bacillus cereus is a pathogen widely distributed in the environment and a serious problem in the dairy industry because of its ability to form heat-resistant spores that can survive pasteurization and UHT treatments. This bacteria is responsible for foodborne diseases in man due to production of toxins that may cause gastroenteritis, diarrhoea and vomiting. In addition, B. cereus is responsible for spoilage of pasteurized milk and cream referred to as "sweet curdling". Bacillus strains are frequently isolated from pasteurized and UHT treated milk and evidence indicates that biofilm formed on processing equipment surfaces are major sources of milk contamination. In biofilms, adherent cells and spores acquire increased resistance and persist to the sanitization process, becoming sources of bacteria dissemination in food processing. The extracellular polymeric matrix neutralizes the sanitizing agents and exposing the bacteria in biofilms to sublethal concentrations can lead to an increased resistance. In this study, biofilms of B. cereus vegetative cells were developed in a 304 stainless steel (SS) surface with a milk conditioning film. The mean adhesion of cells on SS surface was 1.4 x 10 5 CFU/cm 2. Biofilms of B. cereus spores were also developed, and the mean adhesion found was 1.4 x 10 4 CFU/cm 2. The resistance of B. cereus vegetative cells and spores in biofilms to a simulated clean-in-place (CIP) procedure used in dairy industry was evaluated. After cleaning procedure, the population of vegetative cells in the SS surface was reduced to approximated 1 CFU/cm 2. After sanitizing procedure, the cell count remained unaltered. The remaining contamination was related with the increased resistance of cells in the developed biofilms. After cleaning and sanitizing procedures, the mean of spore adhesion found was 8.9 x 10 1 CFU/cm 2 and 3.3 x 10 1 CFU/cm 2 , respectively. These results show that B. cereus spores are more difficult to remove from SS surfaces than vegetative cells using CIP procedures. Finally, B. cereus vegetative cells were exposed to three different sublethal concentrations (3.9; 1.8 and 0.9µg/mL) of alkyl amidopropyl dimethyl benzyl ammoniun cloride, for evaluation of adaptation, using the Minimum Inhibitory Concentration (MIC) test. The acquired resistance was evaluated by comparing the initial MIC value (7.4µg/mL) with final MICs, after 28 days of exposure. After the adaptation period, with exception of an experiment where the MIC was threefold the original value (29.8µg/mL), in the other experiments the MICs found was double (14.9µg/mL) of the original MIC, indicating acquisition of resistance by the B. cereus strain. It was observed that the growth of cells in the mildest sublethal concentration (0.9µg/mL) resulted in more consistent effects, suggesting that the exposure to mildest sublethal concentrations results in higher adaptive responses.

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Production of 3,4-dihydroxy phenyl-l-alanine (l-DOPA) by Egyptian halophilic black yeast

Mahmoud

El-Bendary²

2010

World J Microbiol Biotechnol

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Production of 3,4-dihydroxy phenyl-L-alanine (L-DOPA) using an Egyptian isolate of halophilic black yeast was studied. Optimum aeration level and incubation period for high yield production of L-DOPA were 50 ml medium/250 ml flask with 200 rpm and 36 h, respectively. Two new techniques (addition of aniline or NaCl to the medium) have been investigated to enhance the monophenolase activity and inhibit or reduce diphenolase activity of tyrosinase to form high yield of L-DOPA without more oxidation to melanin. Addition of aniline to tyrosine medium at 3 ll/ml medium enhanced L-DOPA production 2.9 fold, however, addition of NaCl at 20% showed the same amount of L-DOPA as the control. Peptone and ram horn hydrolysate were studied as nitrogen sources instead of tyrosine in the medium and they showed good nitrogen sources for L-DOPA production as tyrosine. Finally, addition of aniline (3 ll/ml) to ram horn hydrolysate was economically feasible and cost effective for L-DOPA production by Egyptian halophilic black yeast.

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Utilization of ram horn hydrolysate as a supplement for recovery of heat- and freeze-injured bacteria

Cited by 11 publications

References 25 publications

Formation of Sublethally Injured Yersinia enterocolitica, Escherichia coli O157:H7, and Salmonella enterica Serovar Enteritidis Cells after Neutral Electrolyzed Oxidizing Water Treatments

Formation of Sublethally Injured Yersinia enterocolitica, Escherichia coli O157:H7, and Salmonella enterica Serovar Enteritidis Cells after Neutral Electrolyzed Oxidizing Water Treatments

Estudo de biofilmes e células planctônicas de Bacillus cereus frente a um sanificante à base de composto de quaternário de amônio utilizado na indústria de laticínios

Production of 3,4-dihydroxy phenyl-l-alanine (l-DOPA) by Egyptian halophilic black yeast

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