Antibacterial activity of pepsin-digested lactoferrin on foodborne pathogens in buffered broth systems and ultra-high temperature milk with EDTA.
OBJECTIVE
To evaluate the antimicrobial activity in peptone yeast extract glucose (PYG) broth and ultra-high temperature (UHT) milk of bovine lactoferrin hydrolysate (LFH) with pepsin against the foodborne pathogens Salmonella Stanley, Escherichia coli, Listeria monocytogenes and Staphylococcus aureus.


RESULTS
The LFH was suspended in PYG and the minimum inhibitory concentration for each pathogen determined. The LFH was also suspended in UHT milk adjusted to pH 4 or 7, samples incubated at 4 or 35 degrees C and the change in bacterial cell population determined. Experiments in UHT milk were conducted using L. monocytogenes and E. coli O157:H7. At pH 4 LFH reduced the population of E. coli O157:H7 and L. monocytogenes by approx. 2 log; however, only E. coli O157:H7 was inhibited in samples adjusted to pH 7. The addition of EDTA (10 mg ml(-1)) to UHT milk supplemented with LFH did not markedly influence the growth of E. coli O157:H7 or L. monocytogenes.


CONCLUSIONS
The results suggest that, under low pH and refrigeration conditions, LFH can limit the growth or reduce the population of pathogenic bacteria in a dairy product.


CONCLUSIONS
Natural preservatives that are active against Gram-negative and Gram-positive bacteria are desirable to the food industry. This study demonstrates that LFH is effective in a complex food system. Moreover, the LFH used was not purified, making its use by industry more attractive.
Murdock
C A
CA
Department of Food Science, Rutgers University, New Brunswick, NJ 08901-8520, USA.
Matthews
K R
KR
D000818:Animals; D001419:Bacteria / Q000187:drug effects*; D002417:Cattle; D003470:Culture Media; D004492:Edetic Acid; D004926:Escherichia coli / Q000187:drug effects; D005516:Food Microbiology; D005947:Glucose / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007781:Lactoferrin / Q000378:metabolism* / Q000494:pharmacology*; D008089:Listeria monocytogenes / Q000187:drug effects; D008892:Milk; D010434:Pepsin A / Q000378:metabolism*; D010461:Peptones / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D011492:Protein Hydrolysates / Q000378:metabolism; D012475:Salmonella / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects
D003470:Culture Media; D010461:Peptones; D011492:Protein Hydrolysates; D004492:Edetic Acid; D007781:Lactoferrin; D010434:Pepsin A; D005947:Glucose