Microbiological quality and growth potential of ethnic ready-to-eat and ready-to-heat foods from three selected European cities.
Abstract
This study assessed the microbiological quality and safety of ethnic ready-to-eat (RTE) and ready-to-heat (RTH) foods obtained from retail and take-away settings in three European cities: Burgos, Spain; Ghent, Belgium; and Vienna, Austria. A total of 99 samples (94 retail and 5 take-away) were analysed for hygiene indicators, including mesophilic aerobic colony counts, Enterobacteriaceae, β-glucuronidase-positive Escherichia coli, and Listeria spp., as well as for foodborne pathogens, including Listeria monocytogenes, presumptive Bacillus cereus, and Salmonella spp. Key physicochemical parameters related to microbial growth, namely pH and water activity (aw), were also determined. Aerobic colony counts ranged from 1.9 to 10.0 log CFU/g. Enterobacteriaceae counts ≥1.0 log CFU/g were observed in 20/99 samples (20.2%), while 79/99 samples (79.8%) showed counts <1.0 log CFU/g. β-glucuronidase-positive E. coli was detected in 4/99 samples (4.0%), suggesting limited faecal contamination. Presumptive Bacillus cereus counts ≥2.0 log CFU/g were observed in 11/99 samples (11.1%), with only one sample exceeding 5.0 log CFU/g. Listeria spp. counts ≥1.0 log CFU/g were observed in 11/99 samples (11.1%). Listeria monocytogenes was detected in 2/99 samples (2.0%), both corresponding to gyoza products with high concentrations (>6.0 log CFU/g). Salmonella spp. was detected in one hummus sample (1.0%). Physicochemical analysis showed that most products with available pH and aw data (84/96; 87.5%) were located within the permissive region of the NACMCF pH-aw framework, indicating an intrinsic potential to support microbial growth. Overall, although most samples showed satisfactory microbiological quality, the detection of high pathogen levels in a small number of samples highlights that ethnic RTE and RTH foods may pose a potential risk when contamination occurs. These findings underline the need for continued monitoring and appropriate hygiene and temperature control measures.