Bacteriological quality of “doubles” sold by street vendors in Trinidad and the attitudes, knowledge and perceptions of the public about its consumption and health risk

The bacteriological loads of “bara”, “channa”, condiments/spices and ready-to-consume “doubles” sold by street vendors in St. George and Caroni counties of Trinidad were determined. Questionnaires were administered to 100 vendors from both counties to determine which of their practices had effect on the bacteriological quality of the products. In addition, a total of 300 randomly selected members of the public in both counties were interviewed using questionnaires, to assess their attitudes, knowledge and perceptions concerning “doubles” consumption. Of a total of 196 samples each of “bara”, “channa”, condiments/spices and ready-to-eat “doubles” tested, the log₁₀ mean (±SD) total aerobic plate count (TAPC) per g was 4.87±5.51, 5.79±6.61, 6.26±6.77 and 6.88±7.91, respectively. The difference was statistically significant (P<0.05; χ²). Applying a recommended maximum standard of log₁₀ TAPC per g of 5.00, 10 (5.1%), 19 (9.7%), 57 (29.1%) and 78 (39.8%) of 196 samples of “bara”, “channa”, condiments/spices and ready-to-consume “doubles”, respectively, were deemed unfit for human consumption. Vendor practices, which significantly affected the prevalence of unfit “doubles” were re-use of leftover product (P=0.01), wearing of hand gloves (P=0.02), availability of water at sale outlet (P=0.0008) and source of water (P=0.0008). Consumption of “doubles” was more common amongst East Indians (69.2%) than other races (30.8%) (P<0.001) and amongst individuals who were aware that “doubles” can cause food-poisoning (61.4%) compared with individuals who did not have the awareness (36.0%) (P<0.03). Age, gender and occupational status of individuals did not significantly (P>0.05) affect consumption of “doubles”. The high prevalence of ready-to-consume “doubles” assessed unfit for human consumption coupled with a significantly higher proportion of consumers than non-consumers being aware that the product could cause food-poisoning, definitely poses a health risk to consumers of “doubles” in the population. Enforcement of sanitary practices during the preparation and sale of “doubles” should reduce the health risk.     

Impact of Annealing on the Physicochemical Properties of Unfermented Cassava Starch (“Polvilho Doce”)

Unfermented cassava starch (“polvilho doce”) was subject to annealing treatment at 50°C for 24, 48, 96, 120, 168 and 192 h, in 1:5 starch to water ratio. The annealing treatment changed the internal structure of “polvilho doce” at increasing treatment time. Peak viscosities decreased significantly, denoting that there was a decrease in leaching of amylose from the granules. The pasting temperatures were increased, setback and breakdown were reduced while hold and final viscosities increased, showing an improvement of the stability of the paste. Swelling power and solubility were reduced at all temperatures and the solubility at 55°C was zero after 120 h of treatment. The DSC data for T_o, T_p, T_c and ΔH increased and the gelatinization range was narrowed. The X‐ray diffractograms changed from C_A to A pattern (samples annealed for 48, 96, 120, 168 and 192 h), denoting an increase in organization of double helices of amylopectin. Annealing imparts to the samples some waxy starches characteristics which can be very useful in the food industry.     

Gas chromatographic–mass spectrometric characterisation of the Italian Protected Designation of Origin “Altamura” bread volatile profile

Dynamic headspace extraction technique coupled to the gas chromatography–mass spectrometry analysis was applied to characterize volatile compounds of both crust and crumb of the Protected Designation of Origin Italian durum wheat sourdough “Altamura” bread. Volatile compounds of crust and crumb were characterized and statistically compared and their relative abundance was also calculated. A total of 89 compounds belonging to different chemical classes were identified in the crust. More abundant compounds detected in the crust were ethanol (20 ± 6%), 2-furfural (14 ± 7%) and 3-methyl-1-butanol (9 ± 5%). A lower number of volatile compounds (74) was identified in crumb, among which ethanol (32 ± 7%), 3-methyl-1-butanol (23 ± 6%) and 3-pentanol (7 ± 3) were the most abundant. The influence of different baking modes (wood- or gas-fired) on volatile compounds, macroscopic appearance and selected physico-chemical parameters (colour and texture) of bread samples were also evaluated.

Samples baked in wood-fired oven showed larger amount of volatile compounds such as furans and aldehydes that could positively influence the flavour of the product.

Crust of wood-fired breads showed higher amounts of compounds from Maillard reaction, resulting in harder and browner breads than gas-fired samples. Macroscopic appearance of crumb of wood-fired breads showed higher percentages of larger pores, being also less hard and cohesive than gas-fired samples.     

THE BREWING POTENTIAL OF “ACHA” (DIGITARIA EXILIS) MALT COMPARED WITH PEARL MILLET (PENNISETUM TYPHOIDES) MALTS AND SORGHUM (SORGHUM BICOLOR) MALTS

The malting and brewing characteristics of millets (Pennisetum typhoides and Digitaria exilis) and sorghum (Sorghum bicolor) were compared. Diastase, α-amylase, amyloglucosidase and proteases increased with malting time and the increase was associated with the modification. Development of hydrolytic enzymes was significantly higher in pearl millet and Digitaria exilis (“acha”) than in sorghum at P ≥ 0.01. The major starch degrading enzyme in the three varieties of pearl millet (SE composite, SE.13 and SE 2124) was α-amylase. On the other hand, β-amylase was the major starch degrading enzyme in “acha” (Digitaria exilis) which is similar to the pattern in barley. Gibberellic acid had a stimulating effect on the diastatic activity of pearl millets, Digitaria exilis (“acha”) and sorghum (KSV-4), but inhibited the diastatic activities of sorghum (Farafara). Gibbereltic acid inhibited the proteolytic activities in all the pearl millet varieties, Digitaria exilis and sorghum varieties. Potassium bromate had little or no effect in the reduction of malting losses. Although “acha” (Digitaria exilis) had a high β-amylase content, a high malting loss makes it uneconomical to brew with “acha” mart. A blend of “acha” malt with pearl millet malt or sorghum malt (composite malt) will produce a malt of the same profile as barley malt and this will enhance the quality of sorghum and pearl millet malt during the mashing process. Wort quality of all the samples was suitable for brewing conventional beer.     

Etude des parametres de controle et de commande du procede de deshydratation–impregnation par immersion, sur systeme probatoire automatise: application au traitement des pommes “Golden”

The work presented here is a study aiming at the control and checking of dewatering and impregnation soaking process (DISP). The studies are carried out using an automatic experimental system. Apples of the “Golden” variety are used exclusively. Two kinds of agitation system are studied; mechanical agitation using a vertical screw without an end, and hydraulic agitation. There is hardly any difference between the two kinds of agitation; parameter variations are almost the same. These results are compared with those obtained in agitated thermostated water-bath system and they show that mass transfers are better on the experimental system than with the water-bath system. Temperature influences were studied for the agitated thermostated water-bath system only. They show that the increase of temperature favours water loss and sugar intake. We have shown that during experiments with old syrup, only the conductivity of syrup is higher but kinetics of water loss, solute intake and weight reduction are not significantly affected.     

Evaluation of microbial transglutaminase and ribose cross-linked soy protein isolate-based microcapsules containing fish oil

Soy protein isolate (SPI)-based microcapsules containing fish oil were prepared using a modified coacervation method followed by cross-linking treatments. The procedure yielded 95–98% microcapsules containing 0.5–0.6 g fish oil/g capsule with a volume mean diameter ranged from ~ 260 to ~ 280 μm. Four types of microcapsules produced were SPI with sucrose (MC-C/S), SPI with ribose (MC-C/R), SPI with sucrose and microbial transglutaminase (MC-MTG/S) and SPI with ribose and MTGase (MC-MTG/R). Protein cross-linking due to ε-(γ-glutamyl)lysine bonds and “Maillard cross-linking” were evidenced in the SDS-PAGE profiles of MC-C/R, MC-MTG/S and MC-MTG/R. Even though the microcapsules prepared with cross-linking treatments had significantly (P < 0.05) lower protein solubility as compared to that of the control, the results of fish oil release in pepsin solution at 37 °C indicated that the core release of all microcapsules prepared with ribose (MC-C/R and MC-MTG/R) was significantly (P < 0.05) lower than other microcapsules. During storage, microcapsules prepared with ribose had longer shelf life as compared to other microcapsules. This may be due to the release of antioxidative Maillard reaction products during heating and storage and a slower rate of gas permeability through the capsules.

Industrial relevance

The use of protein-based wall materials in the food industry for sensitive ingredients is limited because proteins are generally unstable with heating and damaged by organic solvents and the cross-linking agent is usually harmful. Therefore a novel method of combining two familiar cross-linking agents such as the microbial transglutaminase and ribose can convert SPI microcapsules into a stable form. The application of SPI in industry would be increased.     

A yeast gene encoding a putative RNA helicase of the “DEAD”-box family

An unknown open reading frame from Saccharomyces cerevisiae was identified and sequenced. The predicted amino acid sequence shows high homology to the DEAD-box family of proteins. Gene disruption revealed that the gene is not essential for yeast but necessary for normal cell growth.     

Microbial quality of condensation in fresh and ready-to-eat processing facilities

The objective was to determine the microbial risks associated with condensation in harvest, fabrication, and ready-to-eat (RTE) meat processing environments. A total of 2281 samples were collected before and during operation from areas of visible condensation, overhead pipes, and dripping pans in three plants each season during a one-year period. Significant interactions between season and plant type were observed for nearly all microorganisms, resulting in counts that were generally higher in the summer compared to other seasons. Aerobic plate counts ranged from non-detectable to 3.7 log cfu 100 mL^− 1 of condensation. Overall counts were so low that data had to be converted to results 100 mL^− 1. Coliforms and Enterococci were not detectable in most condensation samples. Yeast and mold averaged less than 3.0 log cfu 100 mL^− 1 in all samples. Listeria spp. or Salmonella were each detected in only two samples. Condensation, present in harvest, fabrication, and RTE meat processing areas does not appear to contain microbial loads that will contaminate the product.     

Removing τ‐fluvalinate residues from press‐extracted honey

Honey is obtained from the hives of European honeybees. Honeybees can be infested by Varroa parasitism, which affects honey production. The acaricide τ‐fluvalinate used in beehives to control Varroa mites, can leave its residues in honey, pollen and wax. A monitoring study was undertaken to determine the τ‐fluvalinate residues in honey samples taken from treated hives. The τ‐fluvalinate residues were determined by gas chromatography using a short, non‐polar packed column with electron capture detection. Analysis of 50 samples showed an average residue level of 15 µg kg⁻¹. The same samples were filtered through Whatman filter paper to separate the honey from residual suspended particles. The filtered honeys showed no acaricide residues above the detection limit of 3 µg kg ⁻¹, while the average residue level determined in the sediments was 392 µg kg ⁻¹. Thus the residues of τ‐fluvalinate in honey can be eliminated by separating the honey from residual suspended particles that contain acaricide residues. Copyright © 2003 Society of Chemical Industry     

Measurement of mimosine and its metabolites in biological materials

Recent results in both plant biochemistry and animal metabolism emphasise that, in any research on the nutritional applications of Leucaena leucocephala, measurement of mimosine should be accompanied by measurement of the degradation product 3-hydroxy-4(1H)-pyridone. This may reveal wide differences in the toxic load coming from the feed and in the animal metabolic response to it. The authors suggest that where mimosine analysis can only be performed by the traditional colorimetric method, it should be combined with paper chromatography to estimate ratios of mimosine and 3,4-DHP. However high performance liquid chromatography provides vastly improved methods for simultaneously and precisely analysing both compounds. Published methods are reviewed and a new ion exchange method is described which has been used for the rapid routine analysis of a large number of samples. The chromatographic properties and separation of 2,3-dihydroxypyridine, a recently discovered metabolite, and of 3-glucuronyl-4(1H)pyridone from the above compounds are also reported.     

Influence of salt content and processing time on sensory characteristics of cooked "lacón"

The influence of salt content and processing time on the sensory properties of cooked "lacón" were determined. "Lacón" is a traditional dry-cured and ripened meat product made in the north-west of Spain from the fore leg of the pig, following a similar process to that of dry-cured ham. Six batches of "lacón" were salted with different amounts of salt (LS (3 days of salting), MS (4 days of salting) and HS (5 days of salting)) and ripened during two times (56 and 84 days of dry-ripening). Cured odour in all batches studied, red colour and rancid odour in MS and HS batches, flavour intensity in MS batch and fat yellowness, rancid flavour and hardness in the HS batch were significantly different with respect to the time of processing. Appearance, odour, flavour and texture were not significantly affected by the salt content (P>0.05). However, the saltiness score showed significant differences with respect to the salt levels in all studied batches (56 and 84 days of process). The principal component analysis showed that physicochemical traits were the most important ones concerning the quality of dry-cured "lacón" and offered a good separation of the mean samples according to the dry ripening days and salt level.     

Impact of Microclimate on Fatty Acids and Volatile Terpenes in “Kerman” and “Golden Hills” Pistachio (Pistacia vera) Kernels

Pistachio is an economically important nut crop in California. Since temperature variations among geographical locations can influence biochemical processes during fruit development, it is of great relevance to understand the impact of growing area over the components that define the nutritional and sensory characteristics of pistachio nuts. Changes in moisture, fat content, fatty acid composition and volatile terpenes were studied during kernel development for “Kerman” and “Golden Hills” varieties in two different California Central Valley microclimates, Lost Hills and Parlier. Moisture content decreased from July to September for both cultivars at both locations. Kerman had a higher moisture content at both locations compared with Golden Hills. Harvest time affected fat content only for Kerman, where the values increased drastically from 21‐July to 4‐Aug, then remained constant. Golden Hills’ fat content remained constant during the period of the study. The main fatty acid in pistachio oil is oleic acid (46% to 59%), followed by linoleic acid (26% to 36%) and palmitic acid (11% to 16%). C16:0, C16:1, C18:2, and C18:3 decreased with harvest time, while C18:1 increased. α‐Pinene was the most concentrated volatile among the cultivars and locations. It decreased with harvest time for both cultivars at both locations, ranging from 105 to 2464 mg/kg. At harvest, Golden Hills and Kerman at Parlier both had higher concentrations of α‐pinene than the two cultivars at Lost Hills. Our results demonstrate that microclimate affects biosynthesis of fatty acids and terpenes in pistachio kernels, the main compounds responsible for pistachio nutritional and sensory characteristics.     

Potential Prophylactic Properties of Apple and Characterization of Potent Bioactive from cv. “Granny Smith” Displaying Strong Antimutagenicity in Models Including Human Lymphoblast TK6+/− Cell Line

Potential prophylactic attributes in terms of antimutagenicity, antioxidant, and radioprotective properties were evaluated for 8 common apple cultivars namely “Fuji,” “Golden Delicious,” “Granny Smith,” “Ambri Kashmiri,” “Kinnaur,” “Red Delicious,” “Royal Gala,” and “Shimla,” where cultivar based significant variation was observed. Cv. “Granny Smith” displayed significantly higher and broad spectrum antimutagenicity in Escherichia coli rpoB based rifampicin resistance (Rif^R) assay, whereas, “Ambri Kashmiri,” “Royal Gala,” and “Shimla” showed lower antimutagenicity. Cultivars “Ambri Kashmiri,” “Kinnaur,” and “Red Delicious” exhibited strong antioxidant activity than cv. “Granny Smith” as assayed by radical scavenging, reducing potential and radioprotective property assays. The antioxidant and radioprotective properties were found to be better correlated than antimutagenicity. Suppression of error‐prone DNA repair pathway (such as E. coli SOS response) was found to be one of the possible mechanisms contributing to its antimutagenicity. Phenolic extract of “Granny Smithˮ showing higher antimutagenicity was HPLC purified and the bioactive fraction (t_R 35.4 min) contributing maximally (∼80%) to the observed antimutagenicity was identified as procyanidin dimer (PD) by ESI‐MS/MS. The above observed antimutagenicity in bacterial assay system was well reproduced in Thymidine Kinase Mutation (TKM) assay performed using human lymphoblast cell line (TK6^+/−) cell line making the findings more prophylactically relevant.     

Scombroid poisoning. Isolation and identification of “saurine”

A number of samples of fish which were involved in allergy-like food poisoning incidents were examined for the presence of “saurine”, a toxin reported to be the causative agent in scombroid poisoning. Chromatograms of extracts developed in acidic solvents showed two distinct areas which possessed vagal stimulating activity with guinea pig ileum. Both these areas contained histamine and this suggests that “saurine” is a histamine salt.