Exploring the microbiological quality and safety of dry-aged beef: A cross-sectional study of loin surfaces during ripening and dry-aged beef steaks from commercial meat companies in Belgium.

A cross-sectional survey was undertaken in Belgian beef producing companies to study the current practices and the microbiological load of dry-aged loins (during production) and trimmed steaks (final product). In each company, the temperature and relative humidity of the ripening chamber were measured, and two loins (each in a different stage of the ripening process) were sampled. From the surface of each loin, a lean meat and adipose tissue sample was analysed separately, and different groups of bacteria, yeasts and moulds were enumerated. The average relative humidity in the ripening chambers was 72 ± 13% and the temperature ranged between 0.0 °C and 5.9 °C. During the drying process, most of the lean meat and adipose tissue samples showed high numbers of total psychrotrophic aerobic bacteria, Pseudomonas spp., psychrotrophic lactic acid bacteria, and yeasts, but the variation between loins was high. The microbiological load on freshly cut dry-aged steaks was generally lower than on loin surfaces, but both psychrotrophic aerobic and anaerobic bacteria were present inside several steaks. The water activity inside dry-aged beef steaks was high (aw ≥ 0.98), which could allow growth of psychrotrophic pathogens, though more in-depth studies are necessary to determine potential growth during the storage of (trimmed) steaks or even inside loins during the dry-aging process.

Occurrence and Antibiotic Susceptibility of Listeria Species and Staphylococcus aureus in Cattle Slaughterhouses of Kerala, South India.

A total of 765 samples were collected from beef carcasses, knives, cutting table surfaces, beef, hands, air, and water from four cattle slaughterhouses of Kerala, South India, to determine the occurrence and antibiotic susceptibility of Listeria species and Staphylococcus aureus. Listeria spp. were isolated from beef carcasses (2.0%), knives (3.7%), cutting table surfaces (1.9%), beef (0.7%), and water (1.3%). The identified species were Listeria monocytogenes (0.1%), Listeria innocua (0.9%), and Listeria ivanovii (0.4%). Most of the Listeria spp. were susceptible to majority of the antibiotics tested. The virulence genes were not detected in Listeria spp. However, all the L. innocua isolates were found to harbor the iap gene. The overall occurrence of S. aureus in slaughterhouses was 50.8%. The highest occurrence was observed on hands of abattoir workers (79.6%) and beef carcasses (59.9%). The isolates were commonly resistant to penicillin (38.0%), followed by ceftriaxone (31.9%), ampicillin (29.0%), amoxicillin (28.8%), tetracycline (24.4%), and chloramphenicol (23.9%). Overall, 53.0% of S. aureus isolates were resistant to three or more antibiotics. Vancomycin and methicillin resistance were observed in 8.5% and 5.4% of S. aureus isolates, respectively. Eight methicillin-resistant S. aureus isolates were found to harbor the mecA gene. In conclusion, Listeria spp. was only rarely found in the slaughterhouse environment and on beef. Nevertheless, the recovery of L. monocytogenes from a water reservoir containing sea water that was used to wash carcasses indicates the potential risk of contamination of the carcasses with L. monocytogenes when using sea water. S. aureus was frequently isolated from abattoir workers and beef carcasses, and the occurrence of S. aureus differed significantly between slaughterhouses. The high occurrence of S. aureus, which were often resistant toward different antibiotics, represents a significant public health concern.

Isolation and Seroprevalence of Aeromonas spp. Among Common Food Animals Slaughtered in Nagpur, Central India.

Aeromonads are ubiquitous foodborne pathogens with a global distribution. Animal-origin foods and contaminated animals are the main sources of Aeromonas infection to humans. So far little is known about the occurrence of Aeromonas spp. in food-producing animals in India. The present study was conducted to determine the prevalence and seroprevalence of Aeromonas species from 50 each of meat, blood, and sera samples collected from cattle, buffaloes, goats, and pigs slaughtered in and around Nagpur, Central India. Alkaline peptone water and ampicillin dextrin agar were used to isolate Aeromonas spp. An indirect enzyme-linked immunosorbent assay (ELISA) was standardized by use of whole-cell antigen (WC) and outer membrane protein (OMP) of Aeromonas hydrophila (MTCC 646). Aeromonads were isolated from 44 (22%) of the meat samples, and 1 (0.5%) from the blood samples. Seroprevalence by indirect ELISA-based WC antigen was estimated as 68% in cattle, 44% in buffaloes, 60% in goats, and 30% in pigs. OMP-based ELISA yielded a seroprevalence of 56%, 48%, 52%, and 22% in cattle, buffaloes, goats, and pigs, respectively. The results revealed that OMP-based ELISA and WC-based ELISA were in agreement with one another. Isolation along with high seropositivity demonstrates the presence of foodborne Aeromonas spp. in the Nagpur city of Central India.