THE SANITARY SIGNIFICANCE OF THE FECAL AND ORAL STREPTOCOCCI IN WATER ANDFOODS

THE SANITARY SIGNIFICANCE OF THE FECAL AND ORAL STREPTOCOCCI IN WATER AND FOODS BY STEVEN WEINSTEIN A study was undertaken to evaluate the use of the fecal and oral streptococci as indicator organisms of contamination of water and foods. Two major objectives were pursued. The first was to determine to what extent the fecal streptococci occur apart from the intestinal tracts of humans and animals, and to determine whether the presence of these organisms in soil and plants could be ascribed to sources other than those arising through human or animal contamination. The results showed that the numbers of fecal streptococci in unfertilized and commercially fertilized soil fluctuated with the season. Greater numbers occurred in the summer months than in winter. The number of fecal streptococci correlated more closely with the numbers of the fecal coliforms than with the coliforms. It was noted in this study that apparently 30-40 per cent of the streptococci isolated from soil and plants could not be placed in any of the established species because of their divergency in the fermentation of certain sugars. These organisms fulfilled all the requisites for Sherman's enterococcus group and were designated S_. faecalis-like and S. faecium-like. The S. faecium-like organisms occurred most frequently. In this study yellow pigmented streptococci were isolated from garden soil in the early spring and late summer. Fecal streptococcus-like organisms were isolated from the exterior surfaces of corn, tomatoes, and green beans but rarely on the interiors parts of the vegetables. It was concluded from the distribution and types of fecal streptococci present in soil and on plants that their presence was most likely due to animal or insect contamina­ tion. The second objective was to evaluate the use of Streptococcus salivarius and streptococcus aitis as indicators of human pollution of water and foods. A new and improved medium for their isolation was developed. The medium is a mannitol-azide broth with the incorporation of penicillin and kanamycin. It was called penicillinkanamycin MS broth. It was used to enumerate S. salivarius and £. mitis in human feces and foods while inhibiting the growth of all other organisms. The average number of oral streptococci in human feces was ten thousand per gram. However, when discharged into sewage or water, these organisms died out much too rapidly to be detected 24 hours later. Thus the failure to isolate S. salivarius and JJ. mitis in sewage led to the conclusion that these organisms would not be useful indicators of human fecal pollution of water. The penicillin-kanamycin MS broth was used to test for the presence of the oral streptococci in frozen meat pies. S. salivarius and £». mitis were isolated from 71 per cent of the samples examined ranging in numbers from 7 to 17,500 per gram. It was also noted that when large numbers (over 1000 per gram) of fecal streptococci were encountered there was a corresponding increase in the number of oral streptococci present. This suggested that the source of these organisms was due to both fecal and oral contamination. An experiment was designed in an effort to trace one possible route by which S. salivarius and S. mitis may enter a food product. It was established that if these organisms come into contact with a surface such as a stainless steel counter they will remain viable for periods up to 72 hours. From this study it was concluded that these organisms have an excellent chance of being introduced into a food product by surface contaminated hands or materials. The presence of these organisms in foods would represent oral pollution by coughing and sneezing in addition to fecal pollution. Since neither j». salivarius nor £. mitis have been isolated from animals, the presence of these organisms in foods would represent pollution by the human rather than by both human and animal as is the case with Escherichia coli and with the fecal streptococci. Thus a sensitive testing methodology has been achieved which permits a more critical evaluation of handling procedures.