Packs Of Milk Research Articles

An electrochemical sensor for detection of trace-level endocrine disruptor bisphenol A using Mo2Ti2AlC3 MAX phase/MWCNT composite modified electrode

Bisphenol A (BPA) is an industrially preferred material for the production of plastic and polycarbonate as well as a used material for the interior of food and beverage cans. In this study, synthesis and electrochemical sensor application of Mo2Ti2AlC3/MWCNT (multi-walled carbon nanotube) nanocomposite for BPA sensing was evaluated. Mo2Ti2AlC3 was used as MAX phase material in the design of the sensor, and MWCNT was preferred to increase conductivity and sensitivity. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to determine Mo2Ti2AlC3/MWCNT nanocomposite's electrochemical sensor performances which had LOD of 2.7 nM and LOQ of 8.91 nM in the linear working range of 0.01–8.50 μM calculated from DPV. The composite showed a single oxidation step against BPA which is diffusion-controlled and irreversible. The sensor was successfully applied for the determination of BPA in milk pack, plastic bottle, and can with recoveries ranging from 95.67% to 100.60%. In addition, sensor performance was examined through selectivity, repeatability, and reusability studies. HPLC as a standard determination method was carried out for accuracy of the voltammetric determination method in the real samples. The developed sensor could be applied to different areas from industry quality control to clinical analysis for the detection of BPA.

Study on Detection of Adulteration Components in Packed Milk

Milk is a basic source of human diets, which contain essential materials such as carbohydrates, protein, lipids, minerals, vitamins and essential amino acids. In order to keep milk temporarily fresh, some unethical activities are usually adapted to prevent the financial losses due to the spoilage of milk during its transportation and sale. The aim of study is to identifying the adulterants presents in the samples and compare them with the standard products. The method used for the detection of neutralizers in milk is rosalic acid and forthe detection of formalin there was used Hehner’s Test in this study. The study had done on seven type of packed milk (MILK PACK NESTLE, MILK PACK PLUS, QUDRAT, TARANG, TAZA, EVERY DAY and KHATIZ). Finally the result showed, neutralizer which are using for the neutralizing of acidity in milk were negative in mentioned samples, but formalin which is used for the extending of milk shelf life was positive in MILK PACK NESTLE and TAZA PACKED MILK samples. From total 42 samples, we detected adulteration of formalin in 12 (28-30%) samples. We are advising to Society for the rejections of MILK PACK NESTLE and TAZA PACKED MILK as use, and related administrations’ must control the above packed milk imports.

Prevalence and Antimicrobial Resistance of Bacillus cereus in Milk and Dairy Products

Objective: To investigate the prevalence of Bacillus cereus in milk and dairy products along with detection of its antibiotic sensitivity. Design: Descriptive study. Samples: One hundred and fifty samples of market milk, ultra high temperature milk packs (UHT), condensed milk, Milk powder, Damietta cheese, Kariesh cheese and Ras cheese. Procedures: Samples were examined for isolation and identification of Bacillus spp. via direct and indirect isolation, molecular examination and antimicrobial resistance. Further molecular examination was carried out in 46 isolates to detect hblA, hblC, hblD, nheA, nheB and nheC genes Results: The prevalence of B. cereus by direct isolation was 52%, 13.3 %, 10%, 8%,44%, 0 % and 16% in market milk, ultra high temperature milk packs (UHT) , condensed milk , Milk powder, Damietta cheese, Kariesh cheese and Ras cheese, respectively, whereas its prevalence by indirect isolation was 64%, 20%, 20%, 48%, 52%, 40% and 36% in market milk, ultra high temperature milk packs (UHT) , condensed milk , Milk powder, Damietta cheese, Kariesh cheese and Ras cheese, respectively. B. cereus isolates were 100% resistant to colistin (CT), ampicillin (AM) and amoxicillin (AML). However, 83.01% were resistant to ampicillin-sulbactum (SAM), 67.9% resistant to streptomycin (S), 45.2% resistant to spiramycin (SP), 35.8% resistant to lincomysin (MY), 22.6% resistant to tetracyclin (TE), and 5.6% resistant to erythromycin (E). A prevalence of 58.6% for hblA, hblC and hblD was recorded, while a prevalence of 86.9%, 93.4% and 89.1% for nheA, nheB and nheC was recorded. Conclusion and clinical relevance: This study provides data on prevalence, contamination level and antibiotic sensitivity of B. cereus in milk and its products, suggesting a potential risk to health and the dairy industry.

Prevalence and Antimicrobial Resistance of Bacillus cereus in Milk and Dairy Products

ABSTRACT Objective: To investigate the prevalence of Bacillus cereus in milk and dairy products along with detection of its antibiotic sensitivity. Design: Descriptive study. Samples: One hundred and fifty samples of market milk, ultra high temperature milk packs (UHT), condensed milk, Milk powder, Damietta cheese, Kariesh cheese and Ras cheese. Procedures: Samples were examined for isolation and identification of Bacillus spp. via direct and indirect isolation, molecular examination and antimicrobial resistance. Further molecular examination was carried out in 46 isolates to detect hblA, hblC, hblD, nheA, nheB and nheC genes Results: The prevalence of B. cereus by direct isolation was 52%, 13.3 %, 10%, 8%,44%, 0 % and 16% in market milk, ultra high temperature milk packs (UHT) , condensed milk , Milk powder, Damietta cheese, Kariesh cheese and Ras cheese, respectively, whereas its prevalence by indirect isolation was 64%, 20%, 20%, 48%, 52%, 40% and 36% in market milk, ultra high temperature milk packs (UHT) , condensed milk , Milk powder, Damietta cheese, Kariesh cheese and Ras cheese, respectively. B. cereus isolates were 100% resistant to colistin (CT), ampicillin (AM) and amoxicillin (AML). However, 83.01% were resistant to ampicillin-sulbactum (SAM), 67.9% resistant to streptomycin (S), 45.2% resistant to spiramycin (SP), 35.8% resistant to lincomysin (MY), 22.6% resistant to tetracyclin (TE), and 5.6% resistant to erythromycin (E). A prevalence of 58.6% for hblA, hblC and hblD was recorded, while a prevalence of 86.9%, 93.4% and 89.1% for nheA, nheB and nheC was recorded. Conclusion and clinical relevance: This study provides data on prevalence, contamination level and antibiotic sensitivity of B. cereus in milk and its products, suggesting a potential risk to health and the dairy industry.

Prevalence of Human Brucellosis in a Suspected Population of District Swat

Background: Brucellosis is caused by a gram-negative, aerobic, non-spore forming, coccobacillus, transmitted by consumption ofcontaminated dairy products. Close contact with infected animals is also a risk factor. Diagnosis is difficult due to non-specificmanifestations like fever, back pain, arthralgia, muscle aches, and anemia, thereby diagnosis is based on laboratory tests.Although under rated, 50,000 new cases of human brucellosis worldwide are reported annually. In Pakistan, despite the diseasebeing endemic, data is limited. Moreover, the increased consumption of raw dairy products has posed an additional risk.Objective: To identify the prevalence of human brucellosis in the suspected population of District Swat.Material and Methods: This cross-sectional study was conducted at a tertiary-care hospital, of Swat from November 2017-October 2018. From the outpatient department, 150 participants were enrolled being suspected of having human brucellosis.Every participant was screened for Brucella antibodies by Serum Plate Agglutination Test (SPAT) and confirmed through Enzyme-Linked Immunosorbent Assay (ELISA) and Polymerase Chain Reaction (PCR).Results: The mean age of the participants was 29.65+11.27 years, 34% of which were 21-30 years of age. Most (62%, n=93) werefemales and a greater proportion of them consume fresh milk (45.3%), followed by fresh milk and milk pack both (30%). Around 119(79.3%) were positive on SPAT, 50.7% on ELISA, and 49.3% on PCR with a significantly higher proportion in females (p=0.001).Conclusion: Human brucellosis was found to be highly prevalent among suspected population exposed to raw dairy products witha definitive diagnosis found in almost half of the samples collected.

Quantitative Estimation of Casein in Different Milk Samples

Milk is an important part of human life and supposed to be a nutritious food which contain about 80% proteins. Milk proteins consist of 80% casein (soluble protein), 2-8% lactose (milk fat) and remaining is whey (byproduct of cheese and casein manufacture). Casein is more important and contain almost all essential amino acids. The purpose of the present work was to estimate the amount of casein in different milk samples including natural milk (cow, buffalo, sheep and goat) both in boiled and un-boiled form and ultra-high temperature processed (<i>Nestle Milk pack</i>, <i>Olper’s</i> and <i>Everyday</i> Liquid) milk. In all the milk samples <i>Nestle Milk pack</i> contains high casein (g/100mL) 7.39±0.021 while cow milk contains lowest casein (g/100mL) 4.91±0.036 in un-boiled form and 4.75±0.025 in boiled form. Milk is supposed to be more beneficial if quantity of casein increases. From this research it is concluded that sheep milk is more beneficial with casein percentage 5.64±0.01 in un-boiled milk and 5.52±0.021 in boiled milk sample in case of natural milk samples while in tetra-packs <i>Nestle Milk pack</i> is beneficial with casein percentage 7.18±0.021 and 7.39±0.021 casein (g/100mL).

Investigating Pre-service Teachers' Learning Transportation-Related Contents in the 2015 Revised Elementary Pratical Arts Curriculum

2015 개정 교육과정의 초등 실과에 새롭게 도입된 ‘수송’ 관련 내용 요소에 대하여 예비교사들이 수송 수단을 구상하고 제작하는 활동에서 이해하고 경험해야 할 내용에 대한 연구에서 다음과 같은 결과를 얻을 수 있었다. 첫째, 예비교사들이 수송 수단을 구상하고 제작하기 전에 쉽게 분해와 조립이 가능한 간단한 구조의 자전거 모형을 통하여 수송 수단의 기본 요소 장치의 작동에 대하여 학습하고, 벨트 풀리 전동과 기어 전동 등 기계요소 부품의 형상과 사용 특성에 관한 내용을 학습하는 과정이 있어야 한다고 판단되었다. 둘째, 예비교사들은 수송 수단의 구상과 제작에서 몸체, 바퀴 등의 재료, 수송 수단의 작동을 위한 동력원과 동력 전달 요소 및 구조에 대하여 의문을 나타내었다. 따라서 몸체 제작을 위한 재료는 사각 형상의 페트병이나 우유팩을 사용하는 것이 적절하며, 바퀴는 판매하고 있는것을 사용하는 것이 효율적이며, 동력원으로는 건전지를 이용하는 것이 적절하고, 동력 전달 요소는 벨트 풀리를 이용하는 것이 적절하다고 판단되었다. 셋째, 예비교사들의 대부분은 수송 수단의 종류로 자동차와 같은 육상 수송 수단을 주로 제작하였고, 기본 요소는 구동장치를 주로 적용하였으며, 동력 전달 요소는 벨트 풀리 전동을 적용하였다. 넷째, 수송 수단의 기본 요소 및 기계요소의 종류와 용도에 관한 내용의 학습, 수송 수단의 구상과 스케치, 수송 수단의 몸체 및 부품 재료의 특성에 대한 학습 등이 체계적인 과정으로 진행될 때, 예비교사들은 보다 더 창의적이고 바르게 작동하는 수송 수단을 제작할 수 있다고 판단되었다.This study aims to find out what pre-service teachers should understand and experience in the design and production of means of transportation which is indicated in the 2015 revised curriculum of Practical Arts for elementary schools. Research results are as follows. First, pre-service teachers should learn about the operation of the basic elements of means of transportation through simple structure models such as bicycle which can be easily disassembled and assembled. Mechanical component parts such as belt pulley and gear transmission should also be learned. Second, pre-service teachers questioned about the materials and wheels of means of transportation, about the power source for operating these means of transportation, and about the element, structure and method of power transmission. It is appropriate to use a rectangular PET bottle or a milk pack, and it was determined that it is efficient to use a wheel that is sold rather than manufactured directly. It is appropriate to use a battery as a power source to view the continuous operation mode of the transportation means and to use the belt pulley rather than the gear as a power transmission element for the convenience of production and efficiency of operation. Third, most of the pre-service teachers mainly made land transportation means such as automobiles, and the driving devices and belt pulley transmission were applied. Some teachers made maritime and aerospace transportation means and steering device was applied. Fourth, teachers could produce more creative and functional means of transportation if they learn about basic elements, the design and sketch of transportation means, about kinds and usage of mechanical elements, about the characteristics of body and parts materials of transportation means.

PENERAPAN HACCP DALAM PROSES PRODUKSI MENU DAGING RENDANG DI INFLIGHT CATERING

HACCP is one of the food safety systems which is done by analyzing materials, processes, and food products. HACCP analysis can be used as an effort to control the quality of the fi nal product in order to meet the requirements of healthy, safe and halal food products. PT X is a catering company for aircraft service users (infl ight catering). This company has implemented HACCP in every food production. This is a descriptive research by observing the process of rendang meat production. The application of HACCP in PT. X is done by controlling temperature and time during production process to prevent microbes growth. From ten application of HACCP according to SNI No. 01-4852-1998 about HACCP there is a point that has not been accordance with SNI monitoring. Monitoring activities are not routinely performed on blast chilling and dishing process. Pieces of coconut milk’s pack fall in to the pan when cooking process because the cutting of coconut milk pack is done on the cooking pan. Other HACCP principles like HACCP team determination, product description, fl ow chart reaction, hazard identifi cation, critical point determination, critical boundary determination of each CCP, corrective action, microbiological verifi cation, and documentation are well implemented.

A Semiotic Study: Cultural Misrepresentation in Pakistani Advertisements

This study analyzes the Pakistani culture’s misrepresentation in local brands’ advertisements. Three brands have been choose for this research: Lux (soap), Sunsilk (Shampoo) and Tarang (Milk pack). The research aims at the exploration of various signs, symbols and gestures that carry heavy connotative meaning and symbolic significance for the viewers; simultaneously highlighting the related issues. I will deploy a synthesis of semiotic analysis and critical theories for this analysis. Multiple images from advertisements have been captured for this study and Pierce’s model has been used for interpretation of all these signs. This is a multi and interdisciplinary study which is related to the different areas of culture, semiotics, and media. Keywords: Semiotics, misrepresentation, images, sign, culture, advertisements, symbols

Effects of low-fat milk consumption on metabolic and atherogenic biomarkers in Korean adults with the metabolic syndrome: a randomised controlled trial.

Previous studies of the health effects of low-fat milk or dairy consumption on the metabolic syndrome have yielded inconsistent results. The present study aimed to investigate the effects of low-fat milk consumption on traits associated with the metabolic syndrome, as well as inflammatory and atherogenic biomarkers, in Korean adults with the metabolic syndrome. Overweight Koreans with the metabolic syndrome (n = 58) were recruited and randomly assigned to either the low-fat milk or control group. The low-fat milk group was instructed to consume two packs of low-fat milk per day (200 mL twice daily) for 6 weeks, and the control group was instructed to maintain their habitual diet. Clinical investigations were conducted during the screening visit, on study day 0, and after 6 weeks. No significant differences in changes in body mass index, blood pressure, lipid profile and adiponectin levels, as well as levels of inflammatory markers, oxidative stress markers and atherogenic markers, were found between the low-fat milk and control groups. However, compared to the controls, significant favourable decreases in serum soluble vascular adhesion molecule-1 and endothelin-1 levels were found in the 12 subjects with high blood pressure and in the 18 subjects with hypertriglyceridaemia in the low-fat milk group. The present study did not demonstrate an overall beneficial effect of low-fat milk consumption in subjects with the metabolic syndrome. However, low-fat milk consumption may have a favourable effect on atherogenic markers in subjects with high blood pressure or hypertriglyceridaemia.

Outbreak of extended-spectrum β-lactamase-producing Escherichia coli transmitted through breast milk sharing in a neonatal intensive care unit

Routine surveillance in a neonatal intensive care unit (NICU) showed an increased detection of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-E. coli) in August 2012, following nearly a year without detection. To describe the investigation and interventions by a hospital infection control team of an outbreak of ESBL-E. coli in a NICU. Six neonates with positive cultures of ESBL-E. coli (five with respiratory colonization, one with a urinary tract infection), control infants who were negative for ESBL-E. coli during the study period, and mothers who donated their breast milk were included. A case-control study was performed to identify possible risk factors for positive ESBL-E. coli cultures and molecular typing of isolated strains by pulsed-field gel electrophoresis. The odds ratio for ESBL-E. coli infection after receiving shared unpasteurized breast milk during the study period was 49.17 (95% confidence interval: 6.02-354.68; P < 0.05). The pulsed-field gel electrophoresis pattern showed that all strains were identical, and the same pathogen was detected in freshly expressed milk of a particular donor. After ceasing the breast milk sharing, the outbreak was successfully terminated. This outbreak indicates that contamination of milk packs can result in transmission of a drug-resistant pathogen to newborn infants. Providers of human breast milk need to be aware of the necessity for low-temperature pasteurization and bacterial cultures, which should be conducted before and after freezing, before prescribing to infants.

Incidence and survival ofBacillus sporothermoduransduring processing of UHT milk

Purpose – The presence of Bacillus sporothermodurans in retail UHT milk along with milk from different points of a processing line was determined. This paper aims to investigate the effect of chilling, pre‐heating, UHT, reprocessing and H2O2 individually and in combination on the survival of B. sporothermodurans in broth.Design/methodology/approach – Standard plate counts were conducted for all milk samples and isolates from UHT milk were characterised using PCR. BS vegetative cells and spores in broth were subjected to various stresses encountered, during UHT processing of milk. Survival counts were conducted after all treatments.Findings – B. sporothermodurans was detected in retail UHT milk packs from only one processor. UHT treatment at 140°C for 4s eliminated B. sporothermodurans in broth. The combination of chilling and UHT was more effective in eliminating B. sporothermodurans spores than UHT treatment alone. H2O2 was also effective in eliminating B. sporothermodurans spores after 15 min of exposur...

Improvement of cellulase production in cultures of Acremonium cellulolyticus using pretreated waste milk pack with cellulase targeting for biorefinery

Cellulase production in cultures of Acremonium cellulolyticus was significantly improved by using waste milk pack (MP) that had been pretreated with cellulase. When MP cellulose pretreated with cellulase (3 FPU/g MP) for 12 h was used as the sole carbon source for A. cellulolyticus culture in a 3-L fermentor, the cellulase activity was 16 FPU/ml. This was 25-fold higher (0.67 FPU/ml) compared with untreated MP cellulose and was comparable to that achieved with pure cellulose (Solka Floc). As the pretreatment progressed, roughness on the surface of untreated MP cellulose became to be smooth, but development of fissures on the surface of pretreated MP cellulose was observed. Cellulase pretreatment of MP increased both the accessibility of A. cellulolyticus to the surface and number of adsorption sites of cellulase on the surface of MP cellulose, leading to improved cellulase production in the A. cellulolyticus.

Eight-channel ultrasonic device for non-invasive quality evaluation in packed milk

An eight-channel ultrasonic detecting device for microbiological quality evaluation of packed liquid foods is presented in this paper. This device makes possible a non-invasive detection of the microbial growth in liquid foods with no need to open the carton-based packages where they are contained. Thermal and humidity stabilization are required inside the measuring chamber. The changes in the liquid media produced by the microorganism growth induce variations in the ultrasonic propagation parameters giving a non-invasive evidence of the developing contamination. For that purpose, the amplitude and time of flight of an ultrasonic 800kHz tone burst travelling through an UHT milk pack are analysed. Inoculated and sterile packs were tested to evaluate the performance of this new non-invasive ultrasonic microbiological quality sensor.

Non-invasive and non-destructive ultrasonic technique for the detection of microbial contamination in packed UHT milk

An eight-channel ultrasonic device was developed to detect microorganism growth in UHT milk contained in carton-like packages without opening the packs. The system analyses automatically the amplitude and the delay of an ultrasonic pulse passing through packed UHT processed milk, being the coupling between the transducers and the packs accomplished in dry conditions. Changes in these parameters produced by different microbes are detected even when other physical–chemical parameters still remain within the sterility margins. Three different strains ( Bacillus cereus, Proteus vulgaris and Bacillus pumilus) were inoculated at different concentrations in UHT milk packs. Variations in the velocity and amplitude of the ultrasonic wave show the growth signature of these microorganisms. Growth detection was achieved between 7 and 48 h depending on the number and type of bacteria inoculated. The experiments show that conventional analysis like pH or acidity measurements could be substituted by this non-invasive technique.

An Explanation of Non-Sterile (Leaky) Milk Packs in Well-Operated UHT Plant

The commercial and widely used single value assessment (SVA) of the risk for the nonsterility of ultra-high temperature (UHT) processed milk is compared with the risk assessment obtained from a Monte Carlo assessment (MCA). The SVA of risk is shown to be of limited real value in accurately predicting the number of non-sterile milk packs. This is because there will not be one single and unique value for each of the UHT process parameters, but rather a distribution of values for each. The effect of distributions in each of the UHT process parameters on a more realistic risk factor P is highlighted through a Monte Carlo calculation with a distribution of practical values attributed to concentration of contaminant spores and thermal resistance, heating temperature, and residence time of the milk in holding section of the sterilizer. Importantly the MCA predictions show that a higher proportion of the number of milk packs will be non-sterile than is predicted by the SVA. This number of nonsterile packs is more or less the number that are anecdotally known to be found non-sterile in well-operated UHT plant, between 1 and 4 in 104. The cause of the non-sterility of these packs is traditionally attributed to leakage of pack material, or seal, and contamination either in processing, or storage and distribution. It is concluded that the occurrence of a fixed number of non-sterile milk operations associated worldwide with UHT plant, and greater than that predicted by the SVA, is the failure to take into account a distribution of values for each of the process parameters. The need for inclusion of a distribution of values for each process parameter is underscored through a comparison of the two methods of calculation of risk. In doing so, it is important to understand, that a risk factor much higher than the simple SVA prediction is highlighted with the MCA. A sensitivity analysis of the MCA prediction of risk could be undertaken to indicate optimum process parameter options for risk reduction in UHT plant. The usefulness of the MCA of risk to similar classes of food, fermentation and pharmaceutical processes should be borne in mind. The approach could be used with more sophisticated microbiological models of thermal inactivation, including non-linearity.

牛乳パックリサイクルの環境負荷評価

Environmental impact by recycling paper package for milk products (milk pack) was estimated using environmental I/O table in Japan. Present state of recycling technology and materials flow was also investigated. Production of 7.66×105ton toilette paper (1997 in Japan) was considered using recycled 2.001×105ton of milk pack (1997 in Japan) in function of recycle rate. In case of using PE coating film on milk packs for thermal energy in recycle process the impact becomes reduced with increasing recycle rate of milk packages.

Enterobacteriaceae found in high numbers in fish, minced meat and pasteurised milk or cream and the presence of toxin encoding genes

Enterobacteriaceae were found in high numbers after storage at 7°C in 6% of consumers packs of pasteurised milk or cream, in 31% of retailed fish and in 100% of retail packs of minced meat. Seventy two fresh-water fishes, 40 packs of minced meat and 430 milk packs were sampled. One hundred and eighty four isolates were randomly picked from Tryptone glucose extract (TGE) agar (30°C for 3d) or Violet red bile glucose (VRBG) agar (37°C for 1d). In minced meat, Serratia liquefaciens, Hafnia alvei, Rahnella aquatilis were frequently encountered. On fish, the most frequently found species were R. aquatilis, and in milk, the dominating species were S. liquefaciens, H. alvei and R. aquatilis. One to three isolates of Citrobacter freundii were found in all three food categories. Using a polymerase chain reaction (PCR) technique, the gene of Escherichia coli heat-labile toxin ( l t) was indicated in one fish isolate of R. aquatilis whereas heat-stable toxin genes ( s t) were indicated in four H. alvei isolates, two originating from fish and two from minced meat. Positive PCR-reaction for vero cytotoxin genes were found in one H. alvei strain originating from fish ( vt1), in two S. liquefaciens strains from minced meat ( vt2), and in a C. freundii reference strain. One of the st-positive H. alvei strains from meat harboured the eaeA gene involved in the attaching phenotype of enteropathogenic E. coli.

Amperometric monitoring of bacteria-induced milk acidity using a platinum disc microelectrode

The acidity induced by the action of bacteria in milk samples was monitored amperometrically by using a platinum microelectrode. The measurements were performed directly on commercial packs of milk, stored at 32 degrees C, and were continued for 9-10 d after inoculation. The data were compared with those obtained by measuring the pH of the samples and the results are discussed on the basis of the metabolism of each bacterial species. The effects of the following bacteria were examined: Staphylococcus aureus, Bacillus cereus, Streptococcus faecalis, Bacillus subtilis, Aeromonas, and Corynebacterium.

The Spoilage of UHT-Treated Chocolate Milk by Thermoduric Bacteria

The sporadic occurrence of swollen packs of chocolate milk at a local milk processing plant is the main reason for this investigation and to identify and characterize the spoilage agents. Of the 62 packs of chocolate milk collected, 15 became swollen within 24 h. All of these had high viable bacterial counts on plate count agar, whereas those that did not swell were free from bacterial contamination. There were two bacterial types found either individually or together in the swollen packs. Both isolates were confirmed as spoilers because when they were inoculated into intact packs, spoilage occurred within 48 h and the inoculant organisms were re-isolated from these packs. In addition, the onset of swelling was more rapid with increasing inoculum rate. Both isolates showed versatility in their ability to grow over fairly wide pH and temperature ranges both aerobically and anaerobically. Although they showed no evidence of sporulating, both isolates identified as Enterobacter sp. and Micrococcus sp. showed fairly high temperature tolerance but low H2O2 tolerance. The temperature-tolerant gram-negative rod which was identified as an Enterobacter sp. could have implications for the acceptable levels of heat treatment to be used in milk preservation in Trinidad.