Oxoid claims method is speedy way of recording E. coli

UK-based Oxoid, part of the Thermo Fisher Scientific group, said it has increased the efficiency of its Brilliance​ E. coli/coliform Selective Agar to enumerate E. coli​ and other coliforms from food and water samples at a faster rate.

Pathogens such as E. coli​ and Salmonella​ form part of the Enterobacteriaceae family, the enumeration of which is a key hygiene parameter in EU regulation on microbiological criteria for food.

Enumeration methods determine the amount of groups of bacteria. Such quality indicators allow industries to determine their level of process contamination.

According to Oxoid, the Brilliance​ method has been optimised to allow purple, presumptive-positive E. coli​ colonies to be confirmed directly on the plate through the performance of the indole reaction, without the addition of any further steps.

The diagnostics firm explained that the chromogenic agents within the medium are used to detect the ß-glucuronidase activity of E. coli​ and the ß–galactosidase activity of coliforms (including E. coli​), allowing them to be clearly differentiated on the culture plate.

“When the plate is flooded with Kovacs solution E. coli​ colonies turn a distinctive cherry red colour, allowing rapid and easy enumeration of confirmed E. coli​ colonies,”​ said the company.

E. coli in beef​

Meanwhile, a new study purports that the addition of cranberry concentrate to ground beef may serve as a supplementary hurdle to control potential E. coli​ O157:H7 outbreaks associated with ground beef.

Researchers at the University of Maine examined the potential for cranberry concentrate (CC) to be used as a natural food preservative by examining its antimicrobial effect on the growth of Escherichia coli O157:H7​ inoculated in ground beef as well as its organoleptical effect on beef burgers.

The findings of the research, which was published in the journal Food Microbiology, ​indicated that cranberry concentrate at the tested concentrations did not cause significant negative impact on the flavour, taste or colour of burgers and also possessed antimicrobial effects.

In the US this year, millions of pounds of raw ground beef were recalled because of E. coli​ O157:H7 contamination, and the researchers stress that effective methods to prevent and eliminate such contaminations in ground beef are as such essential for the food industry and consumers.