摘要:

The effect of aspartame (1‐aspartyl‐1‐phenylalanine, methyl ester) was studied using the protozoan, Tetrahymena pyriformis. Aspartame at levels up to 2500 ppm in a protease peptone —‐ yeast extract medium neither changed the growth rate nor rate of synthesis of DNA, RNA, protein, lipids or glycogen. Cells exposed to as much as 2500 ppm aspartame had a normal morphology. The dipeptide was adsorbed at a level of 0.0353 mg/105cells when (14C) aspartame was added at 2000 ppm to early log cultures and allowed to incubate f

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1978.tb00270.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A total of 112 bacterial strains representing 38 species were tested for their potential to elicit food poisoning outbreaks via histamine formation in foods. Proteus morganii and Enterobacter aerogenes displayed a quantitative superiority in terms of histamine production on a trypticase‐soy broth‐histidine (TSBH) medium and a tuna fish infusion broth (TFIB). When bacteria were incubated under standardized conditions in TSBH medium, histamine accumulated to levels exceeding 50 nmoles/ml of media with a total of 23 strains, including 13 of 15 P. morganii strains, 3 of 3 E. aerogenes strains, 3 of 12 Hafnia alvei strains, 1 of 4 Providencia alcalifaciens strains, 1 of 5 Enterobacter cloacae strains, 1 of 1 Proteus rettgeri strains, and 1 of 1 Citrobacter diversus strains. However, only 8 of the 15 P. morganii strains and the 3 E. aerogenes strains were capable of generating histamine in excess of 200 nmoles/ml in the TSBH medium. Of the 23 strains capable of appreciable histamine production in TSBH medium, P. morganii and E. aerogenes were, by far, the most prolific histamine producers in TFIB. Of the organisms tested, only P. morganii and E. aerogenes would appear to have the capability of forming sufficient histamine in scombroid fish products to elicit food poisoning outbre

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1978.tb00271.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The inhibitory effect of sodium nitrite upon glucose catabolism by Staphylococcus aureus was investigated using [U–1 4C] glucose, liquid chromatography, and gas‐liquid chromatography.Acetate and acetoin are the end‐products of glucose metabolism by S. aureus at 37°C and pH 6.3. In the presence of inhibitory levels of sodium nitrite, acetate and lactate with traces of pyruvate and acetoin are the end products. Acetate production per unit of growth is significantly lower in the sodium nitrite inhibited cultures. The decreased acetoin accumulation was not due to inhibition of diacetyl reduction. The production of acetoin was induced by the addition of acetate to the sodium nitrite containing

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1978.tb00272.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Raw beef rounds were surface inoculated with salmonellae. Some of the rounds were mechanically blade tenderized. Both surface and core samples from each round studied were examined for the presence of and the logarithmic level of salmonellae. Mechanical tenderization increased the level of salmonellae found in core samples by about one logarithm. Large samples taken from cores of rounds which were not tenderized contained small numbers of salmonellae. Dipping inoculated rounds into a 50 ppm chlorine solution did not prevent the occurrence of salmonellae in core samples of mechanically tenderized units. Salmonella survived in the core and on the surface of some but not all inoculated rounds cooked to an internal temperature of 130°F

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1978.tb00273.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Theobromine (0, 2, 4, and 8 mg/ml) had little effect on growth and aflatoxin production by Aspergillus parasiticus NRRL 2999 in a glucose‐mineral salts‐yeast extract medium, indicating that the anti‐aflatoxigenic activity of cocoa beans is not due to the presence of this methylxan

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1978.tb00274.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The attachment of bacteria to chicken and beef meat with and without fascia was studied. It was found that bacteria attach readily to the meat surfaces. The kinetics of attachment depend on the bacterial strain, as well as on the meat surface. Of the bacteria tested, Pseudomonas EBT/2/143 attached most readily to all meat surfaces examined. Chicken breast with fascia was the best surface for attachment.A study was also made of the effects of storage on the multiplication of the attached bacteria and the feasibility of removing them. A high level of Salmonella infantis was found in comparison to the other bacteria after 24 h of storage at 20°C.More investigations are needed to find out whether other serotypes of salmonellae will multiply to similar levels on these surfaces.After micro‐colonies began to form, the newly generated bacteria were easy to remove. The hygienic consequence of this phenomenon is discuss

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1978.tb00275.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Caffeine (1,3,7‐trimethylxanthine) was inactive as a mutagen at the hgprt locus in two human lymphoblast lines at concentrations up to 20 mM. In addition, caffeine did not induce 8‐azaguanine‐resistant mutants in Salmonella typhimurium at similar l

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1978.tb00276.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Book review in this ArticleFood and Beverage Mycology, L. R. Beuchat.Modern Food Microbiology, Second Edition. J. M. Jay.

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1978.tb00277.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY