Inhibition ofBacillus licheniformisspore growth in milk by nisin, monolaurin, and pH combinations

Abstract

M . M AN S OU R, D . A MR I , A . B O UT TE F RO Y, M . L IN D ER AN D J. B. M IL LI E RE . 1999. The effects of nisin and monolaurin, alone and in combination, were investigated on Bacillus licheniformis spores in milk at 37°C. In the absence of inhibitors, germinated spores developed into growing vegetative cells and started sporulation at the end of the exponential phase. In the presence of nisin (25 IU ml −1 ), spore outgrowth was inhibited (4 log 10 reduction at 10 h). Regrowth appeared between 10 and 24 h and reached a high population level (1·25 × 10 8 cfu ml −1 ) after 7 d. Monolaurin (250 mg ml) had a bacteriostatic effect during the first 10 h but thereafter, regrowth occurred slowly with a population level after 7 d (4 × 10 5 cfu ml) lower than that of nisin. Different combined effects of nisin (between 0 and 42 IU ml ) were investigated using a Doehlert matrix in order to study the main effects of these factors and the different interactions. Results were analysed using the Response Surface Methodology (RSM) and indicated that nisin and monolaurin had no action on spores before germination; only pH values had a significant effect (P ¾ 0·001), i.e. spore count decreased as the pH value increased in relation to germination. Sublethal concentrations of nisin (30 IU ml ) and monolaurin (100 mg ml −1 ) in combination acted synergistically on outgrown spores and vegetative cells, showing total inhibition at pH 6·0, without regrowth, within 7 d at 37°C.

Comparison of antibacterial effect of seven 1-monoglycerides on food-borne pathogens or spoilage bacteria

“…In this case, MAG-C12:0 can inhibit not only the growth of Bacillus spp. but also the production and germination of spores (Mansour et al 1999;Mansour and Millière 2001). In our case, the most resistant gram-positive bacterium to the effect of MAG-C12:0 was Staph.…”

“…Under certain conditions, fatty acids and monoglycerides can inhibit the growth of vegetative forms of pathogenic bacteria, viruses (Thormar and Hilmarsson 2007), spore-forming bacteria (Mansour et al 1999;Skrivanova et al 2006) or yeasts (Bergsson et al 2001). However, food composition can influence the inhibitory effect of both monoglycerides and fatty acids.…”

The nisin improves broiler chicken growth performance and interacts with salinomycin in terms of gastrointestinal tract microbiota composition

“…and various substances were repeatedly observed. Combinations of ethanol (Brewer et al, 2002), monolaurin (Mansour et al, 1999), sucrose fatty acid esters -sucrose palmitate and sucrose stearate (Thomas et al, 1998) and reuterin (Arqués et al, 2004) with nisin reduced L. monocytogenes, B. licheniformis (vegetative cells and spores), B. cereus (cells and spores), L. plantarum and Staphylococcus aureus development, respectively. Supplementation of these complexes did not exert a negative effect on Gram-negative pathogens.…”

Inhibition of Bacillus anthracis Spore Outgrowth by Nisin

“…To date, nisin inhibition of Bacillus spore outgrowth has been documented by various methods, including the spectrophotometric measurement of liquid culture turbidity (3), the enumeration of CFU (4,14,32,35,43), well diffusion assays on solid agar (14,39), and microscopic observations (41). Although these approaches are useful, they have provided few details about nisin's mode of action against Bacillus spores.…”