ABSTRACT
Escherichia coli O157:H7 is a toxigenic serotype of E. coli and has been associated with foodborne outbreaks involving meat products, vegetables and fresh produces worldwide. Salts for curing are usually employed as antimicrobials in the production of pork sausages. However, salts do not have a significant inhibitory effect on enterobacteria. Due to the growing demand for natural foods, the use of essential oils has been proposed as natural antimicrobials in food. This study aimed to evaluate the effects of garlic essential oil (GO) and allyl isothiocyanate (AITC) against E. coli O157:H7 in vitro and in pork sausage. The Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of these oils, alone and in combination, against E. coli O157:H7 were determined. Pork sausage was inoculated with 8log CFU/g E. coli O157:H7 and different combinations of GO and AITC. A control group was performed without essential oils. Sausages were packaged and stored at 6°C for 20 days. E. coli O157:H7 population and instrumental color (L*, a*, b*, C* and hue) determinations were performed at 5-day intervals. AITC showed lower MIC and MBC than GO. When combined, AITC and GO showed a synergistic effect. Treatments T3 and T4 showed 1,01log CFU and 1,87log CFU reduction of E. coli O157:H7 compared to control. The redness and the chroma of sausages treated with AITC and GO increased during storage. Together, GO and AITC caused minor changes in taste and flavor of sausages, and were able to reduce the population of E. coli O157:H7 and to maintain the red color of sausage during storage.(AU)
Escherichia coli O157:H7 é um sorotipo toxigênico de E. coli associado mundialmente a surtos de doenças alimentares causadas por produtos cárneos. Os sais de cura são normalmente empregados como antimicrobianos na fabricação de linguiças, entretanto, possuem pouco efeito inibitório sobre enterobactérias como E. coli. Devido à crescente demanda por produtos naturais, o uso de óleos essenciais tem sido proposto como antimicrobiano natural em alimentos. O objetivo deste estudo foi avaliar os efeitos do óleo essencial de alho (GO) e isotiocianato de alila (AITC) contra E. coli O157:H7 in vitro e em linguiça. As concentrações inibitória mínima (MIC) e bactericida mínima (MBC) dos óleos, isolados e em combinação, contra E. coli O157:H7 foram determinadas in vitro. Lotes de linguiça foram inoculados com 8log UFC/g E. coli O157:H7 e diferentes concentrações de GO + AITC e estocados a 6°C por 20 dias. Contagens de E. coli O157:H7 e determinação de cor instrumental (L*, a*, b*, C* e hue) foram realizadas a cada 5 dias. Nos testes in vitro, AITC mostrou maior ação inibitória que GO, havendo efeito sinérgico dos óleos quando combinados. Os tratamentos T3 e T4 mostraram redução de 1,01log UFC e 1,87log UFC de E. coli O157:H7 comparados ao controle. A intensidade de cor vermelha e a saturação de cor aumentaram durante a estocagem nas linguiças adicionadas de óleos essenciais. A adição dos óleos GO + AITC causou mínima alteração no sabor e na aparência das linguiças e foi capaz de reduzir a população de E. coli O157:H7 no produto cárneo, mostrando potencial para uso como conservante natural nesse tipo de alimento.(AU)
Subject(s)
Oils, Volatile , Meat Products/microbiology , Garlic/chemistry , Isothiocyanates , Escherichia coli O157 , Anti-Bacterial Agents , SwineABSTRACT
Escherichia coli O157:H7 is a toxigenic serotype of E. coli and has been associated with foodborne outbreaks involving meat products, vegetables and fresh produces worldwide. Salts for curing are usually employed as antimicrobials in the production of pork sausages. However, salts do not have a significant inhibitory effect on enterobacteria. Due to the growing demand for natural foods, the use of essential oils has been proposed as natural antimicrobials in food. This study aimed to evaluate the effects of garlic essential oil (GO) and allyl isothiocyanate (AITC) against E. coli O157:H7 in vitro and in pork sausage. The Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of these oils, alone and in combination, against E. coli O157:H7 were determined. Pork sausage was inoculated with 8log CFU/g E. coli O157:H7 and different combinations of GO and AITC. A control group was performed without essential oils. Sausages were packaged and stored at 6°C for 20 days. E. coli O157:H7 population and instrumental color (L*, a*, b*, C* and hue) determinations were performed at 5-day intervals. AITC showed lower MIC and MBC than GO. When combined, AITC and GO showed a synergistic effect. Treatments T3 and T4 showed 1,01log CFU and 1,87log CFU reduction of E. coli O157:H7 compared to control. The redness and the chroma of sausages treated with AITC and GO increased during storage. Together, GO and AITC caused minor changes in taste and flavor of sausages, and were able to reduce the population of E. coli O157:H7 and to maintain the red color of sausage during storage.
Escherichia coli O157:H7 é um sorotipo toxigênico de E. coli associado mundialmente a surtos de doenças alimentares causadas por produtos cárneos. Os sais de cura são normalmente empregados como antimicrobianos na fabricação de linguiças, entretanto, possuem pouco efeito inibitório sobre enterobactérias como E. coli. Devido à crescente demanda por produtos naturais, o uso de óleos essenciais tem sido proposto como antimicrobiano natural em alimentos. O objetivo deste estudo foi avaliar os efeitos do óleo essencial de alho (GO) e isotiocianato de alila (AITC) contra E. coli O157:H7 in vitro e em linguiça. As concentrações inibitória mínima (MIC) e bactericida mínima (MBC) dos óleos, isolados e em combinação, contra E. coli O157:H7 foram determinadas in vitro. Lotes de linguiça foram inoculados com 8log UFC/g E. coli O157:H7 e diferentes concentrações de GO + AITC e estocados a 6°C por 20 dias. Contagens de E. coli O157:H7 e determinação de cor instrumental (L*, a*, b*, C* e hue) foram realizadas a cada 5 dias. Nos testes in vitro, AITC mostrou maior ação inibitória que GO, havendo efeito sinérgico dos óleos quando combinados. Os tratamentos T3 e T4 mostraram redução de 1,01log UFC e 1,87log UFC de E. coli O157:H7 comparados ao controle. A intensidade de cor vermelha e a saturação de cor aumentaram durante a estocagem nas linguiças adicionadas de óleos essenciais. A adição dos óleos GO + AITC causou mínima alteração no sabor e na aparência das linguiças e foi capaz de reduzir a população de E. coli O157:H7 no produto cárneo, mostrando potencial para uso como conservante natural nesse tipo de alimento.
Subject(s)
Garlic/chemistry , Anti-Bacterial Agents , Isothiocyanates , Meat Products/microbiology , Oils, Volatile , SwineABSTRACT
ABSTRACT: Escherichia coli O157:H7 is a toxigenic serotype of E. coli and has been associated with foodborne outbreaks involving meat products, vegetables and fresh produces worldwide. Salts for curing are usually employed as antimicrobials in the production of pork sausages. However, salts do not have a significant inhibitory effect on enterobacteria. Due to the growing demand for natural foods, the use of essential oils has been proposed as natural antimicrobials in food. This study aimed to evaluate the effects of garlic essential oil (GO) and allyl isothiocyanate (AITC) against E. coli O157:H7 in vitro and in pork sausage. The Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of these oils, alone and in combination, against E. coli O157:H7 were determined. Pork sausage was inoculated with 8log CFU/g E. coli O157:H7 and different combinations of GO and AITC. A control group was performed without essential oils. Sausages were packaged and stored at 6°C for 20 days. E. coli O157:H7 population and instrumental color (L*, a*, b*, C* and hue) determinations were performed at 5-day intervals. AITC showed lower MIC and MBC than GO. When combined, AITC and GO showed a synergistic effect. Treatments T3 and T4 showed 1,01log CFU and 1,87log CFU reduction of E. coli O157:H7 compared to control. The redness and the chroma of sausages treated with AITC and GO increased during storage. Together, GO and AITC caused minor changes in taste and flavor of sausages, and were able to reduce the population of E. coli O157:H7 and to maintain the red color of sausage during storage.
RESUMO: Escherichia coli O157:H7 é um sorotipo toxigênico de E. coli associado mundialmente a surtos de doenças alimentares causadas por produtos cárneos. Os sais de cura são normalmente empregados como antimicrobianos na fabricação de linguiças, entretanto, possuem pouco efeito inibitório sobre enterobactérias como E. coli. Devido à crescente demanda por produtos naturais, o uso de óleos essenciais tem sido proposto como antimicrobiano natural em alimentos. O objetivo deste estudo foi avaliar os efeitos do óleo essencial de alho (GO) e isotiocianato de alila (AITC) contra E. coli O157:H7 in vitro e em linguiça. As concentrações inibitória mínima (MIC) e bactericida mínima (MBC) dos óleos, isolados e em combinação, contra E. coli O157:H7 foram determinadas in vitro. Lotes de linguiça foram inoculados com 8log UFC/g E. coli O157:H7 e diferentes concentrações de GO + AITC e estocados a 6°C por 20 dias. Contagens de E. coli O157:H7 e determinação de cor instrumental (L*, a*, b*, C* e hue) foram realizadas a cada 5 dias. Nos testes in vitro, AITC mostrou maior ação inibitória que GO, havendo efeito sinérgico dos óleos quando combinados. Os tratamentos T3 e T4 mostraram redução de 1,01log UFC e 1,87log UFC de E. coli O157:H7 comparados ao controle. A intensidade de cor vermelha e a saturação de cor aumentaram durante a estocagem nas linguiças adicionadas de óleos essenciais. A adição dos óleos GO + AITC causou mínima alteração no sabor e na aparência das linguiças e foi capaz de reduzir a população de E. coli O157:H7 no produto cárneo, mostrando potencial para uso como conservante natural nesse tipo de alimento.
ABSTRACT
Harvesting of Brazil nuts not only helps to preserve the Amazon rainforest but also provides income to individuals who would otherwise have little means of making a livelihood. Recently, the European Community has tightened the quality requirements for Brazil nuts, particularly with regard to aflatoxin levels and microbiological contamination. The objectives of this research were to gain a better understanding of the origin of aflatoxins on Brazil nuts and to microbiologically evaluate some of the operations involved in processing. In this regard, five Brazil nut pods were aseptically picked from trees located in each of three concessions of the Peruvian Amazon rainforest (Madre de Dios province). The exteriors of the pods and the nuts were examined for yeast and molds, including Aspergillus flavus and Aspergillus parasiticus, and for bacteria, including Salmonella and Escherichia coli. Brazil nuts obtained from various commercial process operations located in Peru were similarly evaluated. Exteriors of all Brazil nut pods did not contain A. parasiticus, and only pods from one concession yielded A. flavus isolates. All isolates tested were aflatoxigenic (630 to 915 ppb total aflatoxin). Coliforms, E. coli, and salmonellae were not recovered from any of the pods. Whole, in-shell nuts obtained after opening the pods yielded no A. flavus or A. parasiticus. Aflatoxins were not detected (detection limit 1.75 ppb) in any of the nuts. Whole, in-shell and shelled nuts from various process operations were all positive for A. flavus but negative for E. coli and salmonellae. Soaking of whole, in-shell nuts before cracking or shelling increased coliform numbers, whereas levels of A. flavus decreased. In order to gain a better understanding of the sanitary performance of the unit process operations, additional evaluations should be conducted on product lots processed on different days. Also, the microbiology of product processed from common lots should be followed through the various unit operations and compared.