Cheese Production Process Research Articles

A sequence dependent single machine scheduling problem with fuzzy axiomatic design for the penalty costs

In this paper, a scheduling problem on a single machine producing dairy products subject to variable due dates, earliness and tardiness penalty costs and sequence dependent setup times was studied. The main purpose was to meet demands of customers just in time whilst total penalty costs of earliness and tardiness were minimized. In addition, applicability of the schedules was appraised using Fuzzy Axiomatic Design (FAD) to determine earliness and tardiness penalty costs. A hierarchical approach consisting of meta-heuristic algorithms such as a tabu search and a genetic algorithm was proposed to generate proper schedules. In the first stage, an initial solution was found by the tabu search algorithm. The solution was improved using the genetic algorithm to find an optimum or a near optimum solution in the second stage. The proposed approach was employed on a cheese production process in the food industry. An instance of the algorithm was demonstrated to illustrate the applicability of the proposed approach and the results obtained were highly favourable.

Determination of Vitamin B12 in Dairy Products by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry.

Vitamin B12 is a water-soluble molecule composed of a tetrapyrrolic complex with a cobalt atom at its centre. It is an essential regulatory element, synthesized only by bacteria; for this reason it is present only in food of animal origin and the daily requirement for humans is about 1 to 2 mg. Since milk and dairy products provide a significant dietary cobalamin intake, an ultra performance liquid chromatographytandem mass spectrometry method was applied to samples collected at different stages along the process of cheese making in order to evaluate the distribution of this molecule. In particular, samples of milk, rennet, whey, ricotta cheese, curd, mozzarella cheese and caciotta cheese were analysed. Results showed a level of vitamin B12 about 10 times higher in whey and ricotta cheese with respect to the milk they are derived from. These data would confirm the tendency of cobalamine to concentrate in the proteic fractions along the cheese production process.

Genotypic and technological diversity of Brevibacterium linens strains for use as adjunct starter cultures in 'Pecorino di Filiano' cheese ripened in two different environments.

Twenty-two Brevibacterium linens strains isolated from 'Pecorino di Filiano' cheese ripened in two different environments (natural cave and storeroom) were characterized and differentiated for features of technological interest and by genotypic methods, in order to select strains with specific features to be used as surface starter cultures. Results showed significant differences among strains on the basis of physiological and technological features, indicating heterogeneity within the species. A middle-low level of proteolytic activity was observed in 27.3% of strains, while a small group (9.1%) showed a high ability. Lipolytic activity was observed at three different temperatures and the highest value was detected at 20°C with 13.6% of strains, while an increase in temperature produced a slightly lower lipolysis in all strains. The evaluation of diacetyl production revealed that only 22.8% of strains showed this ability, and most of them were isolated from product ripened in the natural cave. All strains exhibited only leu-aminopeptidase activity, with values more elevated in strains coming from the natural cave product. The combined analysis of genotypic results with the data obtained by the features of technological interest study established that the random amplified polymorphic DNA (RAPD) clusters obtained were composed not only of different genotypes but of different profiles based on technological properties too. This study demonstrated the importance of the ripening environment that affects the typical features of the artisanal product, leading to the selection of a specific surface microflora. Characterized strains could be associated within surface starters to standardize the production process of cheese, but preserving its typical organoleptic and sensory characteristics and improving the quality of the final product.

Microbiological Control of UHT Sterilized Milk and Milk Products and Effects on Consumers' Health in Western Algeria

The present study focused on the analysis of microbiological quality of various milk samples such as ultra-high temperature sterilized milk (UHT), melted cheese and yoghurt, obtained from dairy product factories in western Algeria. Hazards identification and development of a quality management standard for these subsidiaries evidenced that the sanitary quality was satisfactory. The result revealed detection of faecal origin contamination ‘total and fecal coliforms’ in both the yoghurt product and sample of melted cheese where the average content was(1.29±6.72-0.14±0.56 x 103cfu/g) and (0.14±0.6-0.022±0.275 x 103cfu/g) respectively. It is indicative that all samples were free from Staphylococcus aureus and Salmonella sp. The study demonstrated that prerequisite programs (PRP) will prevent the occurrence of microbiological hazards origin, which confirms the fact that hygiene measures are the best safety assurance. The hazard analysis of the production process of yoghurt and cheese allowed us to find out their causes, adoption of preventive measures for certain sensitive stages where hazards can be eliminated or reduced at acceptable levels, the determination of critical control points (CCP)and operational prerequisite programs ‘PRPo’, implementing critical limits, and monitoring plans. DOI: http://dx.doi.org/10.3329/mh.v3i1.19777 Microbes and Health, June 2014. 3(1): 21-24

Physico-chemical quality assessment of ultra high temperature sterilized milk and milk products in Western Algeria

The present study focused on the physico-chemical and bacteriological quality assessment of samples including ultra-high-temperature (UHT) sterilized milk, melted cheese and yoghurt, collected from dairy product factories in western Algeria. Hazards identification and development of a quality man-agement standard for these subsidiaries were established. The physico-chemical and bacteriological quality of products analyzed was satisfactory, with the exception of 20% of the samples of fruity yoghurts where the titrat-able acidity was relatively high 1.337 ± 0.143%. Prerequisite programs (PRP) established will prevent the occurrence of hazards microbiological origin, which confirms the fact that hygiene measures are the best safety assurance. The hazard analysis of the production process of yoghurt and cheese allowed us to determine their causes, preventive measures for certain sensitive stages where hazards can be eliminated or reduced to acceptable levels, the de-termination of critical points for mastery (CCP) and operational prerequisite programs (PRPo), establishing critical limits, and monitoring plans. Awareness actions and information on potential risks are essential for consumers.

Case of contamination by Listeria monocytogenes in mozzarella cheese

Following a Listeria monocytogenes detection in a mozzarella cheese sampled at a dairy plant in Lazio Region, further investigations have been conducted both by the competent Authority and the food business operatordairy factory (as a part of dairy factory HACCP control). In total, 90 dairy products, 7 brine and 64 environmental samples have been tested. The prevalence of Listeria monocytogenes was 24.4% in mozzarella cheese, and 9.4% in environmental samples, while brines were all negatives. Forty-seven strains of L. monocytogenes have been isolated, all belonging to 4b/4e serotype. In 12 of these, the macrorestriction profile has been determined by means of pulsed field gel electrophoresis. The profiles obtained with AscI enzyme showed a 100% similarity while those obtained with ApaI a 96.78% similarity. These characteristics of the isolated strains jointly with the production process of mozzarella cheese has allowed to hypothesise an environmental contamination.

EPIDEMIOLOGIA MOLECULAR APLICADA AO MONITORAMENTO DE ESTIRPES DE Staphylococcus aureus NA PRODUÇÃO DE QUEIJO MINAS FRESCAL

We studied the molecular epidemiology of Staphylococcus aureus strains potentially toxigenic, isolated from the production process of Minas frescal cheese in a small dairy plant in the state of Sao Paulo. For this, samples were taken during the period from June 2008 to July 2009. Samples were collected from the surface of the receiving and storage tanks of raw milk, the surface of the balance tank of pasteurized milk, the water supply system, the pipes and equipments, the hands of the handler and from the packaged cheese, totaling 140 samples. The colonies isolated on Baird-Parker Agar confirmed as Gram positive and positive for catalase, coagulase and acetoin production, were submitted to extraction of bacterial DNA using the Invitek - Uniscience® kit. Confirmation of the isolated species and enterotoxins SEA, SEB, SEC, SED and TSST-1 toxin was carried out through the amplification of specific fragments of chromosomal DNA. Among the 74 strains of isolated coagulase-positive staphylococci, only 41 (55.4%) strains were confirmed as Staphylococcus aureus , of which 25 (61.0%) were positive to the presence of staphylococcal toxins. The most frequently identified enterotoxin was SEA. The toxigenic strains of Staphylococcus aureus were more frequently isolated from hands of the handler (16.0%), raw milk receiving tank (12.0%), pasteurized milk for cheese making (12.0%) and fresh white cheese ready for consumption (12.0%). KEYWORDS: food safety; fresh white cheese; PCR; Staphylococcus aureus ; staphylococcal toxins.

Complete Genome Sequence of the 936-Type Lactococcal Bacteriophage Caseus JM1

The 936-type lytic bacteriophages are the most frequently encountered species infecting lactococcal dairy starters. Infection by members belonging to this species has a significant negative impact on the cheese production process. Here we report the complete genome sequence of the bacteriophage CaseusJM1, a 936-type phage isolated from an Irish dairy plant.

The effect of lactose, NaCl and an aero/anaerobic environment on the tyrosine decarboxylase activity of Lactococcus lactis subsp. cremoris and Lactococcus lactis subsp. lactis

The aim of this work was to study, under model conditions, combined effects of the concentration of lactose (0-1% w/v), NaCl (0-2% w/v) and aero/anaerobiosis on the growth and tyramine production in 3 strains of Lactococcus lactis subsp. lactis and 2 strains of L. lactis subsp. cremoris. The levels of the factors tested were chosen with respect to the conditions which can occur during the real process of natural cheese production, including the culture temperature (10 ± 1°C). In all strains tested, tyrosine decarboxylation was most influenced by NaCl concentration; the highest production of tyramine was obtained within the culture with the highest (2% w/v) salt concentration applied. Two of the strains L. lactis subsp. lactis produced tyramine only in broth with the highest NaCl concentration tested. In the remaining 3 strains of L. lactis, tyramine was detected under all conditions applied. The tested concentration of lactose and aero/anaerobiosis had a less significant effect on tyramine decarboxylation. However, it was also found that at the same concentrations of NaCl and lactose, a higher amount of tyramine was detected under anaerobic conditions. In all strains tested, tyramine decarboxylation started during the active growth phase of the cells.

<b>乳酸菌がチーズの製造と品質に及ぼす影響 </b>

ナチュラルチーズの種類は1000 以上とされるが、製造に必要な原材料は乳、凝乳剤、乳酸菌等の微生物および塩のみである。とくに乳酸菌はナチュラルチーズ製造時に重要な働きを示すだけでなく、製品の品質に及ぼす影響が大きい。Lactococcus 属、Leuconostoc 属を主体とした乳酸菌スターターは製造工程において原料乳のpH 低下および良好な凝乳反応を促し、乳酸菌由来のタンパク質分解酵素はチーズのテクスチャーや風味に多大な影響を示す。さらに乳タンパク質の分解産物であるアミノ酸はアミノ基転移酵素（AT 酵素）による異化作用を受け、セミハード・ハードタイプチーズの特徴的な芳香成分生成に関わる。Lactococcus 属のAT 酵素は良く研究されており、分子量38-43.5 kDa のサブユニットが2-4 量体を形成している。 またLactobacillus 属のLb. paracasei subsp. paracasei からもAT 酵素活性が示され、これらの酵素および菌株がチーズの品質に及ぼす影響について研究が進められている。

Staphylococcus aureus and Listeria monocytogenes in Norwegian raw milk cheese production

The aim of this study was to survey the presence of Staphylococcus aureus and Listeria monocytogenes during the cheese making process in small-scale raw milk cheese production in Norway. The prevalence of S. aureus in bovine and caprine raw milk samples was 47.3% and 98.8%, respectively. An increase in contamination during the first 2–3 h resulted in a 73.6% prevalence of contamination in the bovine curd, and 23 out of 38 S. aureus-negative bovine milk samples gave rise to S. aureus-positive curds. The highest contamination levels of S. aureus were reached in both caprine and bovine cheese after 5–6 h (after the first pressing). There was no contamination of L. monocytogenes in caprine cheeses and only one (1.4%) contaminated bovine cheese. This work has increased our knowledge about S. aureus and L. monocytogenes contamination during the process of raw milk cheese production and gives an account of the hygiene status during the manufacture of Norwegian raw milk cheeses.

VIABILIDADE DE Escherichia coli PRODUTORA DE TOXINA SHIGA (STEC) NÃO-O157 EM QUEIJO TIPO MINAS FRESCAL.

Shiga toxin-producing Escherichia coli (STEC) an emergent foodborne pathogen that cause diarrhea, hemorrhagic colitis and haemolytic uremic syndrome in humans, represents a public health problem all over the world. Cattle are the main source of STEC. STEC are transmitted to humans by contaminated food, mainly those of bovine origin as meat and dairy products. This study aimed evaluates the non-O157 STEC viability of artificially inoculated in the milk used for the Minas Frescal cheese’s production. The cheese was kept at 4°C and analyzed at 1st, 2nd, 4th, 6th and 10th days after its production. 100% (32/32) of the cheese storad under refrigeration during 10 days had been the STEC strains viable. These results show that minas frescal cheese can transmit STEC. The adoption of good manufacturing practices is important from milking to the cheese production process to reduce the contamination risks by non-O157 sorotypes. KEY WORDS: Food safety, Minas cheese, PCR, STEC.

Ectoine as a natural component of food: detection in red smear cheeses

Ectoine is a compatible solute accumulated in halophilic bacteria in response to high salt concentrations and offers protection from osmotic stress. The occurrence of compatible solutes is widespread among bacteria, yet ectoine has never been detected in foods. The use of an ectoine producing microorganism (Brevibacterium linens) in the surface ripening of red smear cheeses led to the question whether ectoine can be found in cheese. Therefore we examined samples from a variety of cheese manufacturers and different types of red smear cheeses for the presence of ectoine using HPLC and HPLC/MS analysis. Ectoine solely appears in the rind and was detected up to 178 mg/200 g red smear cheese, depending on several factors like ripening status and conditions throughout the cheese production process (e.g. salt concentrations of used brine baths).

Enteroxigenic Staphylococcus spp. and other microbial contaminants during production of Canastra cheese, Brazil

Canastra cheese is produced from raw cow's milk, and it is made at the farmhouse level using artisanal procedures and natural starters. The aim of this work was to determine the main hygienic-sanitary indicators and enterotoxigenic staphylococcal strains present during the manufacturing of traditional cheese of Serra da Canastra region, Minas Gerais state, Brazil. Samples from 10 farms were studied, and they included: water employed in the process, raw milk, natural starters, cheese curd before salting and cheese after five days of ripening. All water samples exhibited faecal coliform contamination above the maximum acceptable value recommended by Brazilian standards. Pseudomonas aeruginosa and sulfite-reducing clostridia were also isolated from the water samples. In five samples of raw milk faecal coliform were above the limits allowed by the Brazilian legislation. The counts of Staphylococcus spp. in milk were between <2.0 to 4.9 log.cfu.ml-1. The counts of microbiological indicators were higher in natural starters and curd. High levels of faecal and total coliform, as well as molds, were found in the cheese samples. In all cheeses analyzed Staphylococcus spp. were found in levels above 5.0 log.cfu.g-1. The enterotoxins (SE) most frequently produced by Staphylococcus spp. strains were SEB and SEC. A high number of coagulase negative Staphylococcus strains were also enterotoxin producers. None of the samples contained Salmonella spp. or Listeria spp. These results point out a need for improvements in the production process of the artisanal cheese produced at Serra da Canastra in Brazil.

Development and evaluation of antimicrobial natamycin‐incorporated film in gorgonzola cheese conservation

AbstractConservation of food products depends on product quality and packaging suitability. The objective of this work was to develop and evaluate the antimicrobial efficiency of natamycin‐incorporated film in the production process of Gorgonzola cheese. It aims to optimize the production process and increase shelf‐life and food safety for the consumer. Films with different concentrations of natamycin were produced and tested in Gorgonzola cheeses to evaluate its efficiency against Penicillium roqueforti on the cheese surface. Films with 2 and 4% natamycin presented satisfactory results for fungus inhibition and the amount of natamycin released to the cheese was below that allowed by the legislation. Copyright © 2006 John Wiley &amp; Sons, Ltd.

The influence of different kind of milk on quality of Sjenica cheese and Sjenica type cheeses made by autohthonous technology

In this paper, influence of the composition of autohtonous Sjenica cheese and composition of cheese made from cow milk in the type of Sjenica cheese were comparatively investigated. Autohtonous Sjenica cheese, made from ewe's milk and Sjenica type cheese made from cow's milk both had high content of moisture (53.46% and 59.56% respectively), which is the result of production process (coagulation time, curd processing, drying and salting). According to moisture content in fat free basis - MFFB (73.51% and 73.38% respectively) both cheeses belong to soft cheeses group, and according to fat in total solids - FTS (58.66% and 46.75% respectively) they belong to a group of whole milk cheeses. Ripening coefficient of Sjenica cheese made from ewe's milk (21.42%) was larger than ripening coefficient of Sjenica type cheese made from cow's milk (20.41%). Big differences in chemical composition of both cheeses are due to non-uniformly technology, which imposes need to assimilate technology process of Sjenica cheese production and fulfill geographic origin protection of Sjenica cheese as autohthonous cheese characteristic for wider area of Sjenicko-pesterska plateau.

Redesign of the Mozzarella cheese production process through development of a micro-forming and stretching extruder system

The aim of this paper is the analysis and examination of the industrial processes for Mozzarella pizza cheese (hereafter referred to as pizza cheese). Specific phases and mechanical devices are studied in order to optimise and rationalise the production cycle. This goal is reached by developing a new and innovative forming method. At present pizza cheese is produced in 1–5 kg pats whereas, as this paper intends to highlight, by forming the cheese in smaller-sized dimensions (5–10 g) the processes will benefit in terms of energy consumption and use of resources (equipment, water, time etc.). Another advantage would be that the customer would be provided with a ready-to-use product, without the need for additional cutting. The paper deals with an innovative process for pizza cheese production, by focusing mainly on the forming phase; a double-screw extruder with a productivity of 20 kg/h was designed and tested in order to evaluate its functionality and applicability. The most relevant spin-offs deriving from the new forming device are the elimination of the pre-hardening phase, the reduction of the chilling time of about 10-fold, the reduction of the total processing time of about 25% and the diminution of the refrigerant water consumption.

Laboratory-Scale Preparation of Soft Cheese Artificially Contaminated with Low Levels of Escherichia coli O157, Listeria monocytogenes, and Salmonella enterica Serovars Typhimurium, Enteritidis, and Dublin

The production of cheese with incurred low levels of pathogenic microorganisms stressed by the production process was the aim of the study. A standard protocol for the preparation of artificially contaminated soft cheese on a laboratory scale was developed. Milk for cheese preparation was artificially contaminated with pathogenic target microorganisms at low levels, between 1 and 10 CFU/ml. Two strains of Escherichia coli O157:H7, two strains of Listeria monocytogenes, and three Salmonella spp. (Salmonella enterica serovars Typhimurium, Enteritidis, and Dublin) were investigated. The food pathogens in the cheese were exposed to the entire production process. All three microorganism species survived the cheese production process and were detected in the final product at concentrations between 1 and 50 CFU/g. The cheese produced contains target microorganisms that have been exposed to curd formation, drainage, setting, and ripening. This cheese can be used to validate microbiological methods or to examine the target microorganisms in a natural food environment at low concentrations. It represents an alternative to artificial contamination of cheese by adding target microorganisms to a final cheese product.

Infectivity of cysts of the ME-49 Toxoplasma gondii strain in bovine milk and homemade cheese.

Analyze the infectivity and storage resistance of cysts of the ME-49 strain of Toxoplasma gondii in artificially infected bovine milk and homemade fresh cheese. Pasteurized bovine milk was infected with 10 cysts/ml of the ME-49 strain of T.gondii and inoculated in different groups of mice, immediately or after storage at 4 degrees C for 5, 10 and 20 days. Homemade fresh cheese was prepared with artificially infected milk, and also tested in groups of mice, using the same storage process. Infection was identified by the presence of cysts in the brain or serological testing in challenged mice after 5 weeks, confirmed by Western Blot and histology. The infectivity of cysts of the ME-49 strain of T.gondii was maintained in the milk even after storage for 20 days at refrigerator temperatures. Cysts were also able to survive the production process of homemade fresh cheese and storage for a period of 10 days in the same conditions. These data demonstrated that milk and dairy products could be an important source of T.gondii in human contamination, reinforcing the importance of milk pasteurization before any processing or ingestion.

An experimental analysis of membrane bioreactor performances with immobilized chymosin

Aim of the present work is the experimental analysis of a continuos flow membrane bioreactor with immobilized chymosin for the hydrolysis of milk k-casein, one of the steps in the cheese production process. Chymosin has been immobilized on the bioreactor membrane by ultrafiltering under pressure its solutions, continuously fed to the system in a total recycle configuration. Bioreactor performances are evaluated in terms of two different parameters: chymosin activity and its release. The former, indirectly, measures the amount of k-casein converted into reaction products ( para-k-casein and GlycoMacroPeptide, GMP); the latter quantifies the amount of biocatalyst that is removed from the membrane by the milk flowing stream. A theoretical approach, based on the boundary layer theory, has also been attempted to estimate the dependence of chymosin release upon the wall shear stress and on the back-diffusion phenomena towards the milk bulk. The experimental analysis of bioreactor behavior has been carried out, searching for the operating conditions and system configurations that maximized chymosin activity and minimized its release. Particular attention has been devoted to the selection of the membrane material: PolySulphone membranes offered the best performance during experiments, as compared to those of PolyPropilene and PolyVinilDeneFluoride. The system configuration that gave best results, both in terms of enzyme activity and of its release, was based on a continuous milk recycle to the bioreactor. Enzyme losses were confined to 5–10 mg/l range, whereas its activity always attained values high enough (>2 g/l) to promote the coagulation in the next heating step of destabilized milk. During the experiments, an optimal value of the recycle ratio, was also found.