COMPARISON OF ESCHERICHIA COLI AND STREPTOCOCCUS FAECALIS AS A TEST ORGANISM TO DETERMINE THE SANITARY QUALITY OF FOOD

1954 ◽  
Vol 17 (8) ◽  
pp. 237-242
Author(s):  
C. H. Allen ◽  
F. W. Fabian

Part II Six strains of E. coli and two strains of Strept. faecalis were seeded into 12 different foods having a pH range of 2.8 to 6.7. Viability tests were run at different time intervals to study the viability of these organisms in the different foods under normal conditions. The results showed that the growth curve of E. coli in the foods depended upon the food and that the height of the curve was determined by the initial inoculation. E. coli var. communis was more viable in the foods than were the other strains. Strept. faecalis remained viable longer in some of the acid foods such as orange juice with a pH of 3.5 and mayonnaise with a pH of 3.7 than did any of the strains of E. coli. There appeared to be little difference between the viability of the two organisms in the less acid foods within the time limits studied.

1986 ◽  
Vol 49 (1) ◽  
pp. 33-36 ◽  
Author(s):  
ROBERT H. MADDEN ◽  
H. BULLER ◽  
D. W. McDOWELL

A comparison of the recoveries of Clostridium perfringens, Escherichia coli and Streptococcus faecalis from naturally and artificially contaminated mussels and oysters was made. Only C. perfringens was regularly recovered from naturally contaminated shellfish. Laboratory studies showed that this was due to C. perfringens spores retaining viability significantly longer than vegetative cells of the other organisms tested, under marine conditions. Over 97% of presumptive C. perfringens colonies were confirmed as positive. A survey of mussels at 24 sites, over ca. 60 km of coastline, found C. perfringens at 23 but E. coli at only two of the sites. Therefore, enumeration of C. perfringens can indicate fecal pollution where enumeration of E. coli shows none. Also, confirmation of presumptive colonies may not be required, rendering enumeration more rapid. Despite the greater persistence of C. perfringens spores, studies in a commercial depuration tank showed that oysters were cleansed to an acceptable level using a standard 48-h immersion. Depuration was found to be essential because all three organisms tested survived for a considerable period of time in oysters stored dry at 4°C, which is normal commercial practice.


1954 ◽  
Vol 17 (7) ◽  
pp. 204-218 ◽  
Author(s):  
C. H. Allen ◽  
F. W. Fabian

Since the discovery of the role that bacteria play in disease, a search has been made for a suitable organism that would be indicative of dangerous bacterial contamination in food. Early work with pathogenic bacteria indicated that they would not be suitoble to serve this purpose since they were hard to isolate, were too fastidious, and died off quickly under conditions favorable for keeping food. For these and other reasons the search turned to other bacteria associated with pathogenic bacteria but which were hardier and easier to work with and identify. Fullfilling these requirements were two organisms, E. coli and Strept. faecalis, normal inhabitants of the intestinal tract and associated with many pathogenic bacteria especiallv the enteric bacteria which ore responsible for many food outbreaks. Today the presence of moderate numbers of these organisms is not considered a sure sign of dangerous contamination but rather of possible contamination. Their presence indicates that a search for the cause of the contamination should be made.


1999 ◽  
Vol 62 (3) ◽  
pp. 277-279 ◽  
Author(s):  
M. LINTON ◽  
J. M. J. McCLEMENTS ◽  
M. F. PATTERSON

The effect of high pressure on the survival of a pressure-resistant strain of Escherichia coli O157:H7 (NCTC 12079) in orange juice was investigated over the pH range 3.4 to 5.0. The pH of commercial, sterile orange juice was adjusted to 3.4, 3.6, 3.9, 4.5, or 5.0. The juice was then inoculated with 108 CFU ml−1 of E. coli O157:H7. The inoculated orange juice was subjected to pressure treatments of 400, 500, or 550 MPa at 20°C or 30°C to determine the conditions that would give a 6-log10 inactivation of E. coli O157:H7. A pressure treatment of 550 MPa for 5 min at 20°C produced this level of kill at pH 3.4, 3.6, 3.9, and 4.5 but not at pH 5.0. Combining pressure treatment with mild heat (30°C) did result in a 6-log10 inactivation at pH 5.0. Thus, the processing conditions (temperature and time) must be considered when pressure-treating orange juice to ensure microbiological safety.


2017 ◽  
Vol 18 (0) ◽  
Author(s):  
Camila Sampaio Cutrim ◽  
Raphael Ferreira de Barros ◽  
Robson Maia Franco ◽  
Marco Antonio Sloboda Cortez

Abstract The purpose of this study was to evaluate the behavior of E. coli O157:H7 during lactose hydrolysis and fermentation of traditional and low lactose yogurt. It also aimed to verify E. coli O157:H7 survival after 12 h of storage at 4 ºC ±1 ºC. Two different types of yogurts were prepared, two with whole milk and two with pre-hydrolyzed whole milk; in both groups one yogurt was inoculated with E. coli O157:H7 and the other one was not inoculated. The survival of E. coli and pH of yogurt were determined during fermentation and after 12-h refrigeration. The results showed that E. coli O157:H7 was able to grow during the fermentation period (from 4.34 log CFU.mL-1 to 6.13 log CFU.mL-1 in traditional yogurt and 4.34 log CFU.mL-1 to 6.16 log CFU.mL-1 in low lactose yogurt). The samples with E. coli O157:H7 showed gas formation and syneresis. Thus, E. coli O157:H7 was able to survive and grow during fermentation of traditional and low lactose yogurts affecting the manufacture technology. Moreover, milk contamination by E. coli before LAB addition reduces the growth of L. bulgaricus and S. thermophilus especially when associated with reduction of lactose content.


1975 ◽  
Vol 74 (3) ◽  
pp. 431-440 ◽  
Author(s):  
P. A. Ayres

SUMMARYIncidents of non-specific illness associated with the consumption of oysters have highlighted the lack of published information on the bacteriology of shellfish suitable for consumption. Investigations showed that the majority of molluscan shellfish entering English markets conform to the accepted standard of less than 5 Escherichia coli/ml. tissue. The numbers of E. coli were related to the sanitary quality of the growing area but no relation could be established between numbers of E. coli and coliforms, faecal streptococci or Clostridium welchii. The numbers of non-specific bacteria varied considerably but shellfish from sources associated with non-specific illness yielded relatively high counts at 37° C. The results showed that there was no justification for a standard based on total plate counts, which often exceeded 106/g. Such a standard would have to be coupled with spoilage or the incidence of non-specific illness. The relation between the numbers of non-specific bacteria growing at 20 and 37° C. appears to be a useful measure for assessing the likelihood that raw shellfish are a public health risk.


2012 ◽  
Vol 10 (3) ◽  
pp. 243 ◽  
Author(s):  
Hanna Lethycia Wolupeck ◽  
Helen Caroline Raksa ◽  
Luciane Silvia Rossa ◽  
Raquel Biasi ◽  
Renata Ernlund Freitas de Macedo

O queijo Minas frescal é um dos mais populares do Brasil, porém o alto teor de umidade associado ao métodode processamento, muitas vezes artesanal, e de armazenamento desse produto o tornam muito perecível.Este trabalho teve como objetivo avaliar e comparar a qualidade microbiológica de queijo Minas frescalcomercializado na cidade de Curitiba (PR) nos anos de 1999 e 2009, verificando a evolução na qualidadehigiênico-sanitária desse produto no período de 10 anos. Foram analisadas 11 marcas comerciais de queijo Minas frescal disponíveis no comércio varejista da cidade de Curitiba, sendo amostradas cinco unidades de cada marca, totalizando 55 amostras. Os queijos foram submetidos à pesquisa de Salmonella spp., contagem de coliformes totais e Escherichia coli, contagem de Staphylococcus coagulase positiva e contagem de aeróbios mesófilos, com resultados expressos em UFC/g. Das 55 amostras de queijo, 41,82% e 78,18% apresentaram contagem de E. coli e de coliformes totais acima do limite permitido, respectivamente. Somente uma amostra (1,82%) do total avaliado mostrou-se em desacordo com os padrões para S. coagulase positiva e uma para Salmonella spp. Ambas as amostras foram adquiridas em 2009. Todas as amostras avaliadas em 2009 apresentaram elevada contagem de aeróbios mesófilos, revelando alta carga microbiana. Comparativamente, os queijos avaliados em 1999 mostraram qualidade microbiológica superior aos queijos avaliados em 2009 (p < 0,05). Destes, 100% apresentaram no mínimo um parâmetro microbiológico em desacordo com a legislação vigente, indicando que a qualidade dos queijos Minas frescal avaliados em 2009 apresentou-se inferior a dos queijos avaliados em 1999.


2021 ◽  
Vol 25 (4) ◽  
pp. 13-22
Author(s):  
Mohammed A. Rashid ◽  
◽  
Nagam O. Kariem ◽  

This study was intended to evaluate the quality of some bottled waters available in Iraqi market, by testing their physical, chemical and biological characteristics. These samples produced by four companies during the period of December- 2016 to April-2017. The selected companies had the biggest sells and were under the trade names of AlluLua, Ala, Alwafi, and Venesia. The results showed that most bottled waters samples characteristics were in compliance with Iraqi and international standards, with some superiority in water quality for the trade mark Allulua upon the other companies, but the trade mark Ala was at the end of the list of quality rank. All the tested samples showed clean bacteriological results for coliforms as pollution indicators and fecal coliforms (all tests MPN was less than 1.1). The other physical and chemical characteristics showed pH range of 6.21 ~ 7.7, TDS of 12.81 ~ 126.88 mg/L, Ca of 0.24 ~ 25.5 mg/L, Mg of 3.2 ~ 13.1 mg/L, Na of 0.92 ~ 23 mg/L, K of 0 ~ 0.39 mg/L, Hardness of 3.8 ~ 38.2 mg/L, and chloride of 3.55 ~ 35.5 mg/L.


2001 ◽  
Vol 64 (6) ◽  
pp. 783-787 ◽  
Author(s):  
CAROLYN M. MAYERHAUSER

Escherichia coli O157:H7 survival in acid foods such as unpasteurized apple cider and fermented sausage is well documented. Researchers have determined that E. coli O157:H7 can survive in refrigerated acid foods for weeks. The potential of acid foods to serve as a vector of E. coli O157:H7 foodborne illness prompted this study to determine the fate of this organism in retail mustard containing acetic acid when stored at room and refrigerated temperatures. Various retail brands of dijon, yellow, and deli style mustard, pH ranging from 3.17 to 3.63, were inoculated individually with three test strains of E. coli O157:H7. Samples were inoculated with approximately 1.0 × 106 CFU/g, incubated at room (25 ± 2.5°C) and refrigerated (5 ± 3°C) temperatures, and assayed for surviving test strains at predetermined time intervals. An aliquot was appropriately diluted and plated using sorbitol MacConkey agar (SMAC). When the test strain was not recoverable by direct plating, the sample was assayed by enrichment in modified tryptic soy broth and recovered using SMAC. Growth of E. coli O157:H7 test strains was inhibited in all retail mustard styles. E. coli O157:H7 was not detected in dijon style mustard beyond 3 h at room and 2 days at refrigerated temperatures. Survival in yellow and deli style mustard was not detected beyond 1 h. Overall, test strain survival was greater at refrigerated than room temperature. Retail mustard demonstrated the ability to eliminate effectively any chance contamination by this organism within hours to days, suggesting that these products are not a likely factor in E. coli O157:H7 foodborne illness.


1977 ◽  
Vol 40 (11) ◽  
pp. 790-794 ◽  
Author(s):  
JAMES F. FOSTER ◽  
JAMES L. FOWLER ◽  
WARREN C. LADIGES

The microbiological quality of 150 units of raw ground beef obtained from a local retail store was determined. The range of aerobic plate counts was from 6.9 × 104 to 8.3 × 107/g. By using the most probable number method 96.7% of the 150 units were positive for coliforms, 94.7% for Escherichia coli and 61.3% for Staphylococcus aureus. By the plate methods, 99.3% of the units were positive for fecal streptococci and 56% were positive for Clostridium perfringens. No salmonellae were isolated. Aerobic and anaerobic organisms were isolated and identified. E. coli was the most frequently isolated aerobe followed by organisms in the Klebsiella-Enterobacter group. Among the anaerobic isolates, C. perfringens was the organism most frequently encountered.


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