Concentration of Staphylococcal Enterotoxin from Food Extract Using Copper Chelate Sepharose.

A simple and rapid method is described for detecting as little as 1 ng each of staphylococcal enterotoxins A, B, and C in 100 mL samples of food extracts. Samples were fractionated on copper chelate Sepharose 6B and the recovery of added staphylococcal enterotoxin was measured by the reversed passive latex agglutination test. An approximate 100 fold concentration of toxin was obtained.

Purification of an Escherichia coli serogroup O157:H7 verotoxin and its detection in North American hemorrhagic colitis isolates.

Verotoxin (VT), which is immunologically unrelated to VT1 (Shiga-like toxin I), was purified from the culture filtrate of Escherichia coli hemorrhagic colitis serogroup O157:H7 strain 3657 by copper ion chelate affinity chromatography followed by anion-exchange chromatography. The isoelectric point by sucrose density gradient isoelectric focusing was 5.0, the molecular weight by gel filtration on Superose 12 was about 60,000, and the 50% cytopathic dose for Vero cells was about 1 pg.

Evaluation of radioimmunoassay performance for staphylococcal enterotoxin in foods: application of external quality assessment survey.

An external quality assessment survey for staphylococcal enterotoxin A, B, and C2 determinations was performed in the collaborative study. Three analysts in two laboratories took part. Three types of food, cheese, salami, and pasta, were artificially contaminated with either one toxin only or all three toxins.

Staphylococcus aureus Growth and Thermostable Nuclease and Enterotoxin Production in Canned Salmon and Sardines.

Staphylococcus aureus growth, thermostable nuclease (TNase) and enterotoxin production in inoculated canned salmon incubated at 22 ± 1°C for 4 d were dependent on the size of inoculum, and on the amount of oxygen present in the headspace; under nitrogen with an inoculum of 7 cfu/can, 10-10 cfu/g, no TNase and traces of enterotoxins (A, B, C) were observed; under oxygen with the same inoculum ≥10 cfu/g, ≥6.0 μg TNase and up to 5.2 μg total enterotoxins (A, B, and C)/100 g of salmon were observed.

Breakfast and performance in school children.

The results from two studies are reported of the effects on mental performance of omitting breakfast. The objective of the first study was to compare the performances of schoolchildren who habitually ate or did not eat breakfast. In the second study the effects of omitting breakfast by those accustomed to eating the morning meal were investigated.