Antilisterial Bacteriocin-producing Strain of Lactobacillus curvatus CWBI-B28 as a Preservative Culture in Bacon Meat and Influence of Fat and Nitrites on Bacteriocins Production and Activity

Abstract

The objectives of this study were to evaluate the effectiveness of a bacteriocin-producing Lactobacillus curvatus CWBI-B28 to inhibit the growth of Listeria monocytogenes in de Man, Rogosa and Sharp (MRS) broth and in bacon meat. A co-culture of L. monocytogenes with the Bac strain in MRS broth, resulted in a reduction of the pathogen counts by 4.2 log cycles after 24h of incubation at 37°C. In bacon, the counts of L. monocytogenes was reduced to below the detectable limit (<10cfu/g) in samples inoculated with the Bac strain within 1 or 2 weeks in absence or presence of nitrites (210mg/kg), respectively. However, a week later, a re-growth of the pathogen has occurred. In contrast, no such reduction in Listeria cfus was observed in samples treated with the Bac derivative of Lb. curvatusCWBI-B28. Nonetheless, the extent of inhibitory effect of the Bac strain against L. monocytogenes in bacon was somewhat reduced in the presence of nitrites. A separate study on the influence of nitrites and fats on growth and bacteriocin production by Lb. curvatus CWBI-B28 revealed that the curing agent affects the growth of the Bac strain and, thereby bacteriocin production and activity only at concentrations (>5%) far beyond those allowed in the meat industry. Fat content did not affect the bacterial growth even at the highest concentration used (i.e. 50%), however, it interfered significantly with the detection of AUs and the antilisterial activity. Use of the Bac Lb. curvatus CWBI-B28 has proven efficient in controlling L. monocytogenes in bacon despite the slight antagonistic effect of nitrites, however the efficacy was dramatically reduced upon extended period of storage at 4°C.

Antimicrobial peptides generated from milk proteins: a survey and prospects for application in the food industry. A review

“…Another potential advantage of the preservation strategy using proteolytic LAB is the possibility to use specific bacteriocin‐producing strains of LAB which are also able to generate antimicrobial peptides from food proteins. In this regard, a strain of Lactobacillus curvatus has been shown to produce two distinct bacteriocins and to generate an antimicrobial peptide from the tryptic digest of β‐casein present in de Man, Rogosa and Sharp (MRS) broth (Ghalfi et al 2010), and the effectiveness of this Lactobacillus strain in food preservation has been demonstrated (Ghalfi et al. 2006a,b, 2007).…”

Isolation and Characterization of an Anti-listerial Bacteriocin from Leuconostoc lactis SD501

“…In addition, the combination of a cell-bound bacteriocin produced by Lb. curvatus CWBI-B28 with savory essential oils or oregano effectively reduced the number of viable L. monocytogenes in pork meat ( Ghalfi et al., 2006 ).…”

Biopreservation of Meats and Meat Products

“…Inoculation of strains producing sakacin P or leucocin in cooked meat products was shown to inhibit growth of listeria (Katla et al 2002 ;Jacobsen et al 2003 ), and protective L. sakei cultures were also shown to inhibit L. monocytogenes and E. coli O157:H7 in vacuum-packed cooked meat products (Bredholt et al 1999 ). The bacteriocinogenic strain L. curvatus CWBI-B28 reduced L. monocytogenes levels below detection limits in bacon meat within 1 or 2 weeks in absence or presence of nitrites, respectively (Ghalfi et al 2006 ). Anti-listerial effect was also observed with a plantaricin producing L. plantarum strain in cooked chicken meat (Enan 2006 ).…”