Food safety assessment of burger patties with added herbal plant material

Abstract

Burger patties containing Wild Garlic (WG) leaves or Wild Garlic extracts (WGE) were analyzed to determine possible bacterial contamination origination from the plant material. Microbiological analysis of the bacterial load was performed using nine standard ISO methods. In the WG and WGE samples, the presence of Salmonella spp., Listeria monocytogenes, and Shiga toxin-producing Escherichia coli (STEC) was not confirmed. The number of Escherichia coli (β-glucuronidase positive), Enterobacteriaceae, coagulase-positive staphylococci, and Bacillus cereus was < 10 CFU/g. The total bacteria count in the WG sample was within tolerance values (0.04 × 10**5 CFU/g), but in the WGE, it exceeded the limits set by the WHO (1.10 × 10**5 CFU/g vs. > 10**5). Using the BD BBLCRISTAL Gram-Positive (GP) Identification (ID) system, we identified Staphylococcus epidermidis, Bacillus pumilus, and Staphylococcus aureus. A particular danger lies in the detected presence of the potential enterotoxigenic and antibiotic-resistant strains of Staphylococcus aureus, which was not coagulase positive. The samples of control and fortified BU with WGE were tested on days 0, 5, and 10 during cold storage and 90 days after freezing. By comparing the contamination levels on days 5 and 10, mass contamination was observed in the samples of the modified BU. On day 10, the contamination level was higher compared to day 5. The microbiological load was highest in samples from PB II on both days. The bacterial load of the frozen BU samples was significantly lower after 90 days than during cooling but was still higher than in WGE-fortified BU compared to the control (fully correlated with the amount of WGE added).