Brazilian legislation allows the manufacture of raw milk cheese with a maturation exceeding 60 days at room temperature above 5°C, but there is a lack of solid scientific evidence on the efficacy of this maturation process in inactivating important pathogens that may be present in milk, such as Mycobacterium bovis and Brucella abortus. Thus, the objectives of this study were to produce parmesan-type cheese experimentally contaminated with M. bovis and B. abortus and evaluate the survival of these pathogens along 2-month maturation. Parmesan-type cheese was manufactured in the laboratory using whole pasteurized milk with or without inoculation with M. bovis (SB1033) or B. abortus (1119-3) and matured at 18°C for up to 63 days. M. bovis was inoculated in Stonebrink-Leslie medium supplemented with antibiotics and incubated at 37°C for 45 days, and B. abortus was incubated in Farrel medium at 36°C for 3 days. The average D18°C value, weighted by variance, was 37.5 ± 5.3 days for M. bovis and 5.9 ± 0.7 days for B. abortus. The average physicochemical parameters in the cheese at the end of the study were as follows: pH = 4.89, water activity = 0.976, and moisture percentage = 43.1%. The pH might have contributed to the reduction in the population of B. abortus but seems not to have influenced the population of M. bovis. We conclude that the duration of the maturation process influences the size of the surviving populations of M. bovis and B. abortus, and that the shortening of the maturation duration might not ensure a decline in pathogen levels to safe levels. Thus, complementary studies considering the effect of several other technological aspects on the survival of these pathogens are required, including the effect of the lactic acid bacterial population, salt content, and temperature of maturation. ; A legislação brasileira permite a fabricação queijos de leite cru com maturação superior a 60 dias em temperatura acima de 5°C, mas falta evidência científica sólida sobre a eficácia do processo de maturação na inativação de importantes patógenos que podem estar presentes no leite, como o Mycobacterium bovis e a Brucella abortus. Assim, os objetivos desse estudo foram produzir o queijo tipo parmesão experimentalmente contaminado com M. bovis e B. abortus e avaliar a sobrevivência desses patógenos ao longo de 2 meses de maturação. Queijo do tipo parmesão foi fabricado em laboratório com leite pasteurizado integral com ou sem inoculo de M. bovis (SB1033) ou B. abortus (1119-3) e maturado a 18°C por até 63 dias. M. bovis foi semeado em meio Stonebrink-Leslie, acrescido de antibióticos, e incubado a 37°C por 45 dias e a B. abortus foi semeada em meio Farrel a 36°C por 3 dias. O valor D18°C médio, ponderado pela variância, foi de 37,5 ± 5,3 dias para o M. bovis e de 5,9 ± 0,7 dias para a B. abortus. Os parâmetros físico-químicos médios do queijo no final do estudo foram como se segue: pH = 4,89, atividade de água = 0,976 e umidade percentual = 43,1%. O pH pode ter contribuído para redução da população de B. abortus mas parece não ter influenciado a população de M. bovis. Concluiu-se que a duração do processo de maturação influencia o tamanho da população sobrevivente de M. bovis e de B. abortus e que o encurtamento do período de maturação pode não garantir um declínio desses patógenos para níveis seguros. Assim, estudos complementares que considerem o efeito de vários outros aspectos tecnológicos na sobrevivência desses patógenos são necessários, incluindo o efeito da população de bactérias ácido láticas, teor de sal e temperatura de maturação.
This study was conducted to characterize the epidemiology of bovine brucellosis in the state of Pernambuco, Brazil. The state was divided into three regions, and in each region, approximately 300 properties were randomly sampled. From these selected properties, a pre-established number of animals were randomly selected and blood serum samples were obtained. A total of 3,901 animals were selected from 900 properties. For each selected property, an epidemiological questionnaire was administered to assess the type of farming, the animal husbandry practices and the sanitary practices that could be associated with the presence of brucellosis infection. The testing protocol consisted of screening the samples with a buffered acidified plate antigen test and retesting the positive samples with a complement fixation test (CF). One positive animal was enough to define an infected herd. The prevalence rates of infected herds and animals in the state were 4.5% [3.2; 6.4%] and 1.4% [0.7; 2.7%], respectively. By region, the prevalence rates of infected herds and animals, respectively, were as follows: Zona da Mata, 3.3% [1.8; 6.1%] and 1.7% [0.5; 3.0%]; Agreste, 7.4% [4.9; 10.9%] and 1.9% [0.8; 3.0%]; and Sertão, 1.3% [0.5; 3.5%] and 0.7% [0.0; 1.6%]. Flooded pastures (OR = 2.86 [1.37; 6.42]) and the presence of 13 or more females in the herd (3rd quartile) (OR = 2.65 [1.19; 5.89]) were identified as risk factors. The existence of veterinary care emerged as a protective factor against bovine brucellosis in the state of Pernambuco (OR = 0.24 [0.10; 0.58]).
A cross sectional study was carried out between May and November 2011 to investigate the epidemiological situation of bovine tuberculosis (bTB) in the state of São Paulo, Brazil. The state was divided into seven regions. Three hundred farms from each region, with reproductive activity, were randomly chosen and included as primary sample units. A fixed number of bovine females, older than 2 years of age, were randomly selected and tested, using the comparative cervical tuberculin test. An epidemiological questionnaire based survey was conducted in the selected farms. Our results show that in the state of São Paulo, the apparent prevalence of positive farms was 9% (95% confidence interval, 95% CI = 7.8 – 10.5%). The prevalence in the individual regions varied between 3.5% (95% CI = 1.7 ? 6.8%) and 13.9% (95% CI = 10.2 – 18.8%). The apparent prevalence of positive animals in the state was 1.3% (95% CI = 0.9 – 1.7%) and varied from 0.3% (95% CI = 0.2 – 0.6%) to 2.5% (95% CI = 1.4 – 4.5%) in the regions. The risk factors associated with tuberculosis in the state were (i) number of adult females in a herd is ? 24 (Odds ratio, OR = 1.91, 95% CI = 1.32 – 2.75), (ii) type of farm enterprise (dairy: OR = 2.70, 95% CI = 1.40 – 5.21; mixed: OR = 2.03, 95% CI = 1.08 – 3.82), (iii) milking process (milking parlor: OR = 4.12, 95% CI = 1.46 – 11.64; portable milking machine: OR = 2.94, 95% CI = 1.42 – 6.09), and (iv) pasture sharing (OR = 1.58, 95% CI = 1.07 – 2.33). The state of São Paulo should implement a structured surveillance system to detect and mitigate the disease. Further, an efficient animal health education program, which encourages the farmers to test replacement animals for bTB prior to introduction in their herds and to avoid pasture sharing with farms of unknown sanitary conditions should also be implemented.
The epidemiological situation of bovine tuberculosis was studied from October 2014 to August 2015 in the state of Tocantins, a traditional beef exporter. The state was divided into five regions and the farms were randomly selected in each region. A predetermined number of animals was randomly selected and diagnosed using the Comparative Cervical Tuberculin Test. A total of 11,926 animals from 757 farms were tested. Animals with inconclusive test results were retested with the same diagnostic procedure at least 60 days later. The prevalence of infected herds in the state was 0.16% [0.02-1.15] and the prevalence of infected animals 0.009% [0.001-0.063]. Only one positive animal was detected in the Araguaína region. The state of Tocantins has a very low prevalence of bovine tuberculosis and, therefore, should evaluate the need of structuring a surveillance system to eradicate the disease.
A cross-sectional study on the epidemiological situation of bovine brucellosis was carried out in the state of Tocantins to evaluate the effectiveness of its vaccination program. The state was divided into five regions, and a predetermined number of farms was randomly selected in each one. Females aged 24 months or older were randomly selected in each farm and diagnosed with brucellosis by serial serology (AAT and 2-ME). A total of 6,846 animals from 756 farms were examined. The prevalence of seropositive herds in the state was 6.42% [CI95%: 4.76-8.62], and the prevalence of seropositive animals was 2.21% [CI95%: 1.05-4.01]. The prevalence of seropositive herds was homogeneously distributed among regions. The 2002/2003 study estimated the prevalence of seropositive herds in the state to be 21.22% [CI95%: 19.33-23.11]. In conclusion, the vaccination program implemented in Tocantins, reaching vaccination coverage above 70% as of 2010, significantly reduced the prevalence of seropositive herds. Thus, continuing the vaccination program in the state is recommended, preferably increasing the quality of the processes involved, from commercialization to inoculation in animals, since immunization remains the most effective means to reduce the prevalence of brucellosis. In addition, animal replacement remains a major risk factor for bovine brucellosis in Tocantins since 20022003; therefore, the state must implement a strong health education program explaining to farmers the importance of testing animals for brucellosis before introducing them into their herds.
