Young bamboo flour as a substitute for emulsifying salts in requeijão cremoso processed cheese and the effect on the quality parameters.

The effect of the substitution of emulsifying salt by the young bamboo flour (BF) (0, 25, 50, 75, 100 % w/w) on requeijão cremoso processed cheese [REQ, REQ 25, REQ 75 REQ 100]) processing was investigated. Gross composition, calcium and sodium values, functional properties (melting rate), color parameters (L, a*, b*, C*, and Whiteness Index, WI), texture profile, fatty acid profile, volatile organic compounds (VOCs), and sensory profiling were evaluated. No effect was observed on the gross composition; however, sodium and melting rate values were decreased, and calcium values presented the opposite behavior. BF could modify the optical parameters, observing an increase in WI values. Higher BF addition increased hardness and lowered elasticity, and regarding the fatty acid profile, there is no significant difference. Different volatile compounds were noted in a proportional form with the BF addition, which was reflected in similar sensory acceptance for REQ 25 and control samples. Although some aspects require further in-depth studies, using BF as a substitute for emulsifying salt in requeijão cremoso processed cheese appears to be a viable option, especially when considering partial replacements.

Development and application of a real-time polymerase chain reaction method for quantification of Escherichia coli in oysters (Crassostrea gigas).

Oysters are important mariculture species worldwide. Because of their filter-feeding behaviors, oysters can accumulate microorganisms, including pathogens, from surrounding water and concentrate bacteria in high numbers. Rapid and suitable methods for quantification of Escherichia coli in oysters are necessary considering that oysters are perishable foods often consumed raw and some countries use E. coli as the regulatory limit. The objective of this study was to develop a qPCR method for quantification of E. coli in oysters. Additionally, different methods were evaluated for DNA extraction from oyster samples and the more reliable method was chosen. Primers and probe were designed targeting uidA gene of E. coli and shown to specifically amplify DNA from E. coli. Standard curves with bacterial DNA extracted from oysters samples artificially inoculated with E. coli were conducted. A good correlation was noticed when the qPCR method was compared to a culture method in oyster samples. This is the first report of a method exclusively developed for direct quantification of E. coli in oyster, the method showed to be suitable for quantification of E. coli in oysters and could be useful in routine analyses, as it requires less time than the culture method.

Genotypic and phenotypic characterization of Escherichia coli isolated from mollusks in Brazil and the United States.

The aim of this study was to determine the serogroups, antimicrobial resistance and genetic diversity of Escherichia coli isolates from samples of bivalve mollusks collected along Santa Catarina coast, Brazil, and from the Chesapeake Bay, Maryland, USA. One hundred forty-one E. coli isolates were characterized for serogroups with 181 specific O antisera and antimicrobial susceptibility using the disk diffusion method. The genetic diversity was assessed using pulsed-field gel electrophoresis (PFGE). The results showed that among the isolates, 19.9% were classified as multi-drug resistant (MDR) and resistance was most frequently observed to cephalothin, nitrofurantoin, and ampicillin. The predominant serogroups were O6, O8, and O38. Some serogroups were recognized as pathogenic E. coli. PFGE dendrograms indicated extensive genetic diversity among the isolates. Although characteristics of the E. coli isolates were highly variable, it is important to note that E. coli belonging to pathogenic serogroups and MDR isolates are present in mollusks of both study areas. This is the first report on the phenotypic and genotypic characterization of E. coli from mollusks from Santa Catarina and the Chesapeake Bay that should encourage studies focusing on comparison of isolates across countries.

Effects of dietary replacement of fishmeal by mealworm meal on muscle quality of farmed shrimp Litopenaeus vannamei.

This study investigated the muscle quality of the shrimp Litopenaeus vannamei fed on a diet containing different proportions of mealworm meal (MW) (0, 25, 50, 75 and 100%) as a substitute for fishmeal, which is the normal diet used in shrimp commercial production. The proximate composition, fatty acid profile, colour and texture of the shrimps were evaluated. Moisture, protein, and ash content of shrimp muscle were not significantly altered when fishmeal was replaced by MW (p>0.05). However, the replacement resulted in a linear increase in lipid content (p<0.05). The fatty acid composition of the experimental diets directly mirrored the fatty acid composition of shrimp muscle. The absence of long-chain polyunsaturated fatty acids in MW composition resulted in a linear decrease in eicosapentaenoic and docosahexaenoic fatty acids in shrimp muscle with increasing levels of MW in the diet. The n-3/n-6 ratio ranged from 0.50 to 0.67. Colour and firmness were unchanged between the treatments. Although the use of MW as a fishmeal substitute in L. vannamei diets has affected the lipid and fatty acid composition of shrimp muscle, from a human nutritional perspective, the lipid content of the shrimps is considered low and the n-3/n-6 ratio remained within the human dietary requirements. Therefore the use of a mealworm diet for shrimp production is a viable alternative to increasingly expensive fishmeal based diets.

Effect of the incorporation of Bifidobacterium BB-12 microencapsulated with sweet whey and inulin on the properties of Greek-style yogurt.

The effect of the addition of Bifidobacterium BB-12 microencapsulated by spray drying with sweet whey and inulin on the microbiological, physicochemical and texture properties of Greek-style yogurt was evaluated during 28 days of storage. The survival of this probiotic under simulated gastrointestinal conditions was assessed after this storage time. Three formulations of Greek-style yogurt were produced: Control (with free cells); SW (with microcapsules produced only with sweet whey); and SWI (with microcapsules produced with sweet whey and inulin). The counts of Bifidobacterium BB-12 remained stable during storage in the Control yogurt and in the SW yogurt, while a slight decrease occurred in the SWI yogurt. Nevertheless, the addition of microcapsules improved the survival of S. thermophilus and L. bulgaricus in the SW yogurt after 14 days of storage. In general, incorporation of microcapsules into Greek-style yogurt affected specific physicochemical and textural properties of the samples. A decrease in the probiotic survival rate during gastrointestinal simulation was observed for all samples; however, it was more pronounced in the SWI yogurt. Even though the protective effect of the microcapsules was not evident, the results showed that Greek-style yogurt is a promising carrier for incorporation of Bifidobacterium BB-12.

A control method to inspect the compositional authenticity of Minas Frescal cheese by gel electrophoresis.

This study introduces a qualitative method to inspect the compositional authenticity of white nonripened cheeses like Minas Frescal, a typical Brazilian cheese, especially when irregular replacement of milk by whey is suspected. A sodium dodecyl sulfate gel electrophoresis (SDS-PAGE) method, followed by image densitometry, was validated. Cheeses were freeze-dried to electrophoresis, and ß-lactoglobulin (ß-LG) was chosen as the adulteration marker. In gel trypsin digestion followed by matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry provided its identification. Cheeses with a minimum of 14 mg·g(-1) of ß-LG are considered to be adulterated. The method shows satisfactory precision with a detection limit of 7 mg·g(-1). Forty-two commercial samples from inspected establishments were then assessed and subjected to cluster analysis. Compliant and noncompliant groups were set with 24 (57%) authentic samples and 18 (43%) adulterated samples, respectively, showing that proper analytical monitoring is required to inhibit this practice.