Bacteria of the genus Alicyclobacillus pose serious quality problems for the juice processing industries that have sought effective alternatives for its control. The present study evaluated the ...effect of UV-C radiation on the reduction of spores and biofilm formation of Alicyclobacillus spp. on stainless steel and rubber surfaces using industrialized orange juice as a culture medium. Four reference Alicyclobacillus spp. species and different UV-C dosages were investigated. After exposed for 20 min (16.8 kJ/m2) to UV-C, the spores of Alicyclobacillus acidoterrestris, Alicyclobacillus herbarius, and Alicyclobacillus cycloheptanicus decreased drastically more of 4 log CFU/mL, with counts below the detection limit of the method (<1.7 log CFU/mL), while the Alicyclobacillus acidocaldarius spores were more sensitive to UV-C, once this spore reduction was observed within 15 min (12.6 kJ/m2). Morphological changes in the Alicyclobacillus acidoterrestris spores were observed by scanning electron microscopy. A reduction of biofilm formation was observed for all UV-C treatments, and the higher reductions (approximately 2 log CFU/mL) were found for the Alicyclobacillus acidocaldarius species after 30 min (26.2 kJ/m2), on the stainless steel and rubber surfaces. The results suggest that UV-C can be used to reduce the biofilm formation and could be a promising alternative for controlling Alicyclobacillus spp. spores in industrialized orange juice.
•Efficiency of UV-C radiation in reconstituted orange juice was examined.•Alicyclobacillus spp. are vulnerable to UV-C.•External morphological changes were observed with UV-C.•UV-C can be promising to treatment Alicyclobacillus spp. spores and biofilms.
This study aimed to evaluate the risk concerning child population's health because of the occurrence of AFM
in UHT milk, powdered milk (PM) and infant formulae (IF). Determination of AFM
was ...performed in 60 samples and evaluation of the mycotoxin exposure was carried out through the determination of the estimated daily intake (EDI), whereas risk characterization was evaluated with the calculation of the risk of Hepatocellular Carcinoma (HCC) and the Margin of Exposure (MOE). AFM
ranged from 150 to 1020 ng/kg, and all the positive samples exceeded the limits stablished by European Community. The EDI for AFM
ranged according to the age group of the population studied (0-5 years old) from 0.828 to 2.523, 0-2.113 and 0.029-0.833 ng/kg b. w./day in UHT, PM and IF, respectively. The number of HCC cases associated with AFM
exposure (0.0015 a 0.0045) was higher than the limit of 0.001 case/100,000. MOE values for AFM
were 728 to 239, considerably below the security margin of 10,000. These results point to a potential risk to the health of Brazilian child population exposed to AFM
in dairy products.
This study focuses on an alginate edible coating with oregano and rosemary essential oils (EO) as well as its application in a Fresh cheese. The practical application was carried out by analyzing ...microbial contents, centesimal composition, texture (shear force) and instrumental color, sensory acceptance and mass loss. The coatings containing rosemary EO retained minimal numbers of Coliforms (35ºC) during storage; thus, a positive effect of the coatings on improving the microbiological cheese quality was observed. Sensorial results were satisfactory for all edible coating samples (Acceptance Index > 77%) highlighting the one with oregano essential oil, proving that this coating can be an alternative to improve technological parameters of Fresh Cheese quality.
Alicyclobacillus spp. are spore forming bacteria that are often related to the deterioration of acidic products such as beverages and citrus juices. After the process of industrial pasteurization, ...the spore produced by the bacteria can germinate and the microorganism can grow, causing sensory abnormalities in the product. Alternative biopreservatives, such as the antimicrobial compounds, are of considerable importance to the food industry. Papain and bromelain are proteolytic enzymes derived from papaya and pineapple, respectively. These enzymes are widely used in medicine and in the pharmaceutical and food industries, but while some studies have described their antibacterial action, no studies of the Alicyclobacillus spp. exist. The aim of this study was to analyze the antibacterial effect of papain and bromelain on Alicyclobacillus spp. through 1) determining minimum inhibitory and bactericidal concentration (MIC and MBC); 2) determining the death time curve of the micro-organism in the presence and absence of enzymes; and 3) investigating the enzymatic mechanism on the microorganism. The antibacterial activity of enzymes in combination with nisin was also evaluated. The results showed that for the Alicyclobacillus acidoterrestris strain, the MIC of papain was 0.98μg/mL and the MBC was 3.91μg/mL, while the MIC of bromelain was 62.5μg/mL and the MBC was 250μg/mL. The concentration of 4×MIC for both the enzymes was sufficient to eliminate 4 logs of the micro-organism after 24h of incubation. Through the use of enzyme inhibitors specific for cysteine proteases, it was found that the antibacterial activity of papain and bromelain is not related to its proteolytic activity, but may be related to other activities, such as amidse and esterase. The synergistic activity of the enzymes revealed a fractional inhibitory concentration (FIC) level of 0.16. Combination with nisin revealed an FIC of 0.25 for papain and 0.19 for bromelain, indicating synergism between both compounds. The application of enzymes in reconstituted orange juice contaminated with A. acidoterrestris was found to be effective, as after 48h of incubation, at three different temperatures, the initial microbial population was eliminated. This study showed that the enzymes papain and bromelain have an antibacterial effect on A. acidoterrestris.
•Papain and bromelain showed effective antibacterial activity on Alicyclobacillus spp.•The action mechanism on A. acidoterrestris is not due to an enzymatic action.•Synergistic interaction between enzymes and with nisin was proven.•Tests in reconstituted orange juice demonstrated efficacy for use of this enzymes.
The objective of this study was to evaluate the effect of the initial microbial load, temperature and contact time on the biofilm formation of Alicyclobacillus acidoterrestris on stainless steel and ...natural food-grade rubber using orange juice as culture medium. The low initial load of A. acidoterrestris (2 log CFU/mL) led to biofilm formation on the stainless steel surface after 48 h of contact at 28 ºC and after 24 h at 45 ºC, and on natural food-grade rubber surface after 48 h of contact at both temperatures. The high initial microbial load (5 log CFU/mL) led to biofilm formation on stainless steel after 4 h of contact at 28 °C and 45 °C, while biofilm was formed on natural food-grade rubber after 8 h of contact at 28 °C and 4 h at 45 °C. The microbial load also affected the presence of spores in biofilm, which was observed on both surfaces only at high initial loads of A. acidoterrestris.
RESUMO: O objetivo deste estudo foi avaliar o efeito da carga microbiana inicial, temperatura e tempo de contato na formação de biofilme de Alicyclobacillus acidoterrestris em aço inoxidável e borracha natural de qualidade alimentar utilizando suco de laranja como meio de cultura. A baixa carga inicial de A. acidoterrestris (2 log UFC/mL) levou à formação de biofilme na superfície do aço inoxidável após 48 h de contato a 28 ºC e após 24 h a 45 ºC, e na superfície natural de borracha de qualidade alimentar após 48 h de contato nas duas temperaturas. A alta carga microbiana inicial (5 log UFC/mL) levou à formação de biofilme em aço inoxidável após 4 h de contato a 28 °C e 45 °C, enquanto o biofilme foi formado em borracha natural de qualidade alimentar após 8 h de contato a 28 °C e 4 h a 45 °C. A carga microbiana também afetou a presença de esporos no biofilme, o que foi observado em ambas as superfícies apenas com altas cargas iniciais de A. acidoterrestris.
The objective of this study was to evaluate the biofilm‐forming ability of Alicyclobacillus spp. isolates. Biofilm formation was evaluated under a stainless steel surface using orange juice as a ...culture medium at different temperatures (28 and 45 °C, 30 and 45 °C, and 45 and 60 °C) and contact times (24, 72, and 120 hr). The degree of hydrophobicity and the survival time of the different isolates on the abiotic surface were also investigated. Five Alicyclobacillus spp. isolates from the orange juice industry and a reference strain of Alicyclobacillus acidoterrestris 0244T were used. The biofilm formation of Alicyclobacillus was observed from 24 hr of contact in at least one temperature tested, as a function of the different incubation times and temperatures. Alicyclobacillus spp. presented variations in the degree of hydrophobicity. Surprisingly, two biofilm‐forming isolates (CCT 7230 and CCT 7346) were hydrophilic, with hydrophobicity index <20%, therefore, they are not necessarily related to cell hydrophobicity and adherence of Alicyclobacillus to the stainless steel surface. This study demonstrated that Alicycclobacillus spp. isolates from the industry can survive the processing conditions and form biofilms on contact surfaces.
Practical applications
Alicyclobacillus spp. may be present in the orange juice industry and form biofilms. In addition, it is known that the equipment is exposed to a wide temperature range for different periods of time and that poorly sanitized stainless steel equipment and surface can provide substrates for the formation of biofilms by Alicyclobacillus spp. Therefore, it is of the most importance to understand how these factors influence the adhesion and formation of Alicyclobacillus spp. in the processing of orange juice.
Pathogenic and deteriorating bacteria are a great concern to food safety. In this sense, the present study evaluated the fight against microbial contamination through the use of nanoparticles ...containing curcumin, in addition to analyzing the physical properties of these nanoparticles. Efficient curcumin encapsulation was determined by Fourier transform infrared spectra evaluation and differential scanning calorimetry. Transmission electron microscopy images showed irregular shaped nanoparticles with broad size distribution (20–250 nm). The antibacterial activity was considered satisfactory, since curcumin in the form of nanoparticles demonstrated antimicrobial and antibacterial activity superior to curcumin in its free form, against both pathogenic bacteria, such as Staphylococcus aureus (MIC 125 μg/mL), and deteriorates, such as Alicyclobacillus acidoterrestris (MIC 62.5 μg/mL). Since curcumin nanoparticles may be consumed as a food additive, the bioactive properties of the nanoencapsulated curcumin were also evaluated in relation to antioxidant capacity (Thiobarbituric acid reactive substances (TBARS) and oxidative hemolysis inhibition assays) and cytotoxicity against four carcinoma cell lines, as well as two non-tumor cells. As a proof of concept, nanoparticles were incorporated in orange juice, with the juice maintaining satisfactory pH, °Brix, and color stability, during three days of storage (8 °C).
•Curcumin nanoparticles showed an antimicrobial activity superior to curcumin in its pure form.•Curcumin nanoparticles also presented superior action against the spores than in natura curcumin.•DSC and FTIR demonstrated curcumin in its amorphous phase, due to its interaction with PVP.•Encapsulation reduced the cytotoxic effect of curcumin.•The nanoparticles presented stability when applied to orange juice.
Alicyclobacillus acidoterrestris is a bacteria capable of spoiling industrialized orange juice, making it a problem for the beverage industry. This study evaluated the effect of UV-C radiation in ...combination with nisin in the reduction of A. acidoterrestris spores using reconstituted orange juice. A. acidoterrestris spores were treated with nisin (7.81 and 15.62 μg/mL) in combination with different doses of UV-C (from 2.52 to 12.6 kJ/m2). The presence of vitamins in the juice after the treatments was investigated by UHPLC-HRMS using a ultra high performance liquid chromatography system. The combination of UV-C and nisin treatment showed counts below the detection limit of the method (<1.7 log CFU/mL) both at time 6 min (5.04 kJ/m2) with 7.81 μg/mL nisin and at time 3 min (2.52 kJ/m2) with 15.62 μg/mL nisin (p < 0.05). Ascorbic acid was found in control and 3-min UV-C samples, but with 15 min of treatment the vitamin was not detected. Thiamine was found in the three samples analyzed (T0, T3 and T15). Treatment with UV-C combined with low dose nisin (2.52 kJ/m2) eliminated spores without degrading the analyzed juice vitamins and is a promising alternative for the beverage industry.
•Alicyclobacillus acidoterrestris leads to economic losses in food industry.•Alternative methods, as UV-C, promote the maintenance of the quality and microbiology control of juice.•Combination of UV-C and nisin showed potential spore reduction of A. acidoterrestris.•The vitamin C present in orange juice was preserved after the treatments.
The objective of this study was to evaluate the antimicrobial effectiveness of cinnamaldehyde (CIN) and potassium sorbate (P.S.), alone and in combination, against Salmonella Typhimurium and ...Staphylococcus aureus in vitro and in apple jam. Antimicrobial activity in vitro was investigated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), time-kill assay and determination of fractional inhibitory concentration index. CIN MIC and MBC was 312 μg/mL. P.S. MIC and MBC were 2500 and 5000 μg/mL, respectively, against S. Typhimurium; and 10,000 and 20,000 μg/mL, respectively, against S. aureus. The compounds combined exhibited a synergistic effect (FIC < 0.5), inhibiting S. Typhimurium growth after 12 h and S. aureus after 24 h. The effect of CIN and P.S., at sub-inhibitory concentrations, against bacterial strains in apple jam was evaluated during storage. Physicochemical and sensory analyses were also performed. No cultivable S. Typhimurium or S. aureus cells were recovered in apple jam supplemented with CIN + P.S. on the third day of storage. The addition of CIN and P.S. did not affect the physicochemical properties and sensory evaluation showed a score above 7.0. CIN and P.S. association at sub-inhibitory concentrations was effective in controlling foodborne pathogens and improved the shelf life of apple jam.
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