Recovery of Brucella in raw milk Minas artisanal cheese approved for consumption by official inspection agency in Brazil: assessment of prevalence and risk factors through One Health integrated approaches

BACKGROUND

Minas artisanal cheese (MAC) from the Serro region is a Brazilian intangible cultural heritage. Produced from raw milk, it may carry zoonotic pathogens such as Brucella. This study included a randomized survey for the prevalence of Brucella-positive MAC and its associated factors.

METHODS

MAC samples (n=55), each one from a different rural family-based cheese-processing agroindustry, were analysed for Brucella by direct polymerase chain reaction (PCR) species-specific DNA detection and cultivation-based approaches.

RESULTS

Among 55 MACs that were analysed, we found 17 Brucella DNA-positive samples (30.9% [95% confidence interval {CI} 18.7 to 43.1]) by PCR and, for the first time, from one MAC (1.8% [95% CI 0.5 to 9.7]), viable Brucella abortus was recovered by cultivation. Higher values for two variables, the number of lactating cows per herd (p=0.043) and daily milk production per herd (p=0.043), were each associated with Brucella-positive MAC, which concentrated in three high-risk and one low-risk spatial clusters.

CONCLUSIONS

MAC may be a source of Brucella for humans, since the positive samples were from batches that were sold by cheesemakers. This should be of concern and encourage cooperation between the health and agriculture sectors in order to mitigate this public health risk through One Health integrated approaches.

Research Note: Antimicrobial resistance profile of Enterococcus spp. isolated from the eggshell of laying hens submitted to pharmacological treatment

The occurrence of antimicrobial resistance in microorganisms isolated from eggshells, especially Enterococcus, might serve as a parameter to assess the selection of bacteria due to the use of drugs in the diet of laying hens. In order to evaluate the frequency and the antimicrobial resistance profile of Enterococcus spp. isolated from the eggshells, 225 Hy-line laying hens were submitted to a 25-d long trial. The treatments were the following: hens fed ration without antimicrobials (control) and groups that received oxytetracycline (10 mg kg⁻¹), doxycycline (20 mg kg⁻¹), lincomycin (50 mg kg⁻¹), and enrofloxacin (10 mg kg⁻¹) in the ration for 5 d. Six replications were analyzed per treatment, composed of a pool of 5 eggs each. They were collected before treatment and on days 3, 6, 15, and 25, totaling 150 samples. Eggshells were submitted to counts of Enterococcus spp., which were identified by proteomic analyses. Antimicrobial resistance was determined by the disk-diffusion test. It was observed that 97.3% (n = 146) of the samples were contaminated with Enterococcus spp. There were no differences (P > 0.05) in the bacterial counts between treatments on the same day of evaluation. E. faecalis and E. faecium were the most frequent on the eggshells of all treatments. Multiresistance to the four classes of antimicrobials was also verified in the isolated bacteria. A total of 83% of the Enterococcus isolates showed resistance to neomycin, which was not administered to the hens, demonstrating an environmental problem. Thus, feeding laying hens with diets added with antimicrobials induces drug resistance in Enterococcus spp., isolated form the eggshells.

Effects of packaging, mineral oil coating, and storage time on biogenic amine levels and internal quality of eggs

This study was carried out with the aim of evaluating the effects of mineral oil application on eggshells and the use of plastic packages with lids on the physical-chemical and microbiological quality and biogenic amine contents of eggs stored under refrigeration for up to 125 d. A total of 1,920 eggs from 46-wk-old Hyline W36 laying hens were randomly distributed into 4 groups soon after classification: (i) 480 eggs were stored in pulp carton tray packages; (ii) 480 eggs were stored in plastic packages with lids; (iii) 480 eggs were stored in carton packages after the application of mineral oil; and (iv) 480 eggs were stored in plastic packages with lids after the application of mineral oil. The internal quality was measured by Haugh units, by the counts of mesophilic and psychrotrophic microorganisms, by the most probable number of total and thermal-tolerant coliforms, by the counts of molds and yeasts, by the analysis of Salmonella spp. and Staphylococcus spp., and by the levels of biogenic amines in the egg yolk and albumen. The application of mineral oil to the eggshell resulted in higher Haugh unit values throughout storage, and the use of plastic packages altered the internal quality. The application of mineral oil and the use of packaging had no effects on the microbiological and biogenic amine results. Microbiological analyses showed the absence of Salmonella spp., Staphylococcus aureus, thermal-tolerant coliforms, and fungi. However, the highest counts of mesophilic (1.1 × 10(7) cfu/g) and psychrotrophic (6.7 × 10(7) cfu/g) microorganisms were recorded. The highest values of biogenic amines detected and quantified were putrescine (2.38 mg/kg) and cadaverine (7.27 mg/kg) in the egg yolk and putrescine (1.95 mg/kg), cadaverine (2.83 mg/kg), and phenylethylamine (2.57 mg/kg) in the albumen. Despite these results, the biogenic amine levels recorded were considered low and would not be harmful to consumer health.