RESUMO
OBJECTIVE: To determine the effect of refrigeration time and temperature on Salmonella cell numbers on inoculated chicken carcasses and their transfer to a plastic cutting board. METHODS AND RESULTS: The survival of Salmonella on chicken skin and the transfer to a plastic cutting board when exposed to different refrigeration temperatures (2, 6 or 8 degrees C) for 9 days were the two main issues on which this work focused. Two scenarios were carried out to ascertain these effects: carcasses treated with a decontaminating acetic acid solution and untreated carcasses. All of the contaminated carcasses remained contaminated after 9 days of refrigeration. However, on untreated samples, while Salmonella numbers increased almost 1.5 log at 8 degrees C, the pathogen numbers decreased about 1 log at 2 and 6 degrees C. On acid-treated samples, cell numbers slightly decreased at all of the temperatures studied. Temperature did not affect salmonellae transfer to the cutting board, but time did. Acid decontamination increased cell numbers transferred to the cutting board compared with untreated samples. CONCLUSION: Proper refrigeration at low temperatures did not allow Salmonella numbers to rise, regardless of which carcasses had been, or had not been, acid treated. Despite the fact that the rate of transfer was not affected by temperature, the acid treatment detached Salmonella cells from the chicken skin and, therefore, the probability of greater cross-contamination should be studied further. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study may provide better information about the refrigeration conditions for fresh chicken storage and also determine if these, along with acetic acid decontamination of broiler chicken, would affect the pathogen transfer to a cutting board.
Assuntos
Manipulação de Alimentos/métodos , Carne/microbiologia , Refrigeração/métodos , Salmonella/fisiologia , Animais , Galinhas , Temperatura Baixa , Viabilidade Microbiana , Fatores de TempoRESUMO
AIMS: A comparison of Enterobacteriaceae, coliform and Escherichia coli counts in chicken carcasses with and without visible faecal contamination was conducted to evaluate the role of contamination as a vehicle for generic E. coli, coliform and other enterobacteria contaminating broiler chicken carcasses when processed under routine commercial operations. METHODS AND RESULTS: Samples were removed from the processing line immediately after evisceration, inside-outside shower and chilling for microbiological analysis. After evisceration, mean counts were significantly different only for E. coli (P < or = 0.05) in chicken carcasses with and without visible faecal contamination. While the spray wash practice was not efficient enough for complete removal of the visible contamination from carcasses, leading to microbiological reduction percentages lower than expected, 25 ppm chlorinated water chilling did reduce the contamination level considerably in all samples. CONCLUSIONS: Carcasses with and without visible faecal contamination harboured E. coli and other potentially hazardous enterobacteria. E. coli was the predominant strain isolated in all samples, Enterobacter cloacae being next most frequent. SIGNIFICANCE AND IMPACT OF THE STUDY: The zero tolerance of visible faecal contamination requirement alone is not sufficient to assure safety and to improve the microbial quality of carcasses.
Assuntos
Matadouros , Enterobacteriaceae/isolamento & purificação , Fezes/microbiologia , Microbiologia de Alimentos , Animais , Bile/microbiologia , Galinhas/microbiologia , Contagem de Colônia Microbiana , Escherichia coli/isolamento & purificação , Manipulação de Alimentos/métodosRESUMO
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.
Assuntos
Bactérias/isolamento & purificação , Manipulação de Alimentos/métodos , Serviços de Alimentação/normas , Argentina , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Enterobacteriaceae/isolamento & purificação , Microbiologia de Alimentos , Paladar , TemperaturaRESUMO
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.
Assuntos
Mastite Bovina/microbiologia , Pseudomonas aeruginosa/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Streptococcus agalactiae/isolamento & purificação , Animais , Antibacterianos/farmacologia , Bovinos , Resistência Microbiana a Medicamentos , Feminino , Leite/microbiologiaRESUMO
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.
RESUMO
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.
