Vanerli Beloti

Listeria monocytogenes: Occurrence in beef and identification of the main contamination points in processing plants.

This study aimed to establish the occurrence of Listeria spp., especially L. monocytogenes and its main serotypes, in beef and processing plants. A total of 443 samples were obtained from equipment, installations and products from 11 meat processing establishments from Paraná state, Brazil. All samples were analyzed using USDA methodology for Listeria spp. detection, followed by species identification. The occurrence of Listeria spp. in the samples was 38.1% of which 51.4% were from equipment, 35.4% from installations and 30.2% from products. The identified species were: L. monocytogenes (12.6%), L. innocua (78.4%), L. seeligeri (1.2%), L. welshimeri (7.2%) and L. grayi (0.6%). The identified serotypes of L. monocytogenes were 1/2a and 4b. The results demonstrate the significance of equipment and installations as sources of contamination by Listeria spp. and L. monocytogenes in the processing of beef and meat products.

Hazards in non-pasteurized milk on retail sale in Brazil: prevalence of Salmonella spp, Listeria monocytogenes and chemical residues

A instabilidade do mercado de leite no Brasil forca pequenos produtores de leite a procurar alternativas de comercio de sua producao, o que inclui a venda de leite cru para individuos que dao preferencia a esse tipo de leite. Considerando a importância desse mercado e os conhecidos riscos a saude que o consumo de leite cru pode representar, este estudo avaliou a qualidade microbiologica e a presenca de Listeria monocytogenes, Salmonella spp., residuos de cloretos, antimicrobianos e inseticidas (organofosforados e carbamatos) em leite cru produzido em 210 propriedades leiteiras localizadas em quatro importantes estados produtores de leite no Brasil (Parana, Sao Paulo, Minas Gerais e Rio Grande do Sul). Em 66% das propriedades selecionadas, a ordenha era manual. Em 33% a ordenha era semi-automatica (ordenha mecânica balde ao pe) e em apenas 1% o sistema de ordenha e armazenamento era totalmente mecânico (sistema fechado). Todas as amostras de leite cru foram negativas para L. monocytogenes, Salmonella spp e residuos de cloretos. As contagens de aerobios mesofilos foram superiores a 105 UFC/mL em 75,7% das amostras. Em 80,4%, as contagens de coliformes foram superiores a 102 UFC/mL. Escherichia coli foi detectada em 36,8% das amostras. Inseticidas e residuos de antibioticos foram observados em 74,4% e 11,5% das amostras, respectivamente. Niveis inaceitaveis de microrganismos indicadores de higiene, inseticidas e residuos de antibioticos foram considerados fatores de risco mais importantes que os dois patogenos estudados.

Listeria monocytogenes and Salmonella spp. in Raw Milk Produced in Brazil: Occurrence and Interference of Indigenous Microbiota in their Isolation and Development

This study aimed to verify the occurrence of Listeria monocytogenes and Salmonella spp. in raw milk produced in Brazil. On account of the poor microbiological quality of this product, possible interference from the indigenous microbiota in these pathogens was also evaluated. Two‐hundred and ten raw milk samples were collected in four important milk‐producing areas in Brazil, tested for L. monocytogenes and Salmonella spp. presence, and for enumeration of indicator microorganisms: mesophilic aerobes, total coliforms and Escherichia coli. The interference of the indigenous microbiota in the isolation procedures was also tested, as well the frequency of naturally occurring raw milk strains with antagonistic activity against both pathogens. The pathogens were not isolated in any raw milk sample, but poor microbiological quality was confirmed by the high levels of indicator microorganisms. When present at high levels, the indigenous microbiota generated an evident interference in the methodologies of L. monocytogenes and Salmonella spp. isolation, mainly when the pathogens appeared at low levels. Three‐hundred and sixty raw milk strains were tested for antagonistic activity against both pathogens, and 91 (25.3%) showed inhibitory activity against L. monocytogenes and 33 (9.2%) against Salmonella spp. The majority of the antagonistic strains were identified as Lactic Acid Bacteria species, mainly Lactococcus lactis subsp. lactis and Enterococcus faecium, known by antimicrobial substance production.

Resíduos de antibióticos em leite cru de quatro regiões leiteiras no Brasil

Antimicrobial residues present in milk can have many adverse effects for public health and for the dairy industry. The aim of this study is to evaluate the presence of antibiotics using the Charm-test™ kit (b-lactams and sulfonamides, mainly) in 210 raw milk samples collected in four different milk-producing areas in Brazil: 47 in Vicosa - MG, 50 in Pelotas - RS, 63 in Londrina - PR and 50 in Botucatu - SP. Antibiotic residues were detected in 24 samples (11.4%). Among them, 13 (20.6%) were from Londrina - PR, 4 (8.0%) from Botucatu - SP, 4 (8.5%) from Vicosa - MG, and 3 (6.0%) from Pelotas - RS. Despite being qualitative results only, it is evident that antibiotics may be an important chemical hazard in milk produced in Brazil.

Leite cru de quatro regiões leiteiras brasileiras: perspectivas de atendimento dos requisitos microbiológicos estabelecidos pela Instrução Normativa 51

Evidencias que o leite produzido e consumido no Brasil nem sempre apresenta a qualidade desejada tem gerado a discussao e desenvolvimento de novas politicas de incentivo a producao leiteira, resultando no desenvolvimento do Programa Nacional de Melhoria da Qualidade do Leite. Em complementacao, em 2002 o Ministerio da Agricultura publicou a Instrucao Normativa 51 (IN51), com importantes inovacoes em relacao a conservacao e transporte do leite cru, alem de estabelecimento de um padrao de qualidade para esse tipo de leite (106 UFC/mL), a ser implantado em diferentes prazos nas diferentes regioes do pais, a partir de 2005. O presente trabalho teve como objetivo verificar se o leite cru produzido em quatro areas de quatro estados produtores de leite no Brasil estaria, nesse momento, em condicoes de cumprir o estabelecido na IN 51, especialmente quanto ao atendimento dos padroes microbiologicos previstos. Amostras de leite cru, coletadas em 210 diferentes propriedades nas regioes de Vicosa, MG (47), Pelotas, RS (50), Londrina, PR (63) e Botucatu, SP (50), foram analisadas quanto aos niveis de contaminacao por aerobios mesofilos, utilizando o PetrifilmTM AC. Parcela significativa das amostras (48,6%) apresentaram contagens acima do determinado pela IN51, sendo 21,3% na regiao de Vicosa (MG), 56,0% na regiao de Pelotas (RS), 47,6% na regiao de Londrina (PR) e 68,0% na regiao de Botucatu (SP). Considerando as diferencas de cada regiao, foi possivel observar a importância da refrigeracao na conservacao e transporte da producao, bem como da implantacao de boas praticas e assistencia tecnica nas propriedades. Os resultados obtidos permitem concluir que a adequacao as normas estabelecidas pela IN51 pode ser mais dificil em algumas regioes do que em outras, sendo fundamental a adocao da refrigeracao na conservacao e no transporte da producao, e de programas regionais de assistencia a produtores leiteiros.

Quality of pasteurized milk influences the performance of ready-to-use systems for enumeration of aerobic microorganisms

Three grades of pasteurized milk (A, B and C) are currently available in the Brazilian market. Due to differences in the hygienic and sanitary conditions during production, the resulting load of viable bacteria in each type of pasteurized milk is different, being A<B<C. The influence of the microbiological quality on the performance of two rapid and easy-to-perform analytical systems (Petrifilm™ AC and Simplate™ TPC plates) for enumeration of total viable bacteria in pasteurized milk was evaluated. The standard plate count procedure, using standard methods agar (SMA), was used as the reference method. A clear relationship between milk grade and performance of Petrifilm™ AC was observed: regression analysis indicated that correlation coefficient (r) values were 0.852, 0.770 and 0.693 for milk grades A, B and C, respectively, and 0.878 when samples were evaluated globally. For Simplate™ TPC plates, this relationship was less evident, because r values correlating counts in these plates and SMA were too low.

Screening and enumeration of lactic acid bacteria in milk using three different culture media in Petrifilm™ Aerobic Count plates and conventional pour plate methodology

This study aimed to compare Petrifilm Aerobic Count (AC) plates and the conventional pour plate methodology using de Mann-Rogosa-Sharpe (MRS), Kang-Fung (KF) and Kang-Fung-Sol (KFS) culture media for screening and enumeration of lactic acid bacteria (LAB) in milk. Suspensions of 10 LAB species in reconstituted powder skim milk and 30 raw milk samples, without experimental inoculation, were tested. For selective enumeration, all samples were previously diluted in MRS, KF and KFS broths and then plated in Petrifilm AC and conventional pour plate methodology, using the same culture media with added agar. All plates were incubated at 37 degrees C for 48 h in anaerobic conditions. Differences in the counts were observed only for raw milk samples using KFS in conventional methodology, when compared with the counts obtained from MRS and KF (P0.05). The results showed excellent correlation indexes between both methodologies using the three culture media for LAB suspensions (r=0.97 for MRS, KF and KFS). For raw milk samples, the correlation indexes were excellent (r=0.97, for MRS) and good (r=0.84 for KF, and r=0.82 for KFS), showing some interference in Petrifilm AC when supplements were added, especially lactic acid. These results indicate the possibility of using Petrifilm AC plates for enumeration of LAB in milk, even with the use of selective supplements.

Identification of main contamination points by hygiene indicator microorganisms in beef processing plants

The microbiological quality of beef and meat products is strongly influenced by the conditions of hygiene prevailing during their production and handling. Without proper hygienic control, the environment in slaughterhouses and butcher shops can act as an important source of microbiological contamination. To identify the main points of microbiological contamination in the beef processing chain, 443 samples of equipment, installations and products were collected from 11 establishments (1 slaughterhouse and 10 butcher shops) located in the state of Parana, Brazil. The microbiological quality of all the samples was evaluated using Petri dishes to obtain counts of mesophilic aerobes (AC), total coliforms, Escherichia coli (EC), yeasts and molds (YM). The main contamination points identified in butcher shops, in decreasing order, were stainless steel boxes, beef tenderizers, grinders, knives, mixers, sausage stuffers, plastic boxes, floors and drains. In the slaughterhouse, these points were sausage stuffers, platforms, floors and drains. The most severely contaminated products were fresh sausages and ground beef. This information about the main points of microbiological contamination in the beef processing chain is expected to aid professionals responsible for hygiene in similar establishments to set up proper hygienic procedures to prevent or reduce microbiological contamination of beef and meat products.

Organofosforados e carbamatos no leite produzido em quatro regiões leiteiras no Brasil: ocorrência e ação sobre Listeria monocytogenes e Salmonella spp.

Chemical residues may be present in foods due to contamination in early stages of production, posing a potential risk to consumers. Organophosphates and carbamates are used in the control of parasites in animals and may generate residues in foods derived from these animals, like milk. This study aimed to survey the presence of these two pesticides in raw milk samples collected in four important milk-producing regions in Brazil and observe any possible relationship between presence of these compounds and the previously reported absence of Listeria monocytogenes e Salmonella spp. in the same milk samples. Organophosphates and/or carbamates were detected in 196 (93.8%) out of 209 samples. For evaluation of the interference of these products on detection of L. monocytogenes and Salmonella spp., 28 milk samples containing these pesticides were boiled for 10 minutes, added of the pathogens, and their multiplication was monitored during storage at 4 °C and 25 °C. No significant differences (p < 0.05) were observed in the growth of these pathogens in the milk samples when compared to negative controls, indicating absence of interference of the compounds on the detection of L. monocytogenes or Salmonella spp. However, the high frequency of raw milk samples containing organophosphates and/or carbamates poses a potential health problem to the consumers, even after heat treatment of the milk.

Acid-base balance of dairy cows and its relationship with alcoholic stability and mineral composition of milk

This study aimed to associate the occurrence of acid-base disorders with the alcoholic stability of milk from animals in the field, and to evaluate differences between the mineral composition of milk that was both stable and unstable in alcohol. The sample comprised 96 dairy cows, where the milk and blood of each corresponding animal was collected. The mineral composition of stable and unstable milk in alcohol was different and may be related to acid-base disturbances. The average amount of phosphate was lower in the milk that was unstable in alcohol, while potassium was greater. Frequency of the alcoholically unstable milk cases was higher in the cows with acid-base disturbances. Respiratory alkalosis was the disorder that was most observed.