The SO2-extract combinations inhibited microbial growth, increasing shelf life by three days, although trends indicated only marginal improvement in microbial quality as a result of the addition of ascorbate, GTE and GSE.
The shelf life of raw meat is usually limited by microbial spoilage. Raw patties have a shelf life of around 7 days in refrigeration and aerobiosis, depending on hygiene and preservation conditions.
SO2 is very active against gram negative bacteria, such as Enterobacteriaceae.
Reducing agents such as ascorbate or polyphenols could protect SO2 against oxidation, enabling SO2 to act for more time.
Some authors have suggested that tea and grape polyphenols also have a certain antibacterial activity in vitro, although no specific studies on meat products have been made.
GSE would be mainly effective against gram positive bacteria, with gallic acid as the main active component.
GTE would inhibit E. coli, S. aureus, Staphylococcus epidermidis and Streptococcus mutans.
Currently used doses of ascorbate do not have an antimicrobial effect on psychrotrophics in raw patties