摘要:

Previous epidemiological studies of nasopharyngeal carcinoma suggest that traditional food items, particularly salted fish, consumed by southern Chinese may play a role in the cause of the high frequency of the disease among them. We report here the results of an analysis by combined gas chromatography and high resolution mass spectrometry of six types of salted fish and ten other items of traditional southern Chinese salted food products for the presence of volatile nitrosamines. Only N‐nitroso‐dimethylamine (NDMA) was detected in some of the samples of salted fish examined. No volatile nitrosamine other than those added as internal standards was detected in any of the oth

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00254.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Growth, sporulation and enterotoxin formation in various foods inoculated with a Clostridium perfringens type A enterotoxin‐producing strain were studied. Good vegetative growth, 107–108cells/g, was obtained after 4 hr of anaerobic growth and remained almost the same throughout the 20–24 hr observation in most of the foods. A gradual increase in spore count to the level of 104–105/g was observed with an increase in the incubation time. Enterotoxin was detected in moist cooked chuck roast, ground beef and turkey as well as in moist cooked and dry roasted chicken at levels up to 0.125μg/g. The earliest time at which enterotoxin was detected was after 10 hr of anaerobic growth in moist cooked turkey at 37°C. Although growth and some sporulation occurred, enterotoxin was not detected in dry roasted beef or turkey with or without gravy, or in moist cooked pork or lamb. Poor growth and sporulation also were obtained with chicken broth, chicken gravy and beef gravy. In moist cooked turkey that had been temperature abused for 6 hr at 37°C, held cold for 15 hr and reheated to 37°C, toxin could be detected after only 5 hr of holding at 37°C. The ability of certain foods to support sporulation and enterotoxin formation indicates that such preformed enterotoxin may contribute to early onset of symptoms in some cases of C. perfringens fo

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00255.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The effects of pyruvate, succinate, citrate, alpha‐keto glutarate, fumarate, malate, lactate, and glycerol supplementation (0.5, 1.0, and 2.0 g/100 ml) on aflatoxin production by A. parasiticus NRRL 2999 were examined in synthetic and semi‐synthetic media. Glycerol, lactate, and the 0.5 g/100 ml level of pyruvate stimulated production in the synthetic medium. At the 2.0 g/100 ml level, pyruvate, citrate, alpha‐keto glutarate, fumarate, and malate inhibited aflatoxin accumulation in both media. With the exception of glycerol, all supplements stimulated sporulation and elevated the pH of the cul

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00256.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Top and bottom round steaks inoculated with Yersinia enterocolitica were stored vacuum packaged and in polyvinyl chloride (PVC) films at 1, 2.5 and 5°C for 21–35 days. Y. enterocolitica and total aerobic plate counts of steaks were consistently higher in the more oxygen permeable film (PVC) than in the vacuum packages. The microbial flora of the vacuum packaged steaks at the end of the storage period (21–35 days) consisted, in addition to Y. enterocolitica, primarily of Lactobacillus spp., that of the steaks stored in PVC of Pseudomonas

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00257.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were applied to six strains of toxigenic and six strains of non‐toxigenic Aspergillus flavus in a method similar to antibiotic susceptibility testing. The cultures were examined for growth inhibition, spore formation, pigmentation, and aflatoxin production. BHA (0.005–0.020 g per plate) had an inhibitory effect on growth and toxigenesis of the test organisms, while BHT (0.005–0.020 g per plate) had no visible inhibitory effects. Sporulation of the cultures had no direct relationship with toxigenesis in the presence of BHA. However, pigmentation of the mycelium is directly related to the intensity of fluorescence of the culture under UV. Heating of BHA did not reduce the inhibitory effect of the compound on A. f

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00258.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The molecular sizes of Clostridium botulinum type A, B, E, and F toxins produced in string beans, mushrooms, tuna fish and pork were determined to provide an explanation for the high botulogenic properties of vegetables. Type A and B organisms produced the orally more toxic 16S and 19S molecular‐sized toxins in vegetables, whereas they produced the orally less toxic 12S and only rarely some 16S toxin in tuna fish and pork. Type E and F organisms produced only 12S toxin in any food or culture medium, but addition of glucose seemed essential for appreciable toxin production. It appeared that the molecular sizes of type A and B toxins transform depending upon the content of iron and manganese salts in food

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00259.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

A solid‐phase radioimmunoassay (RIA) for aflatoxin B1(afla B1) was developed. This method involved the incubation of afla B1, both labelled and unlabelled, with immunoglobulin (IgG)‐sepharose gel which was prepared by conjugation of the IgG highly specific to afla B1with CNBr‐activated sepharose gel, followed by a filtration step. The binding capacity was determined by counting the radioactivity in the filtrate. Studies with different afla B1analogues revealed that the IgG‐gel bound most effectively with B1. Binding of afla B2, G1, G2, and aflatoxicol to the IgG‐gel was less effective in comparison with the IgG before coupling. Between 0.5–5.0 ng per assay, the displacement of radioactivity from the gel was directly proportional to the amount of afla B1present. Using a simple extraction procedure without clean‐up step, the recovery yields for afla B1in the contaminated corn or wheat at levels of 5 ppb or above w

ISSN:0149-6085    

DOI:10.1111/j.1745-4565.1977.tb00260.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY