Antimicrobial Effects of Corn Zein Films Impregnated with Nisin, Lauric Acid, and EDTA

Abstract

Bacterial growth during food transport and storage is a problem that may be addressed with packaging materials that release antimicrobials during food contact. In a series of five experiments, EDTA, lauric acid (LA), nisin, and combinations of the three antimicrobial agents were incorporated into a corn zein film and exposed to broth cultures of Listeria monocytogenes and Salmonella Enteritidis for 48 h (sampled at 2, 4, 8, 12, 24, and 48 h). Four experiments used starting cultures of 10(8) CFU/ml in separate experiments tested against each bacterium; the fifth experiment examined the inhibitory effect of selected antimicrobial agents on Salmonella Enteritidis with an initial inoculum of 10(4) CFU/ml. L. monocytogenes cell numbers decreased by greater than 4 logs after 48 h of exposure to films containing LA and nisin alone. No cells were detected for L. monocytogenes (8-log reduction) after 24-h exposure to any film combination that included LA. Of all film agent combinations tested, none had greater than a 1-log reduction of Salmonella Enteritidis when a 10(8)-CFU/ml broth culture was used. When a 10(4) CFU/ml of Salmonella Enteritidis initial inoculum was used, the films with EDTA and LA and EDTA, LA, and nisin were bacteriostatic. However, there was a 5-log increase in cells exposed to control within 24 h. The results demonstrate bacteriocidal and bacteriostatic activity of films containing antimicrobial agents.

Controlled Release Properties of Zein–Fatty Acid Blend Films for Multiple Bioactive Compounds

“…In contrast, blend film making with the potent antimicrobial fatty acid LAU gave films with the highest antimicrobial activity. This result was quite expected, since Hoffman et al 43 previously showed the high antimicrobial activity of LAUcontaining zein films against L. monocytogenes. Although the results of this work did not indicate antilisterial activity originated from OLE and LIN in zein films, the OLE and LIN solubilized properly in broth medium were reported to have a limited antimicrobial activity on L. monocytogenes.…”

Development of antimicrobial packaging materials for food preservation using bacteriocin from Lactobacillus casei

“…Their results showed that L. monocytogenes cell numbers decreased by greater than 4 logs after 48 h of exposure to films containing Lauric acid or nisin alone. 23 The study carried out by Cleveland and colleagues in 2001 have proved that bacteriocins are safe, natural antimicrobials and can be used for food preservation. 12 Mauriello and colleagues developed active polythene films antilisterial film by using the bacteriocin produced by L. curvatus.…”

Extração de zeína e sua aplicação na conservação dos alimentos

“…A adição de nisina e lisozima em filmes de zeína de milho ou proteína de soja auxiliaram no controle do desenvolvimento de Escherichia coli, Lactobacillus plantarum e Listeria monocytogenes em produtos cárneos (HOFFMAN et al, 2001). Os filmes contribuíram também para reduzir a oxidação lipídica e off-flavors em embalagens de costeletas de carne suína pré-cozidas, prolongando o shelf life durante o armazenamento (CUTTER, 2006).…”