Safety of frozen liver for human consumption

Abstract

The objective of this study was to ensure and evaluate the safety of imported frozen beef liver traded in supermarkets of Kafr El-Sheikh Governorate, Egypt, through detection of Salmonella typhimurium, Salmonella enteritidies, Escherichia coli O157:H7, antibiotic residues, and aflatoxin B1 residue. Fifty samples of imported frozen liver were randomly collected from different shops at Kafr El-Sheikh Governorate for isolation of S. typhimurium, S. enteritidies, and E. coli O157:H7. The results revealed that for both microorganisms 4% of the examined samples presumed to contain Salmonella and E. coli O157:H7 organisms, according to the colonial character on Harlequin Salmonella ABC agar media and Harlequin SMAC-BCIG agar media. According to biochemical and serological identifications, both organisms could not be detected in the examined samples. A total of 29 (58%) samples were positive for antibiotic residues, using the Premi test (a broad-spectrum screening test for the detection of antibiotic residues in meat) at or below the maximum residue limits. In addition, aflatoxin B1 was detected in one (2%) samples with a concentration of 1.1 μg/kg. The results reflect that there was good hygiene practice for handling and preparation of frozen liver while selling to consumers. However, a high percentage of antibiotic residues reflect ignorance of withdrawal time before slaughtering of animals as well as misuse of antibiotics in veterinary fields. Furthermore, aflatoxin B1 residue was detected in examined frozen liver samples at a concentration below the maximum residual level, which is not enough to cause threat to humans, but it is enough to cause problem if it is eaten regularly reflect contamination of animal feed with aflatoxins.

Keywords: E. coli O157:H7; Salmonella; aflatoxin B; antibiotic; liver.

Figure 1

Standard curve of AFB1 (R² = 0.9937). AFB1 = aflatoxin B1.