Evaluation of cytotoxicity and genotoxicity of Acacia aroma leaf extracts.

Acacia aroma, native plant from San Luis, Argentina, is commonly used as antiseptic and for healing of wounds. The present study was conducted to investigate the in vitro cytotoxicity and genotoxicity of hot aqueous extract (HAE) and ethanolic extract (EE) of A. aroma. The cytotoxic activity was assayed by neutral red uptake assay on Vero cell. Cell treatment with a range from 100 to 5000 µg/mL of HAE and EE showed that 500 µg/mL and 100 µg/mL were the maximum noncytotoxic concentrations, respectively. The CC50 was 658 µg/mL for EE and 1020 µg/mL for HAE. The genotoxicity was tested by the single-cell gel electrophoresis comet assay. The results obtained in the evaluation of DNA cellular damage exposed to varied concentrations of the HAE showed no significant genotoxic effect at range of 1-20 mg/mL. The EE at 20 mg/mL showed moderate genotoxic effect related to the increase of the DNA percentage contained in tail of the comet; DNA was classified in category 2. At concentrations below 5 mg/mL, the results of cytotoxicity and genotoxicity of aqueous and ethanolic extracts of Acacia aroma guarantee the safety at cell and genomic level. However further studies are needed for longer periods including animal models to confirm the findings.

Antibacterial activity of extracts of Acacia aroma against methicillin-resistant and methicillin-sensitive Staphylococcus

Antibacterial activity of organic and aqueous extracts of Acacia aroma was evaluated against methicillin-resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus epidermidis. Inhibition of bacterial growth was determined using agar diffusion and bioautographic methods. Among all assayed organic extracts only ethanolic and ethyl acetate extracts presented highest activities against all tested Staphylococcus strains with minimal inhibitory concentration (MIC) values ranging from 2.5 to 10 mg/ml and from 2.5 to 5 mg/ml respectively. The aqueous extracts show little antibacterial activity against Staphylococcus strains. The bioautography assay demonstrated well-defined growth inhibition zones against S. aureus in correspondence with flavonoids and saponins. A. aroma would be an interesting topic for further study and possibly for an alternative treatment for skin infections.

Antibacterial activity of flavonoids against methicillin-resistant Staphylococcus aureus strains.

An experimental and theoretical study was performed on the anti-staphylococcal activity of 18 natural and synthetic flavonoids against methicillin-resistant Staphylococcus aureus strains. The analysed flavonoids belong to three well-differentiated structural patterns: chalcones, flavanones and flavones. The quantitative analysis of the anti-staphylococcal activity of the compounds was carried out by determining their percent inhibition degree. The hierarchical cluster analysis method was used to analyse the anti-MRSA activity of the compounds. With this methodology, the flavonoids were classified into four groups according to their anti-staphylococcal activity (high, sufficient, intermediate and low). The carbonylic region is of importance because it is part of the bioactive region inducing anti-MRSA activity in the flavonoid molecules. The introduction of OH groups in positions 2' of chalcones and 5 of flavanones (or flavones) increases flavonoid activity, while the OCH(3)groups produce the reverse effect. Using the experimental anti-MRSA activity data of flavonoids and six quantum chemical parameters calculated by means of the AM1 semiempirical molecular orbital method, a very good quantitative structure-activity relationship was obtained (confidence range: 95%; significance level for tests: 0.05; correlation coefficient=0.9842). The selected parameters explain 96.86% of the percent inhibition degree. The obtained relation is consistent with the conclusions formulated in this paper and serves as a theoretical support for some of them. Finally, it is concluded that the flavonoids chalcone, 2'(OH)-chalcone, 2',4'(OH)(2)-chalcone and 2',4(OH)(2)-chalcone might constitute promising therapeutic agents against infections with methicillin-resistant S. aureus strains.

Detección de esporas de Clostridium botulinum en mieles / Detection of Clostridium botulinum in honey

Se examinaron 177 muestras de miel para la detección de Clostridium botulinum; 68 procedentes del comercio, 95 de apiarios envasados en origen, 8 de apiarios rurales para consumo familiar y 6 de establecimientos fraccionadores en las provincias de San Luis y Mendoza. Utilizando el método de dilución-centrifugación, se detectó C. botulinum tipo A en 2 muestras de apiarios rurales de San Luis (1,1 o/o); en una de ellas se logró la recuperación de la cepa y el recuento de esporas fue de 55/g de miel. Si bien el porcentaje de positividad fue inferior al de otros países, se recomienda no suministrar miel a niños menores de 1 año como prevención de botulismo del lactante

Detección de esporas de Clostridium botulinum en mieles / Detection of Clostridium botulinum in honey

Se examinaron 177 muestras de miel para la detección de Clostridium botulinum; 68 procedentes del comercio, 95 de apiarios envasados en origen, 8 de apiarios rurales para consumo familiar y 6 de establecimientos fraccionadores en las provincias de San Luis y Mendoza. Utilizando el método de dilución-centrifugación, se detectó C. botulinum tipo A en 2 muestras de apiarios rurales de San Luis (1,1 o/o); en una de ellas se logró la recuperación de la cepa y el recuento de esporas fue de 55/g de miel. Si bien el porcentaje de positividad fue inferior al de otros países, se recomienda no suministrar miel a niños menores de 1 año como prevención de botulismo del lactante (AU)

[Detection of Clostridium botulinum spores in honey]. / Detección de esporas de Clostridium botulinum en mieles.

A total of 177 honey samples were examined for Clostridium botulinum, 68 of which were from commercial origin, 8 from small rural producers for family consumption, and the remaining 6 from fractionizing centers in Mendoza and San Luis provinces in Argentina. C. botulinum type A was detected in two samples of rural producer origin (1.1%) by the centrifugation-dilution method. The strain was recovered from one of the samples, obtaining a spore count of 55/g of honey. Even though the positive percentage was lower than that found in other countries, honey consumption by children under one year old should be avoided in order to prevent infant botulism.

[Bacteriologic analysis and detection of Clostridium botulinum spores in honey]. / Análisis bacteriológico e investigación de esporas de Clostridium botulinum en mieles.

The bacteriological analysis and, particularly, the detection of Clostridium botulinum spores from 42 honey samples collected in apiaries of the province of San Luis as well as neighbouring areas of La Pampa, Córdoba and Mendoza, were carried out. Samples were processed by the dilution and centrifugation procedures. For spores detection, culture of the pellets were performed in 2 tubes with cooked meat medium (MCC), one of them warmed up to 80 degrees C for 15 min, and both incubated at 30 degrees C during 7 days. Mice were used to search for toxin in the supernatant. Sediments were also searched for anaerobic bacteria detection in yolk agar plates and in nutritive agar plates for the aerobics. Botulinum toxin type A production was found in one of the MCC cultures. No anaerobic bacteria were isolated. All samples contained Bacillus spp.; 21.4% of the strains, were tentatively classified as B. alvei. A working model for the bacteriological analysis of honey and guides that could be enclosed in publications of official institutions (Figure 1) is proposed.

Análisis bacteriológico e investigación de esporas de Clostridium botulinum en mieles / [Bacteriologic analysis and detection of Clostridium botulinum spores in honey]

The bacteriological analysis and, particularly, the detection of Clostridium botulinum spores from 42 honey samples collected in apiaries of the province of San Luis as well as neighbouring areas of La Pampa, Córdoba and Mendoza, were carried out. Samples were processed by the dilution and centrifugation procedures. For spores detection, culture of the pellets were performed in 2 tubes with cooked meat medium (MCC), one of them warmed up to 80 degrees C for 15 min, and both incubated at 30 degrees C during 7 days. Mice were used to search for toxin in the supernatant. Sediments were also searched for anaerobic bacteria detection in yolk agar plates and in nutritive agar plates for the aerobics. Botulinum toxin type A production was found in one of the MCC cultures. No anaerobic bacteria were isolated. All samples contained Bacillus spp.; 21.4

of the strains, were tentatively classified as B. alvei. A working model for the bacteriological analysis of honey and guides that could be enclosed in publications of official institutions (Figure 1) is proposed.

Análisis bacteriológico e investigación de esporas de Clostridium botulinum en mieles. / [Bacteriologic analysis and detection of Clostridium botulinum spores in honey]

The bacteriological analysis and, particularly, the detection of Clostridium botulinum spores from 42 honey samples collected in apiaries of the province of San Luis as well as neighbouring areas of La Pampa, Córdoba and Mendoza, were carried out. Samples were processed by the dilution and centrifugation procedures. For spores detection, culture of the pellets were performed in 2 tubes with cooked meat medium (MCC), one of them warmed up to 80 degrees C for 15 min, and both incubated at 30 degrees C during 7 days. Mice were used to search for toxin in the supernatant. Sediments were also searched for anaerobic bacteria detection in yolk agar plates and in nutritive agar plates for the aerobics. Botulinum toxin type A production was found in one of the MCC cultures. No anaerobic bacteria were isolated. All samples contained Bacillus spp.; 21.4

of the strains, were tentatively classified as B. alvei. A working model for the bacteriological analysis of honey and guides that could be enclosed in publications of official institutions (Figure 1) is proposed.

[Prevalence of Staphylococcus aureus isolated from subclinical bovine mastitis in dairies of the city of San Luis]. / Prevalencia de Staphylococcus aureus aislados de mastitis subclínica bovina en tambos de la cuenca lechera de la ciudad de San Luis.

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6%) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3%) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5% of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1% were susceptible to chloramphenicol and 53.8% to G penicillin. Sixty three isolates (61.1%) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0%) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9%) as intermediate between B and D; 5 isolates (4.8%) as biotype A (human ecovar) and 1 isolated (0.9%) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2%) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

Prevalencia de Staphylococcus aureus aislados de mastitis subclínica bovina en tambos de la cuenca lechera de la ciudad de San Luis. / [Prevalence of Staphylococcus aureus isolated from subclinical bovine mastitis in dairies of the city of San Luis]

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6

) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3

) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5

of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1

were susceptible to chloramphenicol and 53.8

to G penicillin. Sixty three isolates (61.1

) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0

) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9

) as intermediate between B and D; 5 isolates (4.8

) as biotype A (human ecovar) and 1 isolated (0.9

) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2

) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

Prevalencia de Staphylococcus aureus aislados de mastitis subclínica bovina en tambos de la cuenca lechera de la ciudad de San Luis / [Prevalence of Staphylococcus aureus isolated from subclinical bovine mastitis in dairies of the city of San Luis]

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6

) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3

) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5

of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1

were susceptible to chloramphenicol and 53.8

) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0

) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9

) as intermediate between B and D; 5 isolates (4.8

) as biotype A (human ecovar) and 1 isolated (0.9

) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2

) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

Prevalencia de Staphylococcus aureus aislados de mastitis subclínica bovina en tambos de la cuenca lechera de la ciudad de San Luis / [Prevalence of Staphylococcus aureus isolated from subclinical bovine mastitis in dairies of the city of San Luis]

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6

) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3

) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5

of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1

were susceptible to chloramphenicol and 53.8

) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0

) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9

) as intermediate between B and D; 5 isolates (4.8

) as biotype A (human ecovar) and 1 isolated (0.9

) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2

) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

Prevalencia de Staphylococcus aureus aislados de mastitis subclínica bovina en tambos de la cuenca lechera de la ciudad de San Luis. / [Prevalence of Staphylococcus aureus isolated from subclinical bovine mastitis in dairies of the city of San Luis]

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6

) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3

) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5

of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1

were susceptible to chloramphenicol and 53.8

to G penicillin. Sixty three isolates (61.1

) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0

) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9

) as intermediate between B and D; 5 isolates (4.8

) as biotype A (human ecovar) and 1 isolated (0.9

) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2

) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

[1st isolation of strains of Staphylococcus aureus producing toxic shock syndrome toxin 1 in food handlers in Argentina]. / Primer aislamiento de cepas de Staphylococcus aureus productores de toxina del síndrome de shock tóxico-1 en manipuladores de alimentos en Argentina.

Thirty nine milk handlers from a factory of dairy products in the Province of Buenos Aires were examined for their nasal carriage of S. aureus strains capable of producing toxic-shock-syndrome toxin-1 (TSST-1). In addition, chance samples of handled foods, crude milk and milky fermented derivates (MFD) were studied. Strain isolation was made on Mannitol Salt Agar and on Baird-Parker Agar. Typical colonies were identified by their biochemical properties. Cultures that were found to be S. aureus were selected for analysis of the TSST-1 production. Eight milk handlers (20.5%) were carriers of S. aureus strains. Seven isolates (87.5%) were classified as biotype A (human ecovar) and 1(12.5%) was classified as biotype B (swine and poultry ecovar). Three out of 8 S. aureus biotype A isolates (37.5%), produced TSST-1. Taking into account the number of milk food handlers sampled (39), the carried rate of toxigenic strains was 7.6%. Three S. aureus strains were isolated from crude milk; 1(33.3%) was classified as biotype B and 2(66.6%) as biotype C (cattle and sheep ecovar). Thirteen S. aureus strains were isolated from MDF; 5(38.0%) were classified as biotype A, 1(7.7%) as belonging to biotype B and 7(53.8%) as belonging to biotype C. None of them had the ability to produce TSST-1.

Primer aislamiento de cepas de Staphylococcus aureus productores de toxina del síndrome de shock tóxico-1 en manipuladores de alimentos en Argentina. / [1st isolation of strains of Staphylococcus aureus producing toxic shock syndrome toxin 1 in food handlers in Argentina]

Thirty nine milk handlers from a factory of dairy products in the Province of Buenos Aires were examined for their nasal carriage of S. aureus strains capable of producing toxic-shock-syndrome toxin-1 (TSST-1). In addition, chance samples of handled foods, crude milk and milky fermented derivates (MFD) were studied. Strain isolation was made on Mannitol Salt Agar and on Baird-Parker Agar. Typical colonies were identified by their biochemical properties. Cultures that were found to be S. aureus were selected for analysis of the TSST-1 production. Eight milk handlers (20.5

) were carriers of S. aureus strains. Seven isolates (87.5

) were classified as biotype A (human ecovar) and 1(12.5

) was classified as biotype B (swine and poultry ecovar). Three out of 8 S. aureus biotype A isolates (37.5

), produced TSST-1. Taking into account the number of milk food handlers sampled (39), the carried rate of toxigenic strains was 7.6

. Three S. aureus strains were isolated from crude milk; 1(33.3

) was classified as biotype B and 2(66.6

) as biotype C (cattle and sheep ecovar). Thirteen S. aureus strains were isolated from MDF; 5(38.0

) were classified as biotype A, 1(7.7

) as belonging to biotype B and 7(53.8

) as belonging to biotype C. None of them had the ability to produce TSST-1.

[Determination of the sanitary quality and detection of Salmonella spp and Yersinia enterocolitica in ice cream]. / Determinación de la calidad higiénica e investigación de Salmonella spp y Yersinia enterocolítica en helados.

In order to determine the sanitary quality of ice-creams and the presence of pathogenic or potentially pathogenic species of Salmonella and Yersinia enterocolitica, 50 samples from 5 different industrial and semi-industrial producers in San Luis (Argentine) were examined. The enumeration of coliforms was positive for all the samples with values less than or equal to 20/g. Fourteen per cent of the samples were positive for the investigation of Staphylococcus aureus in 1 g. For the plates enumeration 12.0% of the samples gave less than 10 u.f.c./g, 4.0% between 101 and 1000 and 4.0% between 1001 and 10,000. Fifteen strains were isolated, 26.6% biotype A (human ecovar) and the others biotype C (bovine ecovar). All of them were susceptible to chloramphenicol, cephalosporin and erythromycin; 46.6% to penicillin G and ampicillin; 93.3% to kanamycin (6.6% intermediate ones = I); 73.3% to methicillin (26.6% I); 86.6% to tetracycline (13.3% I). Six per cent of the samples over came the acceptability limit for S. aureus. Salmonella spp was not isolated. In 4.0% of the samples Y. enterocolitica were isolated, one of them typified as B1; 0:3, 50, 51, Lis Xz. The latter, isolated in samples with values of coliforms inferior to the limit fixed by some legislations, suggests a post elaboration contamination.

Determinación de la calidad higiénica e investigación de Salmonella spp y Yersinia enterocolítica en helados. / [Determination of the sanitary quality and detection of Salmonella spp and Yersinia enterocolitica in ice cream]

In order to determine the sanitary quality of ice-creams and the presence of pathogenic or potentially pathogenic species of Salmonella and Yersinia enterocolitica, 50 samples from 5 different industrial and semi-industrial producers in San Luis (Argentine) were examined. The enumeration of coliforms was positive for all the samples with values less than or equal to 20/g. Fourteen per cent of the samples were positive for the investigation of Staphylococcus aureus in 1 g. For the plates enumeration 12.0

of the samples gave less than 10 u.f.c./g, 4.0

between 101 and 1000 and 4.0

between 1001 and 10,000. Fifteen strains were isolated, 26.6

biotype A (human ecovar) and the others biotype C (bovine ecovar). All of them were susceptible to chloramphenicol, cephalosporin and erythromycin; 46.6

to penicillin G and ampicillin; 93.3

to kanamycin (6.6

intermediate ones = I); 73.3

to methicillin (26.6

I); 86.6

to tetracycline (13.3

I). Six per cent of the samples over came the acceptability limit for S. aureus. Salmonella spp was not isolated. In 4.0

of the samples Y. enterocolitica were isolated, one of them typified as B1; 0:3, 50, 51, Lis Xz. The latter, isolated in samples with values of coliforms inferior to the limit fixed by some legislations, suggests a post elaboration contamination.