Antimicrobial Effect of Malpighia Punicifolia and Extension of Water Buffalo Steak Shelf‐Life

Abstract

In the present study, a multiple approach was used to characterize Malpighia punicifolia extract and to evaluate its inhibitory activity against several meat spoilage bacteria. First, volatile fraction, vitamins and phenolic compounds of the extract obtained by supercritical fluid extraction were determined by GC‐MS and HPLC. Then, the antimicrobial action of the extract was in vitro evaluated against Pseudomonas putida DSMZ 291T, Pseudomonas fluorescens DSMZ 50009T, Pseudomonas fragi DSMZ 3456T, and Brochothrix thermosphacta DSMZ 20171T by the agar well diffusion assay and by the agar dilution test. Based on the results of the minimum inhibitory concentration (MIC) against the assayed bacteria, 4 different concentrations of the extract were used in a challenge test on water buffalo steaks stored for 21 d at 4 °C. Results of chemical analyses showed that M. punicifolia extract is characterized by the presence of several compounds, already described for their antimicrobial (phenolic acids, flavonones, and furanes) and antioxidant (ascorbic acid) properties. The in vitro detection of antimicrobial activities highlighted that the extract, used at 8% concentration, was able to inhibit all the target bacteria. Moreover, very low MIC values (up to 0.025%) were detected. In situ tests, performed on water buffalo steaks treated with the extract in the concentration range 0.025% to 0.05%, showed a strong inhibition of both intentionally inoculated bacteria and naturally occurring microorganisms. Positive results, in terms of color and odor, were also observed during the entire storage of steaks preserved with the extract.

Preliminary Evaluation of the Safety and Probiotic Potential of Akkermansia muciniphila DSM 22959 in Comparison with Lactobacillus rhamnosus GG

“…The antimicrobial activity of the strains was conducted according to the agar well diffusion assay described by Tremonte et al [29] with same modifications. Briefly, 20 mL of BHI soft agar (0.7% agar) inoculated with an overnight culture of each indicator strain (final concentration of about 7 Log CFU/mL) were poured in Petri plates.…”

“…Studies on the microbial cell surface have shown that the presence of (glycol-) proteinaceous material results in higher hydrophobicity, whereas hydrophilic surfaces are associated with the presence of polysaccharides [24,29]. Hydrophobic cell surfaces were demonstrated to be highly adherent-more than 40%-to apolar solvents [24,43].…”

Detection of Antilisterial Activity of 3-Phenyllactic Acid Using Listeria innocua as a Model

“…In the last years, several bio-control strategies have been developed to improve the safety and to extend the shelf-life of various foods. In this field, protective microbial cultures ( Sorrentino et al, 2013 ; Tremonte et al, 2017a ) and treatments with natural substances ( Reale et al, 2011 ; Tipaldi et al, 2011 ; Catalano et al, 2015 ; Tremonte et al, 2016a ) showed positive effects. The use of natural compounds, in particular antimicrobials produced by protective cultures, may represent an important tool in the food biopreservation, also considering the consumer demand for safe and healthy foods, in terms of reduction in chemical additives and provision of beneficial effects ( Reale et al, 2011 ; Succi et al, 2014 ).…”

Homology-Based Modeling of Universal Stress Protein from Listeria innocua Up-Regulated under Acid Stress Conditions

“…Similarly to L. innocua , pathogenic L. monocytogenes is frequently found in various foodstuffs (Kovacevic et al, 2012; Jami et al, 2014; Ebner et al, 2015; Melo et al, 2015), especially those characterized by pH values higher than 4.4 (CAC, 2009). In the food industry a number of strategies are used to inhibit the growth of undesirable microorganisms, like technological processing (Tremonte et al, 2014), addition of natural substances (Tipaldi et al, 2011; Tremonte et al, 2016), protective microbial cultures (Sorrentino et al, 2013) as well as organic acids (Davidson et al, 2013). Unfortunately, in the case of several food types, sub-lethal pH values may induce resistance mechanisms to acid stress, which make the cells more resistant to severe acid conditions (Gandhi and Chikindas, 2007).…”