Sodium lactate, sodium diacetate and pediocin: Effects and interactions on the thermal inactivation of Listeria monocytogenes on bologna

Antibacterial Activity of Pediocin and Pediocin-Producing Bacteria Against Listeria monocytogenes in Meat Products

One of the most important challenges in the food industry is to produce healthy and safe food products, and this could be achieved through various processes as well as the use of different additives, especially chemical preservatives. However, consumer awareness and concern about chemical preservatives have led researchers to focus on the use of natural antimicrobial compounds such as bacteriocins. Pediocins, which belong to subclass IIa of bacteriocin characterized as small unmodified peptides with a low molecular weight (2.7-17 kDa), are produced by some of the Pediococcus bacteria. Pediocin and pediocin-like bacteriocins exert a broad spectrum of antimicrobial activity against Gram-positive bacteria, especially against pathogenic bacteria, such as Listeria monocytogenes through formation of pores in the cytoplasmic membrane and cell membrane dysfunction. Pediocins are sensitive to most protease enzymes such as papain, pepsin, and trypsin; however, they keep their antimicrobial activity during heat treatment, at low temperatures even at -80°C, and after treatment with lipase, lysozyme, phospholipase C, DNase, or RNase. Due to the anti-listeria activity of pediocin on the one hand and the potential health hazards associated with consumption of meat products on the other hand, this review aimed to investigate the possible application of pediocin in preservation of meat and meat products against L. monocytogenes.

Optimization of the In Vitro Bactericidal Effect of a Mixture of Chlorine and Sodium Gallate against Campylobacter spp. and Arcobacter butzleri

ABSTRACT

Campylobacter spp. and Arcobacter butzleri are foodborne pathogens associated with the consumption of contaminated raw chicken meat. At the industry level, the combination of new and common antimicrobials could be used as a strategy to control the presence of pathogens in chicken carcasses. The objective of this study was to determine the bacteriostatic and bactericidal effects of a mixture of chlorine (Cl) and sodium gallate (SG) on a mixture of two Campylobacter species (Campylobacter jejuni and Campylobacter coli) and A. butzleri. Using a central composite experimental design, it was established that the optimum inhibitory SG-Cl concentration for Campylobacter spp. was 44 to 45 ppm. After 15 h of incubation, Campylobacter species growth was reduced by 37.5% and the effect of Cl was potentiated by SG at concentrations above 45 ppm. In the case of A. butzleri, optimum levels of 28 and 41 ppm were observed for SG and Cl, respectively; no synergism was reported, as this bacterium was more sensitive to lower Cl concentrations than Campylobacter. After a 20-min pretreatment with peracetic acid (50 ppm), the optimum condition to achieve a >1.0-Log CFU/mL reduction of Campylobacter spp. was exposure to 177 ppm of Cl and 44 ppm of SG for 56 min. As A. butzleri showed lower resistance to the bacteriostatic effect of the Cl-SG combination, it was assumed that optimum bactericidal conditions for Campylobacter spp. were effective to control the former; this was confirmed with subsequent validation of the model. The SG-Cl combination has bactericidal properties against Campylobacter and A. butzleri, and it may be a useful strategy to improve sanitary practices applied in the poultry industry.

HIGHLIGHTS

Effect of dietary sodium diacetate on growth performance, carcass characteristics, meat quality, intestinal pH and Escherichia coli of broilers

This research report investigated the influences of diet supplemented with sodium diacetate (SD) on growth performance, carcass characteristics, meat quality, and intestinal pH and Escherichia coli count of broilers. A total of 240 1-day-old Arbor Acres chicks were randomly allocated into four groups fed with basal diets containing 0% (Control group), 0.01%, 0.03%, and 0.05% SD. At 42 days of age, the final weight, bodyweight gain, pre-evisceration weight, eviscerated weight, and breast muscle weight were increased in the 0.05% SD group compared with the Control group (P < 0.05). The 0.05% SD group also showed an increased water-holding capacity in the breast and thigh meat (P < 0.05). However, this group also showed a decrease in the lightness value of thigh meat (P < 0.05). There was a tendency towards a decrease in pH values of duodenum, jejunum, ileum, and appendix with the increase in SD supplementation (0.01–0.05%). Broilers in the 0.05% SD group had a lower pH in the jejunum than those in the Control group (P < 0.05). SD supplementation in diets decreased the E. coli count in the small and large intestines (P < 0.05). This study suggests that SD supplementation in diets provides a nutritional strategy to improve growth performance, carcass characteristics, meat quality, and intestinal health of broilers.