Survival of Salmonella in peanut butter and peanut butter spread

In 1996, the first documented outbreak of salmonellosis associated with the consumption of peanut butter was reported. This study was undertaken to determine survival characteristics of high (5.68 log10 cfu g(-1)) and low (1.51 log10 cfu g(-1)) inocula of a five-serotype mixture of Salmonella in five commercial peanut butters and two commercial peanut butter spreads. Populations in samples inoculated with 5.68 log10 cfu g(-1) and stored for 24 weeks at 21 or 5 degrees C decreased 4.14-4.50 log10 cfu g(-1) and 2.86-4.28 log10 cfu g(-1), respectively, depending on the formulation. The order of retention of viability was: peanut butter spreads > traditional (regular) and reduced sugar, low-sodium peanut butters > natural peanut butter. Differences in rates of inactivation are attributed to variation in product composition as well as size and stability of water droplets in the colloidal matrix, which may influence nutrient availability. With the exception of natural peanut butter, products initially inoculated with 1.51 log10 cfu of Salmonella g(-1) (32 cfu g(-1)) were positive for the pathogen after storage for 24 weeks at 5 degrees C. At 21 degrees C, however, with the exception of one peanut butter spread, all products were negative for Salmonella after storage for 24 weeks. Post-process contamination of peanut butter and spreads with Salmonella may to result in survival in these products for the duration of their shelf life at 5 degrees C and possibly 21 degrees C, depending on the formulation.     

Wistar Rats and Premature Infants

The molar proportions of essential amino acids in the fasting plasma of Wistar rats were shown to have utility in: (i) Determining the limiting essential amino acid for peanut butter and whole egg protein; (ii) Ranking in proper order peanut butter protein supplemented with two levels of lysine and whole egg protein according to their Biologic value and net protein utilization.

The molar proportions of the essential amino acids in the fasting plasma of adult humans were shown to have utility in ranking five rations according to their Biol.ogic value and net protein utilization by premature infants.     

4种饵料对小火蚁工蚁的诱集效果比较

小火蚁Wasmannia auropunctata Roger被世界自然保护联盟（IUCN）列为最具危害性的100种入侵物种之一。2022年1月份,小火蚁首次被发现入侵中国大陆,开发小火蚁的监测技术对于摸清该种入侵蚂蚁的发生程度与分布范围有重要意义。本文测定了火腿肠、花生酱、花生油和蜂蜜等4种饵料对小火蚁的诱集效果,并对不同生境小火蚁数量进行了调查。室内试验中火腿肠诱集效果最好,花生酱和花生油次之,蜂蜜最差。在野外试验中,花生酱和火腿肠的诱集效果最佳,放置30 min的诱集数量与60 min时无显著差异,并且饵料摆放瓶口处能诱集到更多工蚁,上午和下午更适宜进行诱集试验。利用花生酱进行野外调查发现小火蚁在山腰、山脚、屋内、田埂和路边等生境中均有分布。以上结果为进一步开展小火蚁疫情的调查提供了参考。     

两种赋形剂载体中姜黄素干预慢性应激大鼠抑郁样行为和肌肉炎性反应的作用研究

目的:从抑郁样行为和肌肉炎性反应角度,研究姜黄素在由可可脂和花生油两种赋形剂载体时,对慢性应激大鼠的干预作用。方法:分别制备以可可脂和花生油为赋形剂的姜黄素制剂,使用SD雄性大鼠50只随机分为空白对照组、模型对照组、姜黄素可可脂组、姜黄素花生油组、阳性对照组,除空白对照组外,各组均采用束缚、噪音声刺激、冰水浴刺激、夹尾疼痛刺激等方法持续6周建立慢性应激大鼠模型,在维持模型刺激条件的基础上分别给予各种设计药物,连续用药7 d后在考察各组模型动物悬尾挣扎时间、机械痛阈、糖水偏好的行为学变化,然后使用Elisa试剂盒法检测各组大鼠脑中5五羟色胺(5-HT)和多巴胺(DA)含量,制作大鼠咬肌组织的HE染色切片观察肌肉病理变化,检测咬肌组织中高迁移率族蛋白B1(HMGB-1)、白介素1β(IL-1β)、白介素6(IL-6)、肿瘤坏死因子α(TNF-α)水平。结果:与模型组相比,两种姜黄素均能显著降低应激大鼠抑郁样行为,改善脑内5-HT和DA含量的作用较阳性对照组弱,咬肌病理切片中两种姜黄素组可明显减少应激大鼠咬肌组织血管周围的炎性反应。两种姜黄素能显著降低咬肌组织中的IL-1β、IL-6、TNF-α水平(P<0.05),其中姜黄素可可脂组作用最明显。结论:两种姜黄素制剂对抗慢性应激大鼠的抑郁样症状均有治疗作用,均可降低咬肌中炎性因子HMGB-1、IL-1β、IL-6、TNF-α水平,其中可可脂作为赋形剂时作用较显著,在姜黄素的抗抑郁制剂研究中具有较好的开发潜力。     

Survey of aflatoxin-producing fungi in certain fermented foods and beverages in Thailand

Aflatoxin-producing fungi were found in fermented foods and beverages: fermented rice (kaomak), soybean sauce (taotjo), peanut butter, soy sauce (shoyu), Thai red and white wine, and rice sugar wine. These foods were extracted directly and tested for aflatoxins by thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC).Four strains of aflatoxin-producing fungi were isolated from peanut butter, taotjo, and shoyu. Direct extracts of 10% of the peanut butters tested and 5% of the kaomak tested contained large amounts of aflatoxins. The HPLC procedure used in this experiment utilized chloroform-ethyl acetate (31)     

The effect of traditional African food mixtures on growth, pH and extracellular polysaccharide production by mutans streptococci in vitro

Four, traditional African food mixtures (maize plus milk and sugar, maize plus gravy, samp plus beans, brown bread plus margarine and peanut butter) were evaluated for their ability to sustain the growth of mutans streptococci in batch culture. A synthetic complex medium, brain heart infusion with 3% sucrose was used as an experimental control. Six NCTC laboratory reference strains and five clinical isolates collected from the plaque of children were investigated. The doubling time of bacterial strains was prolonged in maize plus gravy (2.5-6.0 h) and samp plus beans (1.3-9.9h), and the number of cell divisions was low, compared with bread plus margarine plus peanut butter (0.7-5.1h). The least amount of acid was produced in maize plus milk plus sugar (3.92+/-8.15 mmole/mL), and the average pH during the fermentation of maize plus milk plus sugar, maize plus gravy and samp plus beans did not drop below the critical point for enamel demineralisation, pH 5.7. Bacterial growth in samp plus beans produced a small quantity of lactic acid (0.46+/-1.10 mmole/mL) compared to bread plus margarine and peanut butter (2.64+/-3.30 mmole/mL) and BHI plus 3% sucrose (12.23+/-10.72 mmole/mL). Extracellular polysaccharide (ECP) produced was lowest in maize plus milk and sugar (0.22+/-0.33 mg/mL), compared with the remaining food mixtures (0.47-1.75 mg/mL). Statistical analysis showed that the influence of the mixed-foods on doubling time (F=3.01, P=0.03), pH (F=14.41, P<0.0001) and ECP (F=135.32, P<0.0001) was greater than the significant variance found between mutans streptococci strains. Results suggest that the level of mutans streptococci activity in samp plus beans, maize plus milk and sugar and maize plus gravy contributes little towards the formation of dental caries, and that significant differences exist between mutans streptococci laboratory reference and clinical strains in response to traditional African food mixtures.     

A note on the screening of dried shrimps, shrimp paste and raw groundnut kernels for aflatoxin-producing Aspergillus flavus

All of 33 samples of dried shrimps, shrimp paste, peanut butter and raw groundnut kernels were contaminated with fungi. Aspergillus and Penicillium spp. were the predominant types in dried shrimps and raw groundnut kernels but no Aspergillus spp. were present in peanut butter or shrimp paste samples. Among 81 Aspergillus isolates obtained from dried shrimps and raw groundnut kernels, 10 were A. flavus/A. parasiticus, of which five were potential aflatoxin-producing A. flavus strains. No aflatoxins were detected in the food samples although some were visibly mouldy and some had high mould counts. The occurrence of aflatoxin-producing strains of A. flavus in dried shrimps and raw groundnut kernels warrants further investigation of these foods and their products as potentially significant sources of aflatoxins.     

Aflatoxins in peanut butter in Khartoum State,Sudan

Forty-three peanut butter samples from Khartoum State, Sudan, were analyzed for aflatoxins (AFs, AFB₁ + AFB₂ + AFG₁ + AFG₂) using high performance liquid chromatography (HPLC) with fluorescence detection after extraction with methanol:water (8:1, v/v) and clean-up using chloroform. All samples were contaminated with AFs, with total AF levels ranging between 26.7 and 853 μg/kg, and a mean total AF level of 287 ± 200.5 μg/kg. The highest concentrations were found for AFB₁, (28 positive samples, maximum 534 μg/kg), while AFG₁ was most frequently detected (43 positive samples, maximum 401 μg/kg). AFB₂ (42 positive samples, maximum 3.2 μg/kg) and AFG₂ (4 positive samples, maximum 30 μg/kg) were also present in these samples. The mean AF contamination levels found in this study exceeded by far all international regulations concerning maximum levels for this group of toxins. From the data, it is concluded that the levels of AF contamination in peanut butter from the Kartoum area are quite alarming, and may pose serious health hazards to consumers. Therefore, an intervention strategy to manage AF in peanut butter is urgently needed.     

The potential of an insect pheromone lure,Z‐7‐dodecen‐1‐yl acetate,compared with peanut butter to attract laboratory and wild rats and mice

Abstract

We compared the attractiveness to rats and mice of two lures, the pheromone Z‐7‐dodecen‐1 ‐y 1 acetate and peanut butter. In the first part of the study, laboratory‐bred rats and mice were placed in a Y‐maze. Each arm of the maze offered their normal food, plus either the pheromone or 5% ethanol as a control. There were no significant differences, by species or sex, in the number of visits or the amount of time spent in each arm. The male mice took significantly less time, however, to enter the control arm of the maze than the pheromone arm. In addition, female mice were less active during the first 5 min of the Y‐maze study than during the 5 min familiarisation period, suggesting a repellent effect of the pheromone lure. In the second part of the study, tracking tunnels were placed out in the field and baited with one of three lures—the pheromone, peanut butter or a 5% ethanol control. There was no significant difference in the number of visits by mice to tunnels containing the three lures, but rats made more visits to the tunnels containing peanut butter in the “Test” stage than in the “Neo” stage. The wild rats and mice were found not to be neophobic, suggesting the standard 3‐week familiarisation period is not necessary.     

The Role of Pigmentation, Ultraviolet Radiation Tolerance, and Leaf Colonization Strategies in the Epiphytic Survival of Phyllosphere Bacteria

Phenotypic mechanisms that enhance bacterial UVR survival typically include pigmentation and DNA repair mechanisms which provide protection from UVA and UVB wavelengths, respectively. In this study, we examined the contribution of pigmentation to field survival in Clavibacter michiganensis and evaluated differences in population dynamics and leaf colonization strategies. Two C. michiganensis pigment-deficient mutants were significantly reduced in UVA radiation survival in vitro; one of these mutants also exhibited reduced field populations on peanut when compared to the wild-type strain over the course of replicate 25-day experiments. The UVR-tolerant C. michiganensis strains G7.1 and G11.1 maintained larger epiphytic field populations on peanut compared to the UVR-sensitive C. michiganensis T5.1. Epiphytic field populations of C. michiganensis utilized the strategy of solar UVR avoidance during leaf colonization resulting in increased strain survival on leaves after UVC irradiation. These results further demonstrate the importance of UVR tolerance in the ability of bacterial strains to maintain population size in the phyllosphere. However, an examination of several bacterial species from the peanut phyllosphere and a collection of environmental Pseudomonas spp. revealed that sensitivity to UVA and UVC radiation was correlated in some but not all of these bacteria. These results underscore a need to further understand the biological effects of different solar wavelength groups on microbial ecology.     

几种饵料对红火蚁觅食的引诱作用

在荒地类型生境中测定花生酱、猫饲料、狗饲料、花生油、面包及蜂蜜等几种常见饵料对红火蚁的引诱作用。结果表明:面包、狗饲料、猫饲料和花生酱对红火蚁引诱力较强,花生油次之,蜂蜜最低;选择性试验结果表明红火蚁对供试的几种饵料无明显选择性。     

A note on the screening of dried shrimps, shrimp paste and raw groundnut kernels for aflatoxin-producing Aspergillus flavus

S im , T.S., T eo , T heresa & S im , T.F. 1985. A note on the screening of dried shrimps, shrimp paste and raw groundnut kernels for aflatoxin-producing Aspergillus flavus. Journal of Applied Bacteriology 59 , 29–34.
All of 33 samples of dried shrimps, shrimp paste, peanut butter and raw groundnut kernels were contaminated with fungi. Aspergillus and Penicillium spp. were the predominant types in dried shrimps and raw groundnut kernels but no Aspergillus spp. were present in peanut butter or shrimp paste samples. Among 81 Aspergillus isolates obtained from dried shrimps and raw groundnut kernels, 10 were A. flavus/ A. parasiticus , of which five were potential aflatoxin-producing A. flavus strains. No aflatoxins were detected in the food samples although some were visibly mouldy and some had high mould counts. The occurrence of aflatoxin-producing strains of A. flavus in dried shrimps and raw groundnut kernels warrants further investigation of these foods and their products as potentially significant sources of aflatoxins.     

A survey of aflatoxin B<Subscript>1</Subscript> and total aflatoxin contamination in baby food,peanut and corn products sold at retail in Indonesia analysed by ELISA and HPLC

Aflatoxin contamination has been well known as a world-wide health-threatening problem in tropical countries including Indonesia. This research was undertaken to determine the degree of aflatoxin contamination in different Indonesian foodstuffs. A preliminary survey was carried out to evaluate the level of total aflatoxin (AfT) and aflatoxin B₁ (AfB₁) contamination of baby foods, peanut products, and corn products, which were purchased from traditional markets and supermarkets in Indonesia during the year 2001-2002. Eighty two peanut products, 12 baby foods products, and 11 corn products from different brands were analysed for AfT and AfB₁ using the Enzyme-Linked Immunosorbent Assay (ELISA) method. The results indicate that, of the brands analysed, 35% of the peanut products were contaminated with aflatoxins at various levels (range 5 to 870 μg/kg). Peanut-chilli sauces had the highest percentage of AfT contamination 9/12 (75%), which was followed by traditional snacks 5/11 (45%), peanut butter 4/11 (40%), flour egg coated peanut 6/16 (37%), and peanut cake 3/10 (30%). Fried peanuts and roasted peanut were found to contain aflatoxin at relatively lower percentages of 9% and 8%, respectively. From the 12 analysed baby food samples, on the other hand, no sample was found to be contaminated with aflatoxins. Two of 11 samples (18%) of corn based products were contaminated with AfT, ranging between 5.8 and 12.4 μg/kg. Additionally, 30 selected samples in different concentration ranges were further analysed to verify the correlation between ELISA and HPLC techniques and results were compared.     

Increased Water Activity Reduces the Thermal Resistance of Salmonella enterica in Peanut Butter

Increased water activity in peanut butter significantly (P < 0.05) reduced the heat resistance of desiccation-stressed Salmonella enterica serotypes treated at 90°C. The difference in thermal resistance was less notable when strains were treated at 126°C. Using scanning electron microscopy, we observed minor morphological changes of S. enterica cells resulting from desiccation and rehydration processes in peanut oil.     

Assessment of the Sensitizing Potential of Processed Peanut Proteins in Brown Norway Rats: Roasting Does Not Enhance Allergenicity

Background

IgE-binding of process-modified foods or proteins is the most common method for examination of how food processing affects allergenicity of food allergens. How processing affects sensitization capacity is generally studied by administration of purified food proteins or food extracts and not allergens present in their natural food matrix.

Objectives

The aim was to investigate if thermal processing increases sensitization potential of whole peanuts via the oral route. In parallel, the effect of heating on sensitization potential of the major peanut allergen Ara h 1 was assessed via the intraperitoneal route.

Methods

Sensitization potential of processed peanut products and Ara h 1 was examined in Brown Norway (BN) rats by oral administration of blanched or oil-roasted peanuts or peanut butter or by intraperitoneal immunization of purified native (N-), heated (H-) or heat glycated (G-)Ara h 1. Levels of specific IgG and IgE were determined by ELISA and IgE functionality was examined by rat basophilic leukemia (RBL) cell assay.

Results

In rats dosed orally, roasted peanuts induced significant higher levels of specific IgE to NAra h 1 and 2 than blanched peanuts or peanut butter but with the lowest level of RBL degranulation. However, extract from roasted peanuts was found to be a superior elicitor of RBL degranulation. Process-modified Ara h 1 had similar sensitizing capacity as NAra h 1 but specific IgE reacted more readily with process-modified Ara h 1 than with native.

Conclusions

Peanut products induce functional specific IgE when dosed orally to BN rats. Roasted peanuts do not have a higher sensitizing capacity than blanched peanuts. In spite of this, extract from roasted peanuts is a superior elicitor of RBL cell degranulation irrespectively of the peanut product used for sensitization. The results also suggest that new epitopes are formed or disclosed by heating Ara h 1 without glucose.     

Effect of solar UV-B radiation on a phyllosphere bacterial community.

The effect of solar UV-B radiation on the population dynamics and composition of the culturable bacterial community from peanut (Arachis hypogeae L.) was examined in field studies using plants grown under UV-B-transmitting (UV-B+) or UV-B-excluding (UV-B-) plastic filters. Our data demonstrate that solar UV-B selection alters phyllosphere bacterial community composition and that UV tolerance is a prevalent phenotype late in the season. The total bacterial population size was not affected by either UV-B treatment. However, isolates from the UV-B+ plots (n = 368) were significantly more UV tolerant than those from the UV-B- (n = 363) plots. UV sensitivity was determined as the minimal inhibitory dose of UV that resulted in an inhibition of growth compared to the growth of a nonirradiated control. The difference in minimal inhibitory doses among bacterial isolates from UV-B+ and UV-B- treatments was mainly partitioned among nonpigmented isolates, with pigmented isolates as a group being characterized as UV tolerant. A large increase in UV tolerance was observed within isolate groups collected late (89 and 96 days after planting) in the season. Identification of 200 late-season isolates indicated that the predominant UV-tolerant members of this group were Bacillus coagulans, Clavibacter michiganensis, and Curtobacterium flaccumfaciens. We selected C. michiganensis as a model UV-tolerant epiphyte to study if cell survival on UV-irradiated peanut leaves was increased relative to UV survival in vitro. The results showed an enhancement in the survival of C. michiganensis G7.1, especially following high UV-C doses (300 and 375 J m(-2)), that was evident between 24 and 96 h after inoculation. A dramatic increase in the in planta/in vitro survival ratio was observed over the entire 96-h experiment period for C. michiganensis T5.1.     

Taking the bait: The influence of attractants and microhabitat on detections of fauna by remote‐sensing cameras

Autonomously triggered cameras are a common wildlife survey technique. The use of attractants and surrounding microhabitats is likely to influence detection probabilities and survey outcomes; however, few studies consider these factors. We compared three attractants (peanut butter‐based, tuna‐based and a control) in a Latin square design through a coastal shrubland with high microhabitat variability at Cape Otway, Victoria, Australia (38º50?S, 143º30?E). Deployments involved 36 cameras for four days in each of five years. The percentage cover of each vegetation structural type (low [no or sparse cover], moderate [grass] or high [shrubs]) within 20 m of each camera was calculated and reduced to a single variable using PCA. Dynamic occupancy modelling, with lure type and vegetation structure as covariates of detection probability, found that peanut butter attracted the greatest diversity of species (24 of 35 species, 69%) and yielded the greatest number of detections (50% of 319) when compared with tuna oil (66% and 24%, respectively) and the control (43% and 26%, respectively). Peanut butter attracted more Macropodidae (wallabies) and Muridae (rats and mice); however, vegetation structural variables were the greatest influence on Corvidae/Artamidae (raven/currawong) detections with higher detectability in more open areas. Vegetation structure also influenced Muridae detections. This study reinforces the critical choice of appropriate attractants and camera placement when investigating vertebrate groups and highlights the role of microhabitat in the detection of small mammals and birds. We suggest future large‐scale camera surveys consider different bait types and microhabitats in their designs, to control for any biases and enable future advice on ‘optimal’ methods.     

Effect of Fat Sources on Satiety

Objective: There are inconsistent reports on the satiety value of different fatty acids. This study compared the appetitive effects of two fat sources rich in monounsaturated fatty acids (peanut oil and canola oil) with a source rich in saturated fatty acids (butter). Research Methods and Procedures: After an overnight fast, lean participants completed a questionnaire eliciting information about hunger, fullness, desire to eat, and prospective consumption. They then consumed one of the preloads (muffins containing 40 g of each fat source or no fat) and 150 mL of water within 15 minutes. Questionnaires were completed again 30, 60, and 120 minutes after preload ingestion. Participants kept dietary records during the subsequent 24 hours. Results: Canola and peanut oil muffins resulted in higher fullness, and butter, canola, and peanut oil muffins resulted in lower hunger ratings 30, 60, and 120 minutes after preload ingestion compared with the fat‐free preload. No differences were observed among the fat‐containing loads. Although energy intake 24 hours after consumption of the preloads was also comparable on days the three fat‐containing loads were consumed, energy consumption after each study session was higher when the fat‐free muffins were provided. However, total energy intake, including the calories provided by the preloads, was similar across treatments. Discussion: These data do not support a differential satiety effect of fat sources rich in monounsaturated fatty acids relative to one rich in saturated fatty acids.     

Risk Assessment of Some PCDDs,PCDFs, Dioxin-Like PCBs,and PCBs in Contaminated Dairy Products: An Egyptian Pilot Case Study

Samples of butter, cream, and white cheese were collected from the city of Ismailia, Egypt, and analyzed for polychloro dibenzo-p-dioxins, pentachloro dibenzo-p-furans, and dioxin-like polychlorinated biphenyl, PCBs. Butter samples had the highest mean content of PCDD/F and dioxin-like PCBs. Butter samples were the most contaminated samples in all dairy products analyzed in this study, whereas white cheese samples were the least contaminated. The spectrum of congeners detected in butter and cream were similar, with all congeners at detectable levels, whereas the spectrum of congeners detected in white cheese differed, with some congeners, namely 1,2,3,4,7,8-Hexa CDD, 1,2,3,4,6,7,8-Hepta CDD, and 1,2,3,7,8,9-Hexa CDD below WHO TE toxicity levels. 1,2,3,7,7-PeCDD, with its high concentration, was the principal contributor to the TEQ intake in both cream and butter samples. Similarly, the high concentration of 2,3,4,7,8-PeCDF in cream, butter, and white cheese samples was the main factor contributing to their TEQ intake. Estimated intakes of PCDDs/Fs were 129.2, 115.8, and 51.25 pg WHO-TEQ/day for butter, cream, and white cheese, respectively. Taking into account the sum of PCDDs/Fs and dioxin-like PCBs, estimated intakes were, 171.7, 155.8, and 68 pg WHO-TEQ/day, for butter, cream, and white cheese, respectively. Assuming an average bodyweight of 60 kg (WHO-TEQ/kg), these levels correspond to bodyweight-normalized intake levels of .15, 2.92 and 0.95 pg WHO-TEQ/kg/day.