ABSTRACT
The purpose of this study was to evaluate the microbiological and sensory quality as well as the safety of ready-to-eat (RTE) cooked foods prepared in and distributed from a centralized kitchen to schools in Argentina. A total of 101 cooked food samples delivered as hot RTE cooked foods (group A) and as RTE cooked foods at room temperature (group B) and 140 surface swab environment samples were collected from February to November 1999. Petrifilm plates were used for aerobic (PAC), coliform (PCC), and Escherichia coli (PEC) counts. Standard methods were used to determine Enterobacteriaceae (EntC) and thermotolerant coliform counts (TCC). Samples were also tested for the presence of Salmonella spp., Staphylococcus aureus, Bacillus cereus, and Clostridium perfringens. Food temperatures just before samples were put into containers ranged from 80 to 98 degrees C and from 28 to 32 degrees C for group A and group B, respectively. For group A food samples, PAC ranged from 1.04 to 3.50 log CFU/g, and PCC, PEC, TCC, and EntC were not detected. For group B food samples, PAC ranged from 3.63 to 6.48 log CFU/g, PCC ranged from 1.90 to 5.36 log CFU/g, TCC ranged from 1.30 to 3.95 log CFU/g, and EntC ranged from 3.60 to 5.46 log CFU/g. Of the foodborne pathogens, only B. cereus was isolated (63.4% of samples) in both food groups (<4 log CFU/g). The microbiological and sensory quality and the safety of group A foods were satisfactory. Large numbers of PAC and EntC detected in group B foods show that better control is needed to avoid potential foodborne diseases.
Subject(s)
Bacteria/isolation & purification , Food Handling/methods , Food Services/standards , Argentina , Colony Count, Microbial , Consumer Product Safety , Enterobacteriaceae/isolation & purification , Food Microbiology , Taste , TemperatureABSTRACT
Washing disinfection with chlorine is widely used to reduce the initial microbiological load during the preparation of minimally processed vegetables. The effects of initial concentration of chlorine, time and the liquid volume:produce weight ratio on the reduction of Salmonella counts on inoculated spinach were evaluated using response surface methodology. Initial chlorine concentration, time and the interaction between them had a significant effect on reduction of Salmonella populations. However, the liquid volume:produce weight ratio did not have significant effects. The highest Salmonella reduction was around 1.2-1.4 log at 125 ppm during 8 min regardless of the water:produce ratio. According to the results, chlorination reduced Salmonella hadar population, but the complete elimination from the produce was not achieved.
Subject(s)
Chlorine/pharmacology , Disinfection/methods , Food Handling , Salmonella/growth & development , Spinacia oleracea/microbiology , Colony Count, Microbial , Disinfectants , Food Microbiology , Sodium Hypochlorite , WaterABSTRACT
Chicken breasts with skin were packaged either in air, under vacuum or in modified atmospheres of (i) 30% CO2/70% N2 and (ii) 70% CO2/30% N2. After 3, 7, 14 and 21 days of storage at 4 degrees C, the samples were evaluated for spoilage microbial growth, odour and overall aspect. As expected, pseudomonads grew well in air or under vacuum, but growth was suppressed in both types of modified atmosphere packaging (MAP). However, growth of lactobacilli, Enterobacteriaceae and Brochothrix thermosphacta was not inhibited in MAPs. Modified atmosphere packaging (ii) extended shelf-life up to 21 days compared to 5 days for air-packed samples.
Subject(s)
Chickens/microbiology , Food Packaging , Food Preservation , Poultry Products/microbiology , Animals , Argentina , Enterobacteriaceae/isolation & purification , Gases , Lactobacillus/isolation & purification , Pseudomonas/isolation & purification , Refrigeration , TemperatureABSTRACT
A study of 320 samples of mammary quarters from cows in 40 dairy farms around Santa Fe city during 1977-1978 was made. The samples were selected based on clinical examination and California Mastitis Test (GMT). High percentage of subclinical mastitis was found. The etiological agents most frequently isolated were Staphylococcus aureus (54,1%), Streptococcus agalactiae (23.4%) and Pseudomonas aeruginosa (13,2%). A winter increment of S. aureus (48,1%) and P. aeruginosa (3,7% and 22,5%) was observed. But S. agalactiae did not experiment considerable variation (26,8% and 20% throughout the year. The sensitivity to antibiotics of some strains decreased in winter specially in S. aureus and P. aeruginosa (61,5% and 38,9%), and some biochemical properties related with their virulence increased. Penicillin in milk was not detected, but the levels of contamination by non specific inhibitory substances were very high (40%). Besides it was found a great contamination with aerobic sporeforming bacteria in these samples, being Bacillus coagulans (59,1%), B. polymyxa (26,1%) and B. sphaericus (9,5%) the most frequent.
Subject(s)
Mastitis, Bovine/microbiology , Pseudomonas aeruginosa/isolation & purification , Staphylococcus aureus/isolation & purification , Streptococcus agalactiae/isolation & purification , Animals , Anti-Bacterial Agents/pharmacology , Cattle , Drug Resistance, Microbial , Female , Milk/microbiologyABSTRACT
A study of 320 samples of mammary quarters from cows in 40 dairy farms around Santa Fe city during 1977-1978 was made. The samples were selected based on clinical examination and California Mastitis Test (GMT). High percentage of subclinical mastitis was found. The etiological agents most frequently isolated were Staphylococcus aureus (54,1
) and Pseudomonas aeruginosa (13,2
). A winter increment of S. aureus (48,1
) and P. aeruginosa (3,7
throughout the year. The sensitivity to antibiotics of some strains decreased in winter specially in S. aureus and P. aeruginosa (61,5
), and some biochemical properties related with their virulence increased. Penicillin in milk was not detected, but the levels of contamination by non specific inhibitory substances were very high (40
). Besides it was found a great contamination with aerobic sporeforming bacteria in these samples, being Bacillus coagulans (59,1
) and B. sphaericus (9,5
) the most frequent.
ABSTRACT
A study of 320 samples of mammary quarters from cows in 40 dairy farms around Santa Fe city during 1977-1978 was made. The samples were selected based on clinical examination and California Mastitis Test (GMT). High percentage of subclinical mastitis was found. The etiological agents most frequently isolated were Staphylococcus aureus (54,1
), Streptococcus agalactiae (23.4
) and Pseudomonas aeruginosa (13,2
). A winter increment of S. aureus (48,1
) and P. aeruginosa (3,7
and 22,5
) was observed. But S. agalactiae did not experiment considerable variation (26,8
and 20
throughout the year. The sensitivity to antibiotics of some strains decreased in winter specially in S. aureus and P. aeruginosa (61,5
and 38,9
), and some biochemical properties related with their virulence increased. Penicillin in milk was not detected, but the levels of contamination by non specific inhibitory substances were very high (40
). Besides it was found a great contamination with aerobic sporeforming bacteria in these samples, being Bacillus coagulans (59,1
), B. polymyxa (26,1
) and B. sphaericus (9,5
) the most frequent.
