摘要:

Tuber disks of five potato cultivars, each compatible to the fungus race used, were treated with cell‐free homogenate or lipophilic material obtained from the mycelial mat of Phytophthora infestans. On the effect of treatments, the various cultivars reacted in different manners as regards tissue necrotization and accumulation of phytoalexins rishitin, lubimin and phytuberin. No correlation was found between the extent of tissue necrosis and the level of phytoalexins. Each potato cultivar had a capacity for producing sesquiterpene phytoalexins even if the visible hypersensitive response (tissue necrosis) did not occur. It was concluded that there are compounds of pathogenic origin that induce phytoalexin accumulation as well as necrotization in plant tissues. The expression of necrotization mainly depends on different sensitivity of potato cultivars to treatments. The rate of phytoalexin accumulation would represent a potential for general resistanc

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00261.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Fumigants are used to prevent pest infestations in food and other stored commodities. The quality of the commodity may be affected by fumigant treatment in several ways. Residues of unchanged fumigant may remain in the commodity. Reaction of the individual chemical components of the commodity with the fumigant may alter its chemical or physical properties, thus resulting in changes in flavor, taste, odor, nutritional value or processing qualities. Methyl bromide, ethylene dibromide, ethylene dichloride, carbon tetrachloride, phosphine and ethylene oxide are the major fumigants used for treatment of grains, vegetables and fruits. Their effects on food quality and the significance of residues in treated commodities are reviewed.

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00262.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

A chemically defined synthetic medium was developed on which Phytophthora infestans (Mont.) de Bary strain 1.2.4 grew extensively. The medium consisted of: 90.0 g maltose; 20.0 g L‐proline; 20.0 g DL‐alanine; 1.0 g KNO3; 0.50 g KH2PO4; 0.25 g MgSO47H2O; and 1.0 mg thiamin per liter of distilled water. The average level of growth on this medium was 0.5864 g dry weight mycelium per 50 ml medium. The glycoalkaloids, solanidine and solanine, were produced by P. infestans in this medium at an average concentration of 0.8518 mg total glycoalkaloids per 25 ml medium with a range of 0.0 to 5.9 mg per 25 ml. No glycoalkaloid production was detected when the level of growth of the fungus was below 0.35 g dry weight mycelium/50 ml medium. Glycoalkaloids were synthesized by 5 of 10 cultures grown on chick pea medium and by none of 10 cultures grown on rye seed med

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00263.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Enterotoxin A and thermonuclease were produced by Staphylococcus aureus cell populations in all growth phases. Synthesis of entero‐toxin was more rapid than that of thermonuclease early in the exponential phase, whereas later in the exponential phase the thermonuclease synthesis was more rapid than that of enterotoxin. The optimum temperature for enterotoxin production was 42°C, while that for thermonuclease production was in the range 27–33°C. Small amounts of enterotoxin and thermonuclease were released at temperatures up to 45°C.During heat treatment of staphylococcal cells, enterotoxin production was not observed at temperatures in excess of those permitting growth, although small amounts of thermonuclease were produced. Intracellular enterotoxin was not detected after disintegration of cells under pressure at –30°C. Enterotoxin at detectable concentration, was not bound to the cell membranes. All the results obtained indicate that the synthesis of enterotoxin by S. aureus is intimately associated with ce

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00264.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The analysis of several breakfast cereals has shown that methyl chloroform (MCF, 1,1,1‐Trichloroethane), a solvent found to be present in the adhesive of the outer box, can migrate from the adhesive through the box and the waxed liner into the cereal. The levels of MCF in the adhesive, the outer box, the waxed liner and the cereal were found to range from 0 to 2.3%, 0 to 19.4 ppm, 0 to 4.8 ppm, and 0 to 0.40 ppm, respectively, in 11 breakfast cereals. The MCF residues were determined using a closed system‐vacuum distillation gas chromatographic technique with both electron capture and electrolytic conductivity detection. The results were confirmed by high resolution mass spectrome

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00265.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Swine were fed a diet containing hexachlorobenzene (HCB) in order to generate contaminated pork which was subsequently cooked and fed to female cats. Feeding the fresh weight equivalent of 50 g cooked pork/day/cat (1

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00266.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The kinetics of distribution of ochratoxin A (OA) in chicken tissues was studied. Day‐old chicks were fed a starter diet alone or containing 1 ppm OA. After 5 weeks, all chicks were intubated with 50 μg3H‐OA per chick. The highest level of radioactivity was found in kidney and liver 8 hr after intubation. Peak levels of OA in kidney, liver and breast were found to be 12, 4, and 0.2 ppb, respectively. Over 90% of the radioactivity was eliminated 48 hr after intubation. Moreover, when laying hens were fed a diet containing 0.5 or 5.0 ppm of OA for 2 weeks, the highest levels of OA were found in the kidney (124 ppb) and liver (80 ppb) also. Levels of OA in breast, leg and eggs of laying hens were found to be 8, 7, and 2.8 ppb, respecti

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00267.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Book review in this ArticleFood Microbiology: Public Health and Spoilage Aspects, M. P. deFigueiredo and D. F. Splittstoesser.

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00268.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00269.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY