RESUMO
An investigation is presented on industrial contamination by benzotrifluoride percolation into ground water used for drinking water, in a populated area of 20 km(2) at Trissino, north Italy, due to improper chemical waste disposal. Hydrogeological features of the situation are reported, as well as the emergency action taken, such as the surveys made and their analytical results. The epidemiology of the emergency is examined and rehabilitation measures are presented and discussed. Fortunately no major ecological or social disaster occurred, In part thanks to the speed and efficiency with which the affair was handled. It is notable that the authorities kept the public duly informed and thus retained their confidence.
RESUMO
The effect of starter culture and chemical acidulation on the growth and enterotoxigenesis of Staphylococcus aureus strain S-6 in Italian dry salami under commercial manufacturing conditions was studied. The experimental design included two levels of S. aureus (10 and 10/g), three levels of starter culture (0, 10, and 10/g), three levels of initial pH (pH(0)) (6.1, 5.5, and 4.8), two manufacturing plants, and three replications. S. aureus growth in the salami was affected significantly (P < 0.005) by pH(0), initial levels of S. aureus (staph(0)) and lactic acid bacteria (LAB(0)), day of fermentation, and by the interactions of pH(0) x day, pH(0) x LAB(0), LAB(0) x staph(0), pH(0) x staph(0), and pH(0) x location of fermentation. In general, the lower the pH(0) and the higher the LAB(0), the greater the inhibition of S. aureus. The LAB levels during the fermentation were affected significantly (P < 0.005) by pH(0), LAB(0), day of fermentation, location, LAB(0) x pH(0), and LAB(0) x day. Derived regression equations related level of S. aureus and LAB at any day of fermentation to a number of microbiological and chemical variables. Close similarity of observed and predicted levels of S. aureus and LAB growth demonstrated the usefulness of the experimental approach in evaluating the safety of a process. No detectable enterotoxin or thermonuclease was found at any stage of processing even when S. aureus reached levels of 10/g of salami.
RESUMO
Three strains of Staphylococcus aureus (S-6, 137 and 472) were inoculated, in duplicate, into Italian-style dry salami made with finished product as starter and processed under commercial manufacturing conditions. Five levels of S. aureus ranging from 2.2 × 102 - 1.8 × 107 cells/g were used. A fourth strain (264) was inoculated at a level of 105 cells/g. All strains of S. aureus grew at every level of inoculation, but the amount of growth was dependent on inoculum size. Strains S-6 and 472 increased in number by 1.2 - 2.9 logs (mean 2.14) at inoculum levels of 2.3 × 102 - 2.5 × 103 cells/g, and by 2.1 - 3.2 logs (mean 2.66) at inoculum levels of 3.7 × 104 - 6.6 × 105 cells/g. Strain 137 was very sensitive to salami environment and only increased by 0.47 - 1.86 logs (mean 1.23) even at the greatest inoculum level. Strain 264 increased in numbers by 1.5 logs in the presence of 5 × 105 inoculated lactobacilli/g and by 2.5 logs in the presence of 6 × 104 naturally occurring lactic acid bacteria. Staphylococci occurring naturally in salami mix were unable to grow to levels greater than 2 × 104 cells at any time during processing of experimental sausages. Thermonuclease was detected only in salamis inoculated with strains S-6 and 472 at initial levels of greater than 3.7 × 104 cells/g and only when growth reached levels greater than 107 cells/g. No enterotoxin was detected in any of the inoculated samples. Development of regression equations allowed description of the growth of inoculated S. aureus in the salami during manufacturing as affected by a number of variables.
