Antimicrobial Activity of Lactiguard® against Foodborne Pathogens in Laboratory Media

Introduction: Foodborne pathogens, including Salmonella and Listeria, give rise to severe issues in food industry by causing a substantial health risk to consumers. Lactiguard^®is particularly good at reducing pathogenic risks because this product reportedly has very strong antimicrobial properties.

Purpose: The objective of this study was to evaluate the effect of dose and temperature on the inhibition activity of the GRAS bacterial anti-microbial preparation against Salmonella and Listeria in laboratory media.

Methods: The cocktail of NP51+NP3+NP7+NP28 was individually added at 1x10⁷, 1x10⁸ and 1x10⁹ CFU/ml into TSB broth containing Salmonella or Listeria (Ca. 1x10⁴CFU/ml). Then, these samples were incubated under anaerobic conditions at 37 and 4 °C, respectively. Pathogen enumeration was evaluated at hours 0, 2, 4, 8, 12, 24 and 48 at 37 °C, and on days 0, 1, 2, 3, 5 and 7 at 4°C. 

Results: Our results indicated that at 37°C, 1x10⁸ and 1x10⁹ CFU/ml of the preparation have led to a significant (P < 0.05) reduction in Salmonella since hour 4, while a significant (P < 0.05) reduction in Listeria with 1x10⁹ of the preparation was observed since hour 2. And, 1 x 10⁸ CFU/ml of the preparation led to a significant (P < 0.05) reduction in Listeria only from hour 8 to 24; however, at 4°C, a significant (P < 0.05) reduction in Salmonella was observed only with 1x10⁷ CFU/ml of the cocktail on days 2 and 3. For Listeria, 1x10⁸ and 1x10⁹ CFU/ml of the cocktail have led to a significant (P < 0.05) reduction since days 2 and 1, respectively, and 1x10⁷ CFU/ml of the cocktail only attributed to a significant (P < 0.05) reduction on day 7.

Significance: The use of Lactiguard^® is a very effective intervention to control Salmonella and Listeria in laboratory media and its inhibition activity in food products must continue to be tested.