Impact of display and handling on the chemical and microbial content of beef frozen liver

الملخص EN

A total of 60 beef frozen liver samples from different market retail from different origins in Kafr-El-sheikh Governorate were collected then transferred immediately to the laboratory under aseptic conditions.

These collected samples were subjected to chemical, bacteriological and mycological analysis.

The obtained results revealed that the mean values of pH and TVN-B (Total Volatile Nitrogen) in examined frozen liver samples were 5.54±0.01 and 6.99±0.28 mg/100gm, respectively.

While in microbial analysis the Staphylococcus aureus was isolated from 44 samples (66.7%), and there were two strains have the ability to produce enterotoxins (A), only one strain can produce enterotoxine (B), one strain can produce enterotoxine (B&D) and one strain produce enterotoxine (A&D).

The percentage of other Staphylococci were Staph saprophyticus (12.5%), Staph epidermidis (23.8%), Staph intermedius (7.5%) and Staph capitis (2.5%).

Also the mold were isolated from 80% from the examined frozen liver samples and the isolated mold strains were identified as 24 A.niger (26.1%) , 10 A.

flavus (10.9%), 8 A.

fumigatus (8.7%), 10 Penicillium (10.9%), 6 Fusarium Spp.

(6.5%), 6 Rhizopus Spp.

(6.5%), 6 Mucor Spp.

(6.5% ), 6 Thamnidium Spp.

(6.5%), 4 Nigrospora Spp.(4.3%) and 2 Trichothecium Spp.

(2.2%).

Multiplex PCR was done to detect the virulence of isolated strains of A.flavus and found that the Lane(1) was Positive A.

flavus strain for nor-1 and omtA genes, Lane(2) was Positive A.

flavus strain for nor-1, ver-1, omtA and aflR genes, Lane(3) was Positive A.

flavus strain for nor-1 gene, Lane(4) was Positive A.

flavus strain for nor-1, ver-1 and aflR genes and Lane(5) was Positive A.

flavus strain for nor-1, ver-1 and omtA genes.

In conclusion, the obtained results indicate that consumption of frozen liver may cause a public health hazard to the consumer.

Measures to control the quality of beef frozen liver during display and handling should be taken.