MICROBIAL ECOLOGY DYNAMICS DURING THE PROCESSING OF JERKED BEEF

Jerked beef (JB) is a salted, dried, and vacuum-packed meat product regarded as the commercial successor of charque, from which it differs mainly using curing salts (sodium nitrite/nitrate). As with charque, its preservation depends on the reduction of water activity (Aw) through salting, a condition that restricts overall microbial growth but does not prevent the survival of halotolerant pathogens such as Staphylococcus aureus and Listeria monocytogenes. In this context, mapping the cultivable microbiota across the manufacturing stages is an important tool to guide microbiological control and improve Hazard Analysis and Critical Control Point (HACCP) plans. This study aimed to identify and quantify the main microbial groups throughout the industrial processing of JB. Samples were collected in triplicate at the stages of raw material receiving, tenderization, injection (wet salting), dry salting, tumbling, washing, drying, stacked resting, and final product (n = 54), in an industry located in the state of São Paulo (SP), Brazil. Samples were analyzed for the presence of aerobic mesophilic, halotolerant, and halophilic bacteria, xerophilic molds, S. aureus, Escherichia coli, Salmonella spp., and L. monocytogenes, by plating on selective/differential media, with counts expressed as log CFU/g. Mesophilic bacteria showed counts ranging from 8.6 to 5.3 log CFU/g, with the greatest reduction observed during drying, while halotolerant and halophilic bacteria ranged from 8.3 to 5.0 and from <1 to 4.7 log CFU/g, respectively, reflecting progressive selection as salinity increased. Xerophilic molds reached 4.6 log CFU/g, concentrated mainly at the injection (wet salting) stage. Regarding pathogens, L. monocytogenes was detected in 8 of the 54 samples (14.8%), E. coli in 14 samples (25.9%), and S. aureus in only 1 sample (1.9%), while Salmonella spp. was not detected. These results indicate that, although the unit operations are effective in reducing the overall microbial load, the persistence of pathogens in a portion of the samples highlight stages that still require greater hygienic-sanitary control. It is concluded that JB, despite its intrinsic preservation conditions, presents points of pathogen contamination throughout processing, reinforcing the importance of continuous monitoring of the microbiota to ensure the microbiological safety and quality of the product.