Microbial resistance to sanitizers in the food industry: review

Hygiene programs which comprise the cleaning and sanitization steps are part of the Good Hygiene Practices (GHP) and are considered essential to ensure food safety and quality. Inadequate hygiene practices may contribute to the occurrence of foodborne diseases, development of microbial resistance to sanitizers, and economic losses. In general, the sanitizer resistance is classified as intrinsic or acquired. The former is an inherent characteristic, naturally present in some microorganisms, whereas the latter is linked to genetic modifications that can occur at random or after continuous exposure to a nonnormal condition. The resistance mechanisms can involve changes in membrane permeability or in the efflux pump, and enzymatic activity. The efflux pump mechanism is the most elucidated in relation to the resistance caused by the use of different types of sanitizers. In addition, microbial resistance to sanitizers can also be favored in the presence of biofilms due to the protection given by the glycocalyx matrix and genetic changes. Therefore, this review aimed to show the main microbial resistance mechanisms to sanitizers, including genetic modifications, biofilm formation, and permeability barrier.

Response surface optimization of phenolic compounds extraction from camu-camu (Myrciaria dubia) seed coat based on chemical properties and bioactivity

Food companies should comply with the requirements of a zero-waste concept to adapt to the circular economy requirements. In fruit companies, usually seeds are discarded without proper utilization and extraction of the bioactive compounds. Fruit seeds are sources of chemical compounds that can be extracted, studied, and applied in high value-added products. Thus, in this work the experimental conditions for the water extraction of phenolic compounds from camu-camu (Myrciaria dubia) seed coat were optimized using a central composite design and the desirability function. Total phenolic content (TPC), and condensed tannins (CT), DPPH radical scavenging activity, ferric reducing antioxidant capacity (FRAP), Folin-Ciocalteu reducing capacity (FCRC), and Cu²⁺ chelating ability were assessed. Seed coat extracted for 51.1 min using a 1:34.1 solid:liquid ratio was the optimal condition to extract 6,242 mg gallic acid equivalent (GAE)/100 g of TPC and 695 mg catechin equivalent (CE)/100 g of CT. The optimized extract displayed free-radical scavenging activity, reducing properties and ability to chelate Cu²⁺ , and inhibited the growth of Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium, Salmonella Enteritidis, Bacillus cereus, and Staphylococcus aureus. Additionally, the lyophilized water extract inhibited the in vitro activity of α-amylase, α-glucosidase, and angiotensin converting enzyme and showed cytotoxic effects towards Caco-2, A549, and HepG2 cancer cells, but no cytotoxicity towards IMR90 cells. Vescalagin, castalagin, and 3,4-dihydroxybenzoic acid were the major phenolic compounds identified in the optimized extract. In conclusion, the optimized camu-camu seed coat water extract is a rich source of phenolic compounds with antioxidant, antidiabetic, antihypertensive, and antiproliferative effects. PRACTICAL APPLICATION: Camu-camu fruit pulp and seeds have been studied for their phenolic composition and bioactivity. However, seeds are usually discarded and represent an environmental problem in South American countries. We presented a methodological overview on the extraction optimization of the phenolic compounds from camu-camu seed coat and studied the bioactivity of the optimized extract using chemical, enzymatic, and cell-based experiments. Results can be used by camu-camu processors to obtain a phenolic-rich extract for industrial applications, without any further processing.

Flaxleaf Fleabane Leaves (Conyza bonariensis), A New Functional Nonconventional Edible Plant?

This work aimed to investigate the phytochemical composition, nutritional value, antioxidant, antihemolytic, antihyperglycemic, and antiproliferative activities of flaxleaf fleabane (Conyza bonariensis) leaves. Different concentrations of water and ethanol (0:100, 25:75, 50:50, 75:25, and 100:0 v/v) were used in the extraction process and results showed that the hydroalcoholic extract (50:50 v/v) presented the highest total phenolics, ortho-diphenolics, Folin-Ciocalteu reducing capacity, FRAP, and Fe²⁺ chelating ability values. Flaxleaf fleabane leaves (FFL) contained 19.6 g/100 g of fibers and 26 g/100 g of proteins. Ellagic acid, procyanidin A2, caffeic, rosmarinic, gallic, and 2,5-dihydroxybenzoic acids were the main phenolics. This phenolic-rich extract inhibited the lipid oxidation of Wistar rat brain (IC₅₀ = 863.0 mg GAE/L), inhibited α-glucosidase activity (IC₅₀ = 435.4 µg/mL), protected human erythrocytes against mechanical hemolysis at different osmolarity conditions, and showed cytotoxic/antiproliferative effects against human ileocecal adenocarcinoma cells (HCT8; IC₅₀ = 552.6 µg/mL) but no cytotoxicity toward noncancerous human lung fibroblast (IMR90). Overall, FFL showed potential to be explored by food companies to be a source of proteins, natural color substances, and phenolic compounds. PRACTICAL APPLICATION: Flaxleaf fleabane leaves (FFL) are usually burnt or partially given to cattle, without a proper utilization as a source of nutrients for human nutrition. Here, we studied the nutritional composition, phenolic composition, and toxicological aspects of FFL using different biological protocols. FFL was proven to be a rich source of proteins and dietary fibers and showed antioxidant activity measured by chemical and in vitro biological assays. Additionally, as it did protected human red cells and did not show cytotoxicity, we assume FFL has relative safety to be consumed as a nonconventional edible plant.

Comparison of serum hormone levels of captive and free-living maned wolves Chrysocyon brachyurus

Serum hormone levels were compared between captive and free-living maned wolves and seasonal variations of sex hormones were studied. Blood samples were collected from 16 male and 26 female adult animals from Brazilian zoos, and from 30 male and 24 female free-living adults to determine serum progesterone and testosterone by radioimmunoassay. Serum testosterone concentrations varied (P < 0.05) across seasons for 16 captive males, being higher in autumn (2184.7 +/- 355.1 pg/mL) than in summer (1080.7 +/- 205.4 pg/mL), winter (1270.1 +/- 276.6 pg/mL) and spring (963.9 +/- 248.1 pg/mL), although they did not differ between summer, winter and spring. Testosterone concentration of 30 free-living males differed (P < 0.05) between autumn (824.1 +/- 512.2 pg/mL), winter (14.4 +/- 8.0 pg/mL) and spring (151.9 +/- 90.5 pg/mL). Comparison between captive and free-living animals showed no difference in autumn (P > 0.05). Sixteen captive males showed higher testosterone concentration during winter and spring compared with 30 free-living animals (P < 0.05). Progesterone concentration varied among seasons in 26 captive females (P < 0.05), being higher in autumn (15.3 +/- 3.1 ng/mL) than in summer (6.6 +/- 1.5 ng/mL), winter (5.3 +/- 3.1 ng/mL) and spring (4.3 +/- 0.7 ng/mL). Progesterone concentration of 24 free-living females varied between autumn (17.1 +/- 6.0 ng/mL) and winter (1.7 +/- 0.3 ng/mL) (P < 0.05), but we could not obtain data for spring or summer. No difference in progesterone levels was observed between captive and free-living females in autumn and winter.

A multiplex PCR assay for the simultaneous detection and discrimination of the sevenEimeriaspecies that infect domestic fowl

This study reports the development of a novel multiplex PCR assay based on SCAR (Sequence-Characterised Amplified Region) markers for the simultaneous diagnosis of the 7Eimeriaspecies that infect domestic fowl. Primer pairs specific for each species were designed in order to generate a ladder of amplification products ranging from 200 to 811 bp. Sensitivity tests for each species were carried out, showing a detection threshold of 1–5 pg, which corresponds approximately to 2–8 sporulated oocysts. Distinct isolates of the 7Eimeriaspecies from different geographical sources were tested and successfully detected by the assay. All the species were amplified homogeneously, whether or not one of them was present in a high quantity, indicating that there was no cross-interference. The assay was also tested with different sources ofTaqDNA polymerase and thermocycler models, confirming the high reproducibility of the reaction. The economy of consumables and labour represented by a single-tube reaction greatly facilitates the molecular diagnosis of a large number of samples, making it appropriate for field epizootiological surveys. We propose the use of this multiplex PCR assay as a rapid and cost-effective diagnostic method for the detection and discrimination of the 7Eimeriaspecies that infect domestic fowl.

Detection of cow milk in goat milk by polyacrylamide gel electrophoresis

Pasteurized goat milk was adulterated with increasing proportions of cow milk and submitted to polyacrylamide gel electrophoresis. A frontal band, missing from the pattern of genuine goat milk and possessing the same electrophoretic mobility as bovine alpha S1-casein, was expressed. The area of this zone was directly proportional to the amount of cow milk added to the goat milk.