摘要:

ABSTRACTThirty seven strains of lactobacilli and leuconostocs were screened for bacteriocin production. A bacteriocin‐like substance (designated lacidin A) was detected in culture filtrate of Lactobacillus acidophilus OSU133. Lacidin A inhibited Enterococcus faecalis, L. acidophilus, Lactobacillus delbrueckii subsp. lactis, and Staphylococcus aureus. The bacteriocinogenic nature of lacidin A was confirmed by eliminating the inhibitory effects of acid, hydrogen peroxide and phage and by loss of activity upon hydrolysis with proteolytic enzymes. The bacteriocin is relatively heat‐stable and has considerable bactericidal action against S. aureus in phosphate buffer. Lacidin A also demonstrated bacteriostatic action against S. aureus in brain heart infusion and heat‐treated milk and liquid whol

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1994.tb00587.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTGrowth and survival patterns ofListeria monocytogenesstrain Scott A were studied in brain heart infusion broth containing sodium diacetate. Minimum inhibitory concentrations decreased with decrease in temperature, from 35 and 32 mM at 35C and 20C, respectively, to 28 mM at 5C. Broth pH containing 35, 32, and 28 mM sodium diacetate was 5.25, 5.40 and 5.60, respectively. Sodium diacetate was more effective than acetic acid alone in inhibiting the organism over the pH range of 5.0‐6.0. Addition of 21 mM (0.3%) sodium diacetate to ground beef or beef slurry suppressed total aerobic counts during refrigerated storage. Although the meat pH decreased from 5.6 to 5.2 by the addition of the compound, a major part of the antimicrobial effect was attributed to the diacetate and not just pH. Sodium diacetate suppressed growth of three additional L. monocytogenes strains and strains of Escherichia coli, Pseudomonas fluorescens, Salmonella enteriditis and Shewanella putrefaciens. P. fragi, Yersinia enterocolitica, Enterococcus faecalis, Lactobacillus fermentis and Staphylococcus aureus were insensitive to the compound. Sodium diacetate has potential for use in controlling growth of listeriae in meat, poultry and fish products and suppressing growth of certain Gram‐negative spoilage and pathogenic microorgani

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1994.tb00588.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThirty eight samples of fresh, frozen and dry seafoods and 27 samples of fresh and cold stored meat and meat products obtained from retail shops were examined for the presence ofListeriaspp. Direct plating of the sample homogenate on Listeria Selective Agar (LSA) was compared with the two step enrichment method devised by Hao et al. for detecting Listeria spp. in vegetables. We report that modification of this methodology involving cold enrichment for 48 h in Brain Heart Infusion (BHI) at 10C followed by enrichment at 37C inListeriaenrichment broth (LE) resulted the enumeration of a large population ofListeriafrom flesh foods.Listeriaisolates from fish and meat were identified by employing the cultural methods given in modified version of the Bacteriological Analytical Manual (Lovett and Hitchins 1988).Listeriaspp. from seafoods were identified, with the order of predominance as L. grayi, L. innocua, L. murrayi, L. seeligeri. Samples of meat and their products were found to be contaminated mainly with L. innocua and L. murrayi. In contrast, screening of an independent batch of 20 fish and meat samples by adopting the PHLS (UK) method revealed predominance of L. grayi and L. seeligeri in fish and presence of additional species like L. seeligeri, L. ivanovii and L. welshimeri in meat products. None of the methods however could detect incidence of L. monocytogenes in any of the samples tested from local market in Bombay.

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1994.tb00589.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe antibacterial activity of monolaurin and triglycerol 1,2 laurate alone and combined with three different chelating agents, at different pH (7, 6, 5.5 and 5), different NaCl concentrations (0.5 to 7%) and various combinations of pH and NaCl concentrations was investigated. The activity of these agents against 16 bacteria (7 Gram‐positive and 9 Gram‐negative) was studied using the spiral gradient end point test to determine the minimum inhibitory concentration (MIC).Monolaurin was effective against all the Gram‐positive bacteria studied, but was only effective against the Gram‐negative bacteria in the presence of EDTA. The inhibition was greatest at low pH and high NaCl concentrations. Concern has been expressed about the use of monolaurin in foods because of its poor solubility. Polyglycerol esters are more soluble and antimicrobial activity of these compounds has been observed. Triglycerol 1,2 laurate exerted some inhibitory effects, but was not as inhibitory as monolaurin even in the presence of the chelating agent and under conditions of low pH and high NaCl levels. Other chelators investigated (monoglyceride citrate and sodium citrate) did not promote the inhibitory effect of mon

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1994.tb00590.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe adherence and viability ofEscherichia coliinoculated onto the surfaces of plastic cutting boards and new and used wood cutting boards were evaluated. Most of the inoculum was recovered from all surfaces after resident drying times of 5 min and from plastic surfaces at 24 h. When the exposure time was extended to 2 h,>90% of the cells placed on new and used dry wood surfaces were not recovered after vigorous rinsing. Scanning electron microscopy showed that the bacteria resided within the structural xylem fibers and vegetative elements of the wood. After resident drying times of up to 2 h, almost 75% of the adherent bacteria on the wood surfaces were viable, as defined by a nalidixic acid direct viable count procedure. Microcosm studies showed no intrinsic growth‐supporting or toxic properties of the cutting board materials. Bacteria that adhered to plastic surfaces were more easily removed by low‐temperature washing than were cells that adhered to wood surfaces. These studies demonstrated that bacteria adhering to wood surfaces resided within the structural and vegetative elements of the wood's xylem tissues and were viable; wood was more retentive than plastic; penetration of the inoculum liquid promoted cell adherence to the wood matrix; and conditioning of wood with water before inoculation interfered with bacterial adhere

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1994.tb00591.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1994.tb00592.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Book reviewed in this article:THE LACTIC ACID BACTERIA. E.L. Foo, H.G. Griffin, R. Mollby and C.G. Heden (Editors)

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1994.tb00593.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY