Food Poisoning Potential of Pathogens Inoculated onto Bologna in Sandwiches1

1978 ◽  
Vol 41 (12) ◽  
pp. 953-956 ◽  
Author(s):  
D. C. PARADIS ◽  
M. E. STILES
Keyword(s):  
Food Poisoning ◽  
Food Service ◽  
Low Ph ◽  
Enteropathogenic Escherichia Coli ◽  
Experimental Conditions ◽  
Gram Negative ◽  
Significant Growth ◽  
Bacterial Competition ◽  
Low Levels ◽  
And Storage

Bologna sandwiches inoculated separately with low levels (100 to 1000 per g) of specific pathogens at time of sandwich preparation to simulate conditions that might occur in home or food service preparation, were stored at 4, 21 and 30 C for 0, 4, 8 and 25 h and monitored for growth of pathogens. All pathogens, except Clostridium perfringens, were capable of significant growth after more than 8 h of incubation at 30 C, but not at 4 or 21 C. Significant growth at 21 C only occurred with Staphylococcus aureus after 25 h of incubation. C. perfringens failed to grow on bologna in all sandwiches. All other pathogens, except S. aureus, failed to grow on bologna with low pH (pH <6.1). Growth of S. aureus, was retarded on bologna at pH 5.5, and inhibited at pH 5.1. Only gram negative pathogens (enteropathogenic Escherichia coli and Salmonella typhimurium) were adversely affected by increased bacterial competition. Results indicated that bologna in sandwiches under these experimental conditions would only become a potential vehicle for food poisoning under almost unrealistic conditions of handling and storage.

scholarly journals The Lipid Lysyl-Phosphatidylglycerol Is Present in Membranes of Rhizobium tropici CIAT899 and Confers Increased Resistance to Polymyxin B Under Acidic Growth Conditions

2007 ◽  
Vol 20 (11) ◽  
pp. 1421-1430 ◽  
Author(s):  
Christian Sohlenkamp ◽  
Kanaan A. Galindo-Lagunas ◽  
Ziqiang Guan ◽  
Pablo Vinuesa ◽  
Sally Robinson ◽  
...  
Keyword(s):  
Sinorhizobium Meliloti ◽  
Minimal Medium ◽  
Polymyxin B ◽  
Growth Conditions ◽  
Membrane Lipid ◽  
Low Ph ◽  
Wild Type ◽  
Rhizobium Tropici ◽  
Gram Negative ◽  
Inducible Genes

Lysyl-phosphatidylglycerol (LPG) is a well-known membrane lipid in several gram-positive bacteria but is almost unheard of in gram-negative bacteria. In Staphylococcus aureus, the gene product of mprF is responsible for LPG formation. Low pH-inducible genes, termed lpiA, have been identified in the gram-negative α-proteobacteria Rhizobium tropici and Sinorhizobium medicae in screens for acid-sensitive mutants and they encode homologs of MprF. An analysis of the sequenced bacterial genomes reveals that genes coding for homologs of MprF from S. aureus are present in several classes of organisms throughout the bacterial kingdom. In this study, we show that the expression of lpiA from R. tropici in the heterologous hosts Escherichia coli and Sinorhizobium meliloti causes formation of LPG. A wild-type strain of R. tropici forms LPG (about 1% of the total lipids) when the cells are grown in minimal medium at pH 4.5 but not when grown in minimal medium at neutral pH or in complex tryptone yeast (TY) medium at either pH. LPG biosynthesis does not occur when lpiA is deleted and is restored upon complementation of lpiA-deficient mutants with a functional copy of the lpiA gene. When grown in the low-pH medium, lpiA-deficient rhizobial mutants are over four times more susceptible to the cationic peptide polymyxin B than the wild type.

Postharvest handling of cut immature Eucalyptus foliage

1993 ◽  
Vol 33 (5) ◽  
pp. 663 ◽  
Author(s):  
RB Jones ◽  
JK Truett ◽  
M Hill
Keyword(s):  
Active Chlorine ◽  
Vase Life ◽  
Distilled Water ◽  
Dry Storage ◽  
Wet Storage ◽  
Postharvest Handling ◽  
Low Levels ◽  
Exogenous Ethylene ◽  
Dry Transport ◽  
And Storage

Optimum postharvest and storage treatments were investigated for cut immature branches of Eucalyptus crenulata Blakely & Beuzev. and Eucalyptus gunnii J. D. Hook. The application of the germicide BCDMH at 10 mg/L of active chlorine, 100 �L Agral-600/L. or 0.25% sucrose to vase solutions significantly enhanced vase life in E. crenulata Longevity in E. gunnii was significantly extended by sucrose (0.25-2% w/v), but not by germicides or Agral. Sucrose pulses (1-10% for 24 11 at 20�C) or exogenous ethylene (50 �L/L for 24 h at 20�C) had no effect on the longevity of either species. Both species produced very low levels of ethylene immediately after harvest and after a 24-h simulation of dry transport at 20�C. Longevity was not significantly altered in either species by 35 days of dry storage at 1�C. or by 7 days of wet storage (branches held in distilled water + 50 mg DICAJL) at 1�C, but declined significantly in both species after 7 days of wet storage at 10�C.

scholarly journals Effects of Saline, an Ambient Acidic Environment, and Sodium Salicylate on OXA-Mediated Carbapenem Resistance in Acinetobacter baumannii: TABLE 1

2016 ◽  
Vol 60 (6) ◽  
pp. 3415-3418 ◽  
Author(s):  
Esther Zander ◽  
Harald Seifert ◽  
Paul G. Higgins
Keyword(s):  
Gene Expression ◽  
Acinetobacter Baumannii ◽  
Sodium Salicylate ◽  
Carbapenem Resistance ◽  
Low Ph ◽  
Wild Type ◽  
Experimental Conditions ◽  
Content Type ◽  
Reference Strains

Different physiological conditions, such as NaCl, low pH, and sodium salicylate, have been shown to affect antibiotic resistance determinants inAcinetobacter baumanniiisolates. Therefore, the aim of this study was to investigate the effects of NaCl, sodium salicylate, and low pH on the susceptibility ofA. baumanniito carbapenem. We cloned genes encoding oxacillinases (OXA) of different subclasses, with their associated promoters, from carbapenem-resistantA. baumanniiisolates into the same vector and transferred them to theA. baumanniireference strains ATCC 19606 and ATCC 17978. Carbapenem MICs were determined at least in triplicate by agar dilution under standard conditions, as well as in the presence of 200 mM NaCl or 16 mM sodium salicylate, or at pH 5.8. OXA-58-like gene expression was determined by reverse transcription-quantitative PCR (qRT-PCR). Under some experimental conditions, significant MIC reductions were shown for some transformants but not for others. Only in one instance were all transformants harboring the same OXA affected by the same condition: at pH 5.8, the imipenem and meropenem MICs for strains expressing OXA-58-like enzymes decreased from a resistant level (32 to 64 mg/liter) to an intermediate-susceptible level (8 mg/liter). However,blaOXA-58-likegene expression remained the same. MICs for both wild-type reference strains were not affected by the conditions tested. Our results indicate that the effects of the experimental conditions tested on OXAin vivoare mostly strain dependent. MICs were not reduced to wild-type levels, suggesting that the conditions tested do not lead to complete OXA inhibition in the bacterial cell.

scholarly journals Histamine Level in Freshwater and Marine Fish Sold in Bulgarian Markets

2020 ◽  
Author(s):  
D. Bangieva ◽  
D. Stratev ◽  
T. Stoyanchev
Keyword(s):  
Marine Fish ◽  
Enzyme Linked Immunosorbent Assay ◽  
Fish Farms ◽  
Histamine Concentration ◽  
Microbial Decomposition ◽  
Fish Samples ◽  
Low Levels ◽  
Processing And Storage ◽  
Seafood Processing ◽  
And Storage

Background: Histamine is an essential biogenic amine produced as a result of microbial decomposition of histidine during seafood processing and storage. The objective of this study was to evaluate histamine concentration in freshwater and marine fish marketed in Stara Zagora region, Bulgaria. Methods: Forty fish samples were purchased from local fish farms and retail stores in Stara Zagora, Bulgaria. Enzyme-Linked Immunosorbent Assay was used to determine histamine levels. The data were processed using GraphPad Software InStat 3. Results: Histamine was detected in 26 out of 40 (65%) samples, and none of them exceeded the regulatory limit of 200 mg/kg. The average histamine content in marine fish (6.965±3.187 mg/kg) was insignificantly (p>0.05) higher than that in freshwater fish (4.503±1.133 mg/kg). Conclusion: The results reveal low levels of histamine in freshwater and marine fish indicating their good quality. However, its presence in seafoods remains a major food safety problem that requires permanent regulation of histamine concentration in fish.  

scholarly journals Isolation of newer probiotic microorganisms from unconventional sources

2018 ◽  
Vol 10 (3) ◽  
pp. 847-852
Author(s):  
Manpreet Kaur ◽  
Gaganpreet Kaur ◽  
Amita Sharma
Keyword(s):  
Human Health ◽  
Dairy Products ◽  
Bile Salts ◽  
Food Industry ◽  
Low Ph ◽  
Industrial Scale ◽  
Good Adherence ◽  
Gram Negative ◽  
Probiotic Microbes ◽  
Adherence Ability

Probiotics are live microbes in the form of dried or fermented cells that are highly beneficial for human health. The food industry has been revolutionised due to introduction of potential probiotic organisms in a varied formulations derived from mostly dairy products. Isolation of probiotic microbes from unexplored non-dairy sources is gaining attention these days. In the present study, six potential probiotic isolates from non-dairy sources were obtained that are also biocompatible with each other. Out of these, five isolates were gram positive rod shaped and one was gram negative rod shaped. These isolates were able to grow in presence of lysozyme, low pH and bile salts with good adherence ability. The market for probiotic microorganisms from unconventional products is accelerating to deal with lactose intolerant people. These probiotic attribute studies revealed their potential to be exploited at industrial scale.

scholarly journals Human genetic deficiencies reveal the roles of complement in the inflammatory network: Lessons from nature

2009 ◽  
Vol 106 (37) ◽  
pp. 15861-15866 ◽  
Author(s):  
Knut Tore Lappegård ◽  
Dorte Christiansen ◽  
Anne Pharo ◽  
Ebbe Billmann Thorgersen ◽  
Bernt Christian Hellerud ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Gram Negative Bacteria ◽  
Enzyme Release ◽  
Experimental Conditions ◽  
Gram Negative ◽  
Cytokines And Chemokines ◽  
Ifn Γ ◽  
Inducible Protein ◽  
The Complement System

Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to Gram-negative bacteria were here studied taking advantage of human genetic complement-deficiencies—nature's own knockouts—including a previously undescribed C5 defect. Such deficiencies provide a unique tool for investigating the biological role of proteins. The experimental conditions allowed cross-talk between the different inflammatory pathways using a whole blood model based on the anticoagulant lepirudin, which does not interfere with the complement system. Expression of tissue factor, cell adhesion molecules, and oxidative burst depended highly on C5, mediated through the activation product C5a, whereas granulocyte enzyme release relied mainly on C3 and was C5a-independent. Release of cytokines and chemokines was mediated to varying degrees by complement and CD14; for example, interleukin (IL)-1β and IL-8 were more dependent on complement than IFN-γ and IL-6, which were highly dependent on CD14. IL-1 receptor antagonist (IL-1ra) and IFN-γ inducible protein 10 (IP-10) were fully dependent on CD14 and inversely regulated by complement, that is, complement deficiency and complement inhibition enhanced their release. Granulocyte responses were mainly complement-dependent, whereas monocyte responses were more dependent on CD14. Notably, all responses were abolished by combined neutralization of complement and CD14. The present study provides important insight into the comprehensive role of complement in human inflammatory responses to Gram-negative bacteria.

scholarly journals Bacillus cereus NVH 0500/00 Can Adhere to Mucin but Cannot Produce Enterotoxins during Gastrointestinal Simulation

2015 ◽  
Vol 82 (1) ◽  
pp. 289-296 ◽  
Author(s):  
Varvara Tsilia ◽  
Frederiek-Maarten Kerckhof ◽  
Andreja Rajkovic ◽  
Marc Heyndrickx ◽  
Tom Van de Wiele
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Intestinal Bacteria ◽  
Low Ph ◽  
Final Concentration ◽  
Adhesion Assay ◽  
Content Type ◽  
The Stability ◽  
Bacterial Concentrations

ABSTRACTAdhesion to the intestinal epithelium could constitute an essential mechanism ofBacillus cereuspathogenesis. However, the enterocytes are protected by mucus, a secretion composed mainly of mucin glycoproteins. These may serve as nutrients and sites of adhesion for intestinal bacteria. In this study, the food poisoning bacteriumB. cereusNVH 0500/00 was exposedin vitroto gastrointestinal hurdles prior to evaluation of its attachment to mucin microcosms and its ability to produce nonhemolytic enterotoxin (Nhe). The persistence of mucin-adherentB. cereusafter simulated gut emptying was determined using a mucin adhesion assay. The stability of Nhe toward bile and pancreatin (intestinal components) in the presence of mucin agar was also investigated.B. cereuscould grow and simultaneously adhere to mucin duringin vitroileal incubation, despite the adverse effect of prior exposure to a low pH or intestinal components. The final concentration ofB. cereusin the simulated lumen at 8 h of incubation was 6.62 ± 0.87 log CFU ml−1. At that point, the percentage of adhesion was approximately 6%. No enterotoxin was detected in the ileum, due to either insufficient bacterial concentrations or Nhe degradation. Nevertheless, mucin appears to retainB. cereusand to supply it to the small intestine after simulated gut emptying. Additionally, mucin may play a role in the protection of enterotoxins from degradation by intestinal components.

Methodology for Enteropathogenic Escherichia coli

1975 ◽  
Vol 58 (2) ◽  
pp. 283-292
Author(s):  
Ira J Mehlman ◽  
Nicholas T Simon ◽  
Arvey C Sanders ◽  
Morris Fishbein ◽  
Joseph C Olson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Elevated Temperature ◽  
Growth Temperature ◽  
Maximal Growth ◽  
Enteropathogenic Escherichia Coli ◽  
Pathogenic Potential ◽  
Gram Negative ◽  
Tentative Identification ◽  
E Coli ◽  
Capsular Antigens

Abstract Pathogenic biotypes of Escherichia coli grow poorly at temperatures greatly different from that of the host. Percentages quantitatively recovered at 42.0, 44.0, 44.5, and 45.5°C in lauryl tryptose broth were 100, 76, 76, and 42, respectively. Corresponding values for 175 strains of varied origin were 98, 89, 82, and 65%. Maximal growth temperature is dependent upon medium. Lauryl tryptose and elevated coliform broths were equivalent in the recovery of small inocula (100 cells/ml) at 41.5–44.5°. Mac-Conkey, enteric enrichment, and Gram-negative broths were inhibitory at corresponding values. Growth at elevated temperature in nutrient broth is enhanced by carbohydrate. Standard lactose enrichment media fail to recover slow lactose fermenters. An acidified glutamic acid medium was unsuitable for recovery of E. coli. The data suggest modification of standard temperatures for the recovery of pathogenic biotypes. Previously recommended analytical methods have been simplified and supplemented. The enhancement of motility in indole-nitrite broth at 35°C is recommended. A 4-tube semiquantitative test is offered for tentative identification of somatic and capsular antigens. Inclusion of Alkalescens-Dispar strains is warranted by their pathogenic behavior. Examination in Shigella and Alkalescens-Dispar sera is required to cover the dysentery-like biotypes. Pathogenic potential cannot be inferred from serotype.

Food Safety: Problems of the Past and Perspectives of the Future1

1982 ◽  
Vol 45 (7) ◽  
pp. 658-660 ◽  
Author(s):  
E. M. FOSTER
Keyword(s):  
United States ◽  
Food Poisoning ◽  
Food Service ◽  
The United States ◽  
Red Tides ◽  
Animal Products ◽  
The Past ◽  
Processing Plants ◽  
Market Areas ◽  
Bacterial Food

Historically, most bacterial food poisoning in the United States is associated with mishandling, either in the home or in the food service establishment. Outbreaks traceable to errors in processing plants are rare. When they do occur they are often associated with changes in processing or packaging technology whose effect is not determined before the product is on the market. Areas of future concern that need research include (1) a better understanding of the mycotoxins; (2) how to minimize Salmonella contamination in animal products; (3) how to prevent, or at least predict, red tides; (4) better bactericidal agents that can be applied to foods; (5) an understanding of the nature and significance of mutagenic agents that are produced in foods during cooking.

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