Decontamination of fluid milk containing Bacillus spores using commercial household products

Although commercial sanitizers can inactivate bacterial spores in food processing environments, relatively little data exist as to the decontamination of products and surfaces by consumers using commercial household products. Should a large scale bioterrorism incident occur in which consumer food products were contaminated with a pathogenic sporeformer such as Bacillus anthracis, there may be a need to decontaminate these products before disposal as liquid or solid waste. Studies were conducted to test the efficacy of commercial household products for inactivating spores of Bacillus cereus (used as a surrogate for B. anthracis) in vitro and in fluid milk. Validation of the resistance of the B. cereus spores was confirmed with B. anthracis spores. Fifteen commercial products, designed as either disinfectants or sanitizers or as potential sanitizers, were purchased from retail markets. Products selected had one of the following active compounds: NaOCl, HCl, H2O2, acetic acid, quaternary ammonium compounds, ammonium hydroxide, citric acid, isopropanol, NaOH, or pine oil. Compounds were diluted in water (in vitro) or in 2% fat fluid milk, and spores were exposed for up to 6 h. Products containing hypochlorite were most effective against B. cereus spores. Products containing HCl or H2O2 also reduced significant numbers of spores but at a slower rate. The resistance of spores of surrogate B. cereus strains to chlorine-containing compounds was similar to that of B. anthracis spores. Therefore, several household products on the market may be used to decontaminate fluid milk or similar food products contaminated by spores of B. anthracis.     

亚损伤状态下枯草芽孢杆菌芽胞萌芽影响因素的研究

为了研究食品中营养要素对处于亚损伤状态枯草芽孢杆菌芽胞的影响,采用分批培养法,利用食品中存在的碳源、氮源、无机盐离子等分别诱导芽胞萌芽,采用正交实验研究了温度、p H、接种量、溶氧量对芽胞萌芽率的影响,分别在OD580下测定其光密度值,得到芽胞萌芽率。结果显示,麦芽糖、乳清蛋白是芽胞萌芽的最佳碳源、氮源;无机盐Mg SO4对芽胞萌芽产生显著的诱导作用。以麦芽糖（5 mg/m L）,Mg SO₄（5 mg/m L）,乳清蛋白（5 mg/m L）为基础培养基,芽胞的最佳生长条件为:接种量4%、p H7.0、溶氧量70 m L,37℃恒温振荡培养60 min,得芽胞萌芽率最大为15.27%。      

Migration of bisphenol-A diglycidyl ether (BADGE) and its reaction products in canned foods

Bisphenol-A diglycidyl ether (BADGE) is used as an additive or starting agent in coatings for cans. The presence of hydrochloric acid in the organosol (PVC-based) lacquers results in formation of chlorohydroxy compounds of BADGE. These compounds, as well as BADGE itself, are potential migrants into the preserved food and are of toxicological concern. In the present investigation the presence of BADGE and the chlorohydroxy compounds (BADGE.HCl and BADGE.2HCl) in various kinds of canned foods from 30 brands have been determined by HPLC with fluorescence detection. BADGE was found in levels up to 5.1mg/kg in the food and only in food from cans containing BADGE.HCl and BADGE.2HCl in the lacquers. BADGE was found both in fish in oil and in fish in tomato sauce, however, the highest amounts were found in the fatty foodstuffs. BADGE.HCl and BADGE.2HCl were found in concentrations up to 2.4mg/kg and 8.3mg/kg, respectively. Unlike BADGE, BADGE.2HCl was found in similar concentrations in fish in oil and in fish in tomato sauce. In aqueous and acidic foodstuffs BADGE readily hydrolyses into mono- and dihydrolysed products (BADGE.H₂O and BADGE.2H₂O). In this study BADGE.H₂O was not found in any food sample, whereas BADGE.2H₂O was found in levels up to 2.6mg/kg. The Scientific Committee for Food (SCF) of the European Commission has proposed that a limit of restriction of 1mg/kg food shall include BADGE itself and BADGE.H₂O, BADGE.HCl, BADGE.2HCl and BADGE.HCL.H₂O. The present results indicate that the migration of BADGE.HCl and BADGE.2HCl, compounds with almost no data on toxicity, implies a greater problem than BADGE.H₂O and BADGE.2H₂O.     

低温等离子体及防腐剂对解淀粉芽孢杆菌芽孢灭活效果的影响

为了研究低温等离子体及防腐剂对解淀粉芽孢杆菌（Bacillus amyloliquefaciens）芽孢杀死率的影响,分别采用不同质量浓度的单一和复合防腐剂加入到含有菌悬液的培养基中,采用不同功率与时间低温等离子体对菌体进行处理,考察不同质量浓度防腐剂及不同功率与时间低温等离子体对解淀粉芽孢杆菌芽孢致死率的影响。结果表明,单一防腐剂抑制效果由大到小顺序为脱氢乙酸钠＞乳酸链球菌素＞山梨酸钾,脱氢乙酸钠在质量浓度为4 mg/mL时,芽孢抑制率可达97%;脱氢乙酸钠∶乳酸链球菌素（1∶1）、脱氢乙酸钠∶山梨酸钾∶乳酸链球菌素（1∶2∶1）复合防腐剂抑制效果较好,质量浓度为0.5 mg/mL时芽孢抑制率可达90%以上;低温等离子体在相同功率下,时间越短,抑菌效果越好,最佳抑菌效果条件为300 W、50 s。     

Synergistic killing of spores of Bacillus subtilis by peracetic acid and alcohol

Synergistic sporicidal effects were observed when spores of Bacillus subtilis SA22 (NCA 72-52) were exposed to 0.08% (v/v) peracetic acid plus 9.9% (v/v) various primary alcohols. Synergistic sporicidal responses were also found when combinations or 0.04 or 0.08% (vlv) peracetic acid plus up to approximately 20% (v/v) ethanol were used. Higher concentrations of ethanol or peracetic acid did not yield further sporicidal action. Simultaneous use of ethanol and peracetic acid is a possible method of sterilization of aseptic packaging materials.     

我国罐头工业发展成就和21世纪展望(一)

<正> 我国罐头工业始于1906年,上海泰丰食品公司是我国第一家罐头食品厂。此后,在少数省市建立了一些作坊式罐头加工厂,从建国到1953年,全国只有20多家工厂。1954年开始,产品向原苏联及东欧国家出口,1962年转向西方国家出口。党的十一届三中全会以来,由于经济作物种植面积和单位面积产量大幅度增加,为罐头工业提供了丰裕的原料,罐头食品生产量和出口逐年增长,90年代罐头食品被确定为轻工业10个拳头产品之一。     

我国罐头工业发展成就和21世纪展望(二)

<正> 当前,我国罐头行业发展中存在的问题是全行业连续多年亏损,宏观失控,有些国有企业包袱沉重,经营不善,市场意识薄弱,资金不足,濒临倒闭,严重影响全行业的发展。另一方面,外贸体制改革后,没有完善的配套政策,小型罐头厂一哄而起,竞争无序,高价抢购劣质原料,低价竞销成品,造成出口市场混乱,产品质量不稳定,缺少新品种,不能适应国内外市场需要。此外,包装容器开启不方便,装璜不美观,名牌品牌太少,使国内消费     

Inactivation of Bacillus spores by the combination of moderate heat and low hydrostatic pressure in ketchup and potage

The combination effect of moderate heat and low hydrostatic pressure (MHP) on the reduction of Bacillus subtilis, Bacillus coagulans and Geobacillus stearothermophilus spores in food materials (potage and ketchup) was investigated. These bacterial spores were suspended in potage (pH 7), acidified potage (pH 4), neutralized ketchup (pH 7) and ketchup (pH 4). The suspensions were treated with and without pressure (100 MPa) and temperatures of 65-85 degrees C for 3 to 12 h. The bacterial spores were inactivated by 4-8 log cycles during MHP treatment in potage, acidified potage and ketchup, whereas the spores were highly resistant to long time heat treatment in potage and neutralized ketchup. The degrees of spore destruction were mostly dependent on pH and medium composition during MHP treatment. The inactivation effect in MHP treatment was higher at the pH 7 than at pH 4 both in ketchup and potage. The bacterial spores showed higher inactivation in potage than ketchup during MHP treatment.     

Pilot-scale crossflow-microfiltration and pasteurization to remove spores of Bacillus anthracis (Sterne) from milk

High-temperature, short-time pasteurization of milk is ineffective against spore-forming bacteria such as Bacillus anthracis (BA), but is lethal to its vegetative cells. Crossflow microfiltration (MF) using ceramic membranes with a pore size of 1.4 μm has been shown to reject most microorganisms from skim milk; and, in combination with pasteurization, has been shown to extend its shelf life. The objectives of this study were to evaluate MF for its efficiency in removing spores of the attenuated Sterne strain of BA from milk; to evaluate the combined efficiency of MF using a 0.8-μm ceramic membrane, followed by pasteurization (72°C, 18.6 s); and to monitor any residual BA in the permeates when stored at temperatures of 4, 10, and 25°C for up to 28 d. In each trial, 95 L of raw skim milk was inoculated with about 6.5 log₁₀ BA spores/mL of milk. It was then microfiltered in total recycle mode at 50°C using ceramic membranes with pore sizes of either 0.8 μm or 1.4 μm, at crossflow velocity of 6.2 m/s and transmembrane pressure of 127.6 kPa, conditions selected to exploit the selectivity of the membrane. Microfiltration using the 0.8-μm membrane removed 5.91 ± 0.05 log₁₀ BA spores/mL of milk and the 1.4-μm membrane removed 4.50 ± 0.35 log₁₀ BA spores/mL of milk. The 0.8-μm membrane showed efficient removal of the native microflora and both membranes showed near complete transmission of the casein proteins. Spore germination was evident in the permeates obtained at 10, 30, and 120 min of MF time (0.8-μm membrane) but when stored at 4 or 10°C, spore levels were decreased to below detection levels (≤0.3 log₁₀ spores/mL) by d 7 or 3 of storage, respectively. Permeates stored at 25°C showed coagulation and were not evaluated further. Pasteurization of the permeate samples immediately after MF resulted in additional spore germination that was related to the length of MF time. Pasteurized permeates obtained at 10 min of MF and stored at 4 or 10°C showed no growth of BA by d 7 and 3, respectively. Pasteurization of permeates obtained at 30 and 120 min of MF resulted in spore germination of up to 2.42 log₁₀ BA spores/mL. Spore levels decreased over the length of the storage period at 4 or 10°C for the samples obtained at 30 min of MF but not for the samples obtained at 120 min of MF. This study confirms that MF using a 0.8-μm membrane before high-temperature, short-time pasteurization may improve the safety and quality of the fluid milk supply; however, the duration of MF should be limited to prevent spore germination following pasteurization.     

Differentiation of Tetragenococcus populations occurring in products and manufacturing processes of puffer fish ovaries fermented with rice-bran

Tetragenococcus strains isolated from the manufacturing process of Japanese puffer fish ovaries fermented with rice-bran were characterized and differentiated phenotypically and genotypically. A total of 413 Tetragenococcus isolates were evaluated. On the basis of five representative substrates, the isolates were grouped into seven groups. An RFLP (restriction fragment length polymorphisms) analysis of the 16S rRNA gene of representative strains of major groups revealed that they could be grouped into two groups: one was identified as the most prominent halophilic lactic acid coccus, Tetragenococcus halophilus, and the other as T. muriaticus, which has recently been added to the genus Tetragenococcus as a new species. Physiologically, the major differences between the two groups were found in the ability to grow in medium not supplemented with NaCl and the fermentation of L-arabinose, sucrose and D-mannitol, and several other carbohydrates.     

A study on the effects of high pressure and heat on Bacillus subtilis spores at low pH

Bacillus subtilis spore suspensions were subjected to pressure treatments at 100 and 600 MPa at 40 degrees C and over a pH range from 3 to 8. Inactivation of spores under these conditions was maximally 80% and was not increased at low pH. However, higher levels of inactivation were obtained when spores were first pressure treated at neutral pH and then exposed for 1 h to low pH. This large difference in inactivation could be explained by the finding that pressure-induced spore germination, which is known to occur at neutral pH, was inhibited at low pH (< 5). Pressure treatment at low pH made spores more sensitive to heat inactivation, suggesting that demineralized H-spores had been formed. Changes in spore core hydration and pH upon exposure of spores at low pH were studied in a more direct way using green fluorescent protein expressed in recombinant B. subtilis as a reporter protein, and it was confirmed that pressure and heat increase spore permeability for protons. Based on these results, the potential of low temperature, high pressure processes for spore inactivation in acid products is discussed.     

Modelling the influence of pH and organic acid types on thermal inactivation of Bacillus cereus spores

A model is proposed to describe the influence pH on the heat resistance of Bacillus cereus spores. In addition to the conventional z value, the effect of pH on the thermal resistance of spores is characterised by a z(pH) value (z(pH) is the distance of pH from a reference pH*, which leads to a 10-fold reduction of D value). The type of organic acid used for acidifying the heating medium, influences the z(pH) value. For nine organic acids, a linear relationship between the calculated z(pH) value and its lower acid pKa is observed. This relationship showed that the acid form (dissociated or undissociated) modifies the thermal spore resistance in addition to the H+ ion. The influence of acetic acid concentration on the D value at pH 7 shows the protective effect of the dissociated acid form on the heat resistance of spores. The acid concentration in the medium modified the heat resistance of spore and the z(pH) value.     

Comparative egg morphology of silvanid and laemophloeid beetles (Coleoptera) occurring in stored products

Eggs of eight pest species of Silvanidae and Laemophloeidae commonly occurring in stored products (grain and flour etc.) in Europe are described. Comparisons include overall appearance, size, surface sculpturing and changes in external appearance during development of the embryo. Morphological details are illustrated with scanning electron micrographs. A key for distinguishing eggs of these pests at generic level is provided. The study did not reveal structural characters of value for distinguishing eggs at the species level and thus the development of specific immunological or molecular identification methods is suggested.     

Determination of Bisphenol A diglycidyl ether (BADGE) and its hydrolysis products in canned oily foods from the Austrian market

 Bisphenol A diglycidyl ether (BADGE) is determined in canned oily foods from Austria using a new simplified HPLC method. Samples are extracted with pentane, back extracted with methanol, and finally dissolved in the mobile phase (cyclohexane/tert–butyl methyl ether). Separation is performed on a normal-phase HPLC column using fluorescence detection. Verification of the BADGE-containing peak is carried out by using off-line GC-MS. Additionally, the synthesis and determination of BADGE hydrolysis products, Bisphenol A bis(2,3-dihydroxypropyl) ether (BADGE.2H₂O) and Bisphenol A glycidyl (2,3-dihydroxypropyl) ether (BADGE.H₂O) are presented. From 67 analyzed cans, containing various fatty meat or fish products, 16% were above the maximum quantity of 1 mg/kg tolerated by the European Community, 45% were in the range between 0.1–1 mg/kg, 24% between 0.02 and 0.1 mg/kg, and in 15% the BADGE concentrations were below the detection limit of 0.02 mg/kg. The hydrolysis product BADGE.H₂O was not detected in any sample, whereas BADGE.2H₂O was found in some samples up to a concentration of 0.5 mg/kg. Received: 11 May 1998 / Revised version: 1 July 1998     

Protein,amino acid and fatty acid contents in raw and canned sea urchin (Paracentrotus lividus) harvested in Galicia (NW Spain)

Moisture, protein, amino acid and fatty acid contents of raw and canned sea urchin (Paracentrotus lividus) gonads were determined. Sea urchin showed a high moisture content (73%) and a high level of proteins (56% dry matter). The canning process, evaluated at 112 °C for 50 min, did not lead to significant changes in protein, amino acid and fatty acid contents relative to the raw sample. © 2000 Society of Chemical Industry     

Determination of a process time for a new product: canned low acid artichoke hearts

In order to obtain a process time for canned low acid artichoke hearts, the heat resistance of Clostridium sporogenes PA 3679 in phosphate buffer (pH 7) and in artichoke puree (pH 5.2) was determined in the range of 100–118°C. D _T values in artichoke puree were determined by the most probable number and plate count methods. D _121°C values were deduced by extrapolation of the curves. An F 8.3/121 (see nomenclature section) target value of 1.8 min, equivalent to an F ₀= 2.5 min, was established considering a D _121°C value of 0.36 min for artichoke puree. The cold point for canned artichoke hearts in 1/2 kg (71.5x117 mm) cans was determined, a set of heat penetration and cooling curves were obtained and the values of the parameters ' j ' and ' f ' were found. A process time was deduced, 21.5 and 23 min of heating at 121°C, following the methods of Patashnik (1954) and Hayakawa (1970, 1974) respectively, in order to reach the F ₀ target of 2.5 min for this new canned food. This process was adequate, as the inoculated experimental pack test showed no altered cans out of 50 inoculated after 21.5 min of heating at 121°C.     

High-pressure inactivation of Bacillus cereus spores in the presence of argon

We investigated the high-pressure inactivation of Bacillus cereus spores in water containing argon. At the pressure of 600 MPa, addition of argon accelerated the inactivation of spores at 20 degrees C, but had no effect on the inactivation at 40 degrees C. The influence of added argon on inactivation of the spores was marked under conditions with a strong 'water ordering' effect. The pressure resistance of B. cereus spores was thus shown to be affected by 'water ordering'.     

Factors affecting the heat resistance of Bacillus stearothermophilus spores

Summary. Maximum colony counts of unheated and heated spores of Bacillus stearothermophilus were obtained after incubation at 50-65°C and 45-50°C, respectively. the composition of the plating medium was found to have a marked effect upon recovery of unheated and heated spores. the effects of diluent and incubation time on recovery have also been investigated.     

Antimicrobial effect of a combination of herb extract and organic acid against Bacillus subtilis spores

Food Science and Biotechnology - The sporicidal activities of the herbs were investigated to screen for novel antimicrobial substances against Bacillus subtilis spores. The bacterial inactivation...